K6JRF at the mic K6JRF's Page
formerly W6FZC

My Mercedes Benz
S500 Coupe

K6JRF's MB S500 Cpe
All pages on this site are best viewed with 1024 x 768 or greater resolution
(Updated: Jan 8, 2021)

What's New . . .
- Hydraulic Suspension System Leak and Repair . . . click here
- 2020 Smog Test Results for Merc and Honda . . . click here
- Parts for Hirschmann Auta Antennas . . . click here
- Battery Tester Ancel BA-101 Testing . . . click here
- Auxiliary Fans Cut-in Modification Update . . . click here
- HomeBrew DTC Tester updated . . . click here

Cool Harness Info . . . click here
[6/6/19] DTC#19 Eprom Info . . . click here
Performance Chip Info . . . click here
   W140 Electrical Troubleshooting Manual . . . click here  
Diagnostic Trouble Code Manual . . . click here

Exclusive Motors - San Diego, CA

I no longer recommend EM for your Mercedes repair. The management has broken confidence with me by their attitude and actions.

When the business first opened (20+ yrs ago), it was a excellent repair shop where its ONLY tech could repair ANY Mercedes no matter what! Other MB shops sent their "couldn't fix" cars to his shop. Sadly, he died in a tragic motorcycle accident and the shop went into turmoil. The silent-owner took over, hired MB techs and has enlarged their floor plan but I believe it was too much, too soon.

For 15+ yrs, I supported EM in every way I could . . bought a Mercedes from EM . . had service done there . . recommended EM for email I received . . sent people to EM and some bought cars based on my recommendation . . made many posts in Mercedes forums . . posted technical pages based on ideas learned from some EM techs . . absorbed all costs to keep an Internet presence for EM. Click here to see one of the pages posted in 2009.

In return, I could buy MB parts for my Cool Harness at cost + 10%. That's what it started out but as time went by, the EM profit margin rose to 25.5%. Not bad . . to make 25.5% profit from a few key strokes on a computer. Check out the actual LAST bill showing the "cost" and "my price" . . numbers don't lie!! Some data has been blacked out . .

Recently that support (as bad as it was!!) has abruptly ended. The agreements have been broken w/o giving me a valid explanation. Not a good way to treat a loyal friend and customer IMO. In addition, I was personally admonished for attempting buy some parts w/o prior approval from the owner. Of course, this was the way it was done previously. When asked why the change . . the owner said ". . I don't have time for this nonsense"!

The other day, I was there from morning to mid-day, the phone didn't ring for service appointments and there wasn't even one 'drive-in'! Maybe others have noticed their change in attitude??

So, sadly after 20+ years, I can't, in good conscience, recommend their services for your MB. It will take some time to find another shop(s) and when I do, it will be posted here.

Welcome to my Mercedes S500 Coupe auto page. The info here will assist you in troubleshooting the electrical systems.

The info here is organized into "menus" consisting of all of the main ECU (Electrical Control Units) for the W140. These ECUs all interact with each other via the CAN (Controller Area Network), so during an electrical problem it's difficult to conclude that just one ECU may be the cause because of the CAN interaction. It's best to read each menu item after studying MENU#1's Engine Management Schematic showing how the ECUs are interconnected. Menu#2 shows how to read DTC (Diagnostic Trouble Codes) from the car.

The page is updated regularly. If you have a specific request, please send Email Icon
Please do NOT ask questions re normal car maintenance items; consult your maintenance book for items that need to be serviced or replaced.

-Date- Engine Mngmnt Sys (EMS), Electronic Control Units (ECU), Diagnostic Trouble Codes [DTC] Menu
1/10/07 (1)Eng Mngmnt Sys, Maint and Diag Manuals Info, Elec Wiring Diagrams via Internet
1/13/19 (2) Diagnostic Connectors, CAN & Scan Tools
1/13/19 (3) Trisco 'PALM' Scanner: Updated
3/5/16 (4) On-Off Ratio (Lambda) Tests
7/23/12 (4a) MAF Contamination & Lambda
3/25/01 (5) Distributor Ignition Module [DI] DTCs
3/25/01 (6) Diagnostic Module [DM] DTCs
5/25/01 (7) Hot Wire, Sequential Fuel Injection Module [LH-SFI] DTCs
3/4/01 (8) Base Module [BM] DTCs
3/2/07 (9) Electronic Accelerator/Cruise Cntrl/Idle Speed Cntrl Module [EA/CC/ISC] DTCs
5/3/01 (10) Anti-lock Brake System w/ Acceleration Slip Regulation Control Module [ABS/ASR] DTCs
5/3/01 (11) Supplemental Restraint System [SRS] DTCs
5/3/01 (12) Anti-Theft Alarm System [ATA] DTCs
5/4/01 (13) Convenience Features [CF] DTCs
6/10/14 (14) Becker Replacements, DIN-ISO pin-out, Changing Euro/Amer formats and DTCs
6/5/07 (15) Automatic Air Conditioner [A/C] Operational Check and Diagnostics DTCs
8/13/07 (16) Fixing a leaking A/C Evaporator in a W140!
5/2/08 (17) Lower Engine Temperature w/ Coolant Additives
9/27/19 (18) Turn on the Auxiliary Fans at Lower Temperature
10/3/11 (19) 'Ticking' Noise from Hydraulic Lifters in a 119 Engine
6/22/09 (20) Modification of the Viscous Fan Clutch for M119 Engines
5/9/05 (21) Testing of Sachs Viscous Fan Clutch, 2100 013 032
3/30/07 (22) Engine Detailing: Novel Use of a Common Product
7/26/04 (23) Berg Werks: First Gear Switch Module and Security Switch
3/9/18 (24)ASR problem with my '94 S500 Cpe
8/18/05 (25) Fix your Seat Belt Extender easily
9/20/06 (26) SRS Light 'ON'; fix a faulty Seat Belt Switch
11/19/07 (27) Halogen Lamps and How to Aim S-Class Headlights & Fog Lights
10/24/18 (28) Troubleshoot & Fix a Door Closing Assist Problem
12/8/07 (29) Test your Instrument Cluster Easily
9/6/08 (30) Acetone Said to Increase Mileage
7/22/20 (31) Fix your Hirschmann Power Antenna
11/10/07 (32) Buying New Wheels and Tires for your W140
7/7/10 (33) Recondition your Mercedes Battery
7/7/15 (34) Maintain your Mercedes Battery
12/20/14 (35) Fix your "Clicking" Rear Headrest
4/3/17 (36) Broken Headrest Gear Repair
3/5/17 (37) Rear End Whine
8/6/14 (38) Fix Fuel Gauge Problems
7/8/15 (39) Repair Schumacher Charger
1/8/21 (40) Hydraulic Suspension System Repair
05/25/20 (41) Ancel BA-101 Battery Tester

- 20 Yrs of Smog Test Results: 2000 to 2020 -

The tables below summarize the results the 2000 to 2020 California smog tests for both cars: Mercedes S500 and Honda Accord LX. I decided to keep the test results and post them so as to serve as an easy way to instantly see trends. The table

Mercedes 1994 S500 Cpe
Test (rpm) CO2 (%) O2 (%) HC (ppm) - 100ppm CO (%) - 1% NOx (ppm) Result
645 13.1/14.5/13.0/14.9/14.5/14.9/14.8/14.7/15/15.2/14.8 2.4/2.9/0/0/0/0/0.2/0/0/0/0 4/5/3/4/0/1/1/3/10/7/11 0/0/0/0/0/.01/.01/0/.01/.01/.01 N/A Pass
2343 14.6/13.5/13.1/14.9/14.4/14.9/14.9/14.6/14.9/15.3/14.8 3.1/2.7/2.8/0/0/0/0.2/0/0/0/0 18/15/27/4/1/2/3/5/18/9/8 0/.01/.01/.01/.01/.01/.01/0/.01/.01/.01 N/A Pass

The car has consistently passed with flying colors and has done well over the years. The catalytic converter is original as is the "plumbing". Prior to the 2006 smog test, the O2 sensor, MAF sensor were replaced. And I decided that the use of K&N Air Filter was too much hassle, so I went to a standard paper filter. [Click here to see the contamination from K&N filter].

Mercedes Lambda Calculation
Mercedes The summary results of the CA Smog tests for my Mercedes were entered from the summary sheet into the program * to graphically show how the car's smog system is performing. After entering the numbers for "25MPH" from the 2020 smog results, you see that Lambda = 0.999 meaning that the Air/Fuel (A/F) ratio 14.69 making the fuel mixture RICH by 0.1%   Couldn't ask for better than that!

It's interesting to note that the readings have improved since then, especially the HC at highway speed. The pre 2004 results are much higher than the 2006 thru 2012 results although the 2020 test results are close to the 2000 results. I periodically clean the MAF sensor. As you see, the results have stabilized possibly due to the use of Seafoam . . which is ALWAYS added at fillup. Been doing this for 20 years!

Due to the full-time ASR, which is not defeatable, the NOX tests are not performed on the 'treadmill' b/c of the ASR control which causes the car to literally stop . . . Ask me how I know??

Similar to my Mercedes, I've kept the Smog Test results for my '90 Honda Accord LX. . . a car that is 30 years old! In 2012, many of the original smog accessories were replaced prior to the 2012 smog tests. As you can see, the 2010 results were very shaky. In 2012, a "pre-test" was done to see how bad it is and it was bad! Although it did pass, it was just under the NOx and HC limits.

Honda 1990 Accord LX
Test (mph) CO2 (%) O2 (%) HC (ppm) - 74ppm Max CO (%) - 0.69% Max NOx (ppm) - 530ppm Max Result
15 15/15.1/14.8/15.0/14/14.1/14.8/14.6/15/15.7/14.8 .1/.05/.1/.05/.1/.5/.2/.2/.2/.2/.2/0 21/24/15/24/31/72/13/5/12/18/8 .08/.09/.24/.09/.09/.68/0/0/.27/.14/.43 40/40/36/40/55/536/5/42/32/72/83 Pass
25 15/15.2/14.8/14.9/14.5/14.4/14.8/14.6/15/15.2/14.6 .05/.05/.0/.05/.1/.1/.2/.1/.1/.1/0 15/15/10/15/16/24/12/3/8/11/8 .06/.06/.18/.06/.09/.35/.02/.01/.23/.31/.61 25/26/24/26/31/129/2/9/15/10/186 Pass

In 2012, the Honda's smog components were in bad condition as most were original parts . . . with 148000 miles! The PCV long since ceased to perform and was now a "bilateral" valve. The air-filter was plugged solid and finally, the EGR valve was badly carboned. In addition, the O2 sensor was also original as was the catalytic converter. Note the readings were progressively getting worse with the years so in 2012, all major smog elements were replaced. After two (2) years, the results are still exceptional as shown in the chart. The Nox at 25MPH was only 10 ppm [limit = 530]!

So the $500 investment (including labor) to replace the 02 sensor, catalytic converter, PCV valve, air filter and spark plugs has shown to be a good investment. All in all, the CA smog Test results for 2018 show it to be quite good except that the CO is higher than previous years, so possibly the O2 sensor needs to be replaced before the next smog check in 2020.

Honda Lambda Calculation
Honda The results of the CA Smog tests for my Honda were entered from the CA Smog summary sheet into the program *. After entering the numbers for "25MPH" from the 2020 smog results, you see that Lambda = 0.983 meaning that the Air/Fuel (A/F) ratio 14.45 making the fuel mixture RICH by 1.7%!

The CO% and NOX readings have increased; the CO at 25mph = 0.61% which is JUST UNDER the limit of 0.69%!! The NOX reading has 'step-function' climbed from two-digits to three-digits. Although still below the limit (apx 530 ppm), it's an area of concern.

The higher CO (0.61%) reading indicates a rich mixture which points to incomplete combustion. Some causes are:
1) Air Filter - A dirty air filter will absolutely restrict air flow, thus disturbing the proper 14.7:1 air/fuel ratio required for optimum fuel combustion: Upon inspection, the 8 yrs old filter was very dirty so it was replaced.

2) Spark Plugs - Worn spark plugs have higher gaps that produce less 'spark' energy so they s/b replaced regularly: pulled all plugs:#2,#3,#4 plug gap in excess of 0.055"; #1 had a stalagmite growing on the ground electrode; all were 8 yrs old! Replaced all plugs w/ NGK (7098) ZFR5FGP spark plugs.

3) PCV Valve - A plugged or open PCV valve doesn't allow for gases to be mixed back into the throttle assembly. It was plugged with "gunk", so it was replaced with a new one: PCV1146DL.

4) EGR Valve - it recirculates metered quantities of exhaust gas into the engine intake system for increased engine efficiency, reduced fuel consumption and lower NOx emissions. It's easy for the EGR valve to become plugged or passage way reduced. Used some carbon solvent and let the valve sit in the solution for apx 3 hours. Some scraping and a little compressed air returned it to as good as new!

5) IAC Valve - this valve can cause surging at idle; the car's idle speed goes to apx 1800rpm then abruptly drops to 1100 rpms. This indicates that it is 'plugged'. Cleaning it usually fixes the problem . . . if not, it needs to be replaced. Inspection shows it was somewhat dirty but the gasket was crumbling due to age! Clean it, replaced the gasket and it seems to be working properly now. At KM A&H [858.268.3400] , the idle screw on the throttle body was adjusted to lower the idle to apx 800 rpm when car is fully warmed.

6) O2 Sensor - The O2 is responsible for delivering information to the Engine Control Unit) relating to the oxygen content in the exhaust stream after it has left the combustion chambers. The ECU will determine how much fuel to inject into the combustion chambers based on this data. The more oxygen in the stream, the more fuel the computer will deliver, and vice-versa. The CRACKED head that existed (2017 to 2020) probably contaminated the O2 sensor and a failing O2 sensor will cause increased carbon monoxide emissions. Also most manufacturers recommend replacement at 50 to 60K miles which was easily put on the car in 8+ yrs of driving! Replaced with a new NGK model.

7) Throttle Position Sensor (TPS) - The TPS relays information regarding the position of the air intake system's throttle plate. Most often a faulty TPS will cause high CO, as an engine's ECU always prefers to send more fuel rather then less, in an effort to avoid a lean fuel mixture and subsequently higher engine temperatures: After making all of the above described changed, the TPS was NOT checked b/c engine operated w/o any "TPS" induced problems. It may be checked in the future: and adjusted if need be. Grn=Neg; Yel=5V; Red=TPS voltage; reset=0.5V; full=4.5V

8) Engine Coolant Temperature Sensor (ECT)- Low engine temperature requires more fuel. When the ECU is unable to determine what the engine's accurate temperature is, it will not adjust fuel delivery properly; resulting in high CO. As you've read, the Engine Computer prefers to send more fuel rather then less to avoid a lean fuel mixture. Will replace it if the upcoming pre-smog test is not to my expectations.

The plan is to drive the car for at least two (2) months and then have a pre-SMOG TEST run. Will post the results here.

*  If you want to translate your smog parameters into Air-Fuel-Ratio (AFR), then download the Lambda Calculator Pro program to see how well your vehicle is "tuned". It's a very simple and straightforward program to install and use.
Air - Fuel Ratio Variations
Air-Fuel Ratio Variations One of the best 'visual' charts I've ever seen is the one shown here. It clearly shows the effects of air and fuel ratios on the amount of NOx, CO2, CO and HC generated.

It also shows how "good" your catalytic converter MUST be to remove and reduce the amounts of pollutants to acceptable levels that allow the car to pass California smog tests. The RED hash marks show the current CA Smog test limits.

Running the mixture with Lambda = 12.5 gives the best power and lower engine heat but raises the level of the main pollutants, HC and CO but lowered NOx levels. You can see that there isn't an "ideal" setting for Lambda to get the lowest value for ALL pollutants.

The best compromise is the Lambda setting at 14.7. The lowest amounts of HC, CO are produced but higher NOx levels. However, these limits MUST be reduced almost an order of magnitude to meet current CA smog test limits. A tough job for your catalytic converter.

A good discussion of the AIR FUEL RATIOS is here.
Test Only Smog Stations
As you may know, all older cars MUST be tested by a "STAR test-only" smog center. After searching and interviewing the owners, I chose to use  A&P Smog  located at 7835 Armour St, telephone 858-560-8874.

The YELP site shows some picture details of the site here. The owner, Chris was a Lexus/Toyota tech for 28 years and knows the emission systems for all cars. The A&P webpage is here. You can email them at Email Icon

The state of California wants to remove older cars, so the smog "checkover" is very detailed. They have forbid car warmup period. So now they want the tech to start the car, idle it for 2 minutes and go into the smog test. If the car was parked and shut off (as is the norm), the cat will be cold meaning that it could fail smog testing. Best to keep the car idling to ensure that the cat is hot.

It should be obvious that they want to remove the older cars from operation so you should make sure that the car is thoroughly warmed and has been taken on the freeway to fully heat the catalytic converter. A word to the wise!

Starting in Jan 2013, all 2000 or newer cars have be tested using their ON-BOARD systems; no interconnection to the smog stations equipment. Today (2014), I found out that the new-cars (2011 and later) test ok but that early cars have problems passing b/c of "glitches" in the test system and CA state software.

Auxiliary Fan Modification for All Mercedes

Cool Harness (c) K6JRF Get a cooler running Mercedes in 5 minutes! That's how easy it is to install either version of my Cool Harness(c) into your Mercedes Benz. Simply unplug the existing harness and install it into the CH(c) and your MB will reward you with a cooler operating engine.

Ever happen to you: While sitting in traffic after exiting the freeway, your TEMP gauge goes past 105C! So you shut off the A/C to cool the engine.

Well, you don't need to do that anymore!  My CH(c) tells the auxiliary fan(s) to turn on at a lower engine temperature so it will keep you engine around 8-10 deg C cooler than before. Either unit is foolproof, so you can't make a mistake and it only takes a short time to install. Simply unplug the car's harness and plug it into the Cool Harness and you're all done.

Since the engine runs cooler, you'll have more usable horsepower available, so it's a good investment for your MB.

Now there's two distinct models, so between them most all Mercedes models are covered. The original Cool Harness works for earlier Mercedes from 1987 to 1995. Typical models; 190E, 300CE, 300E, 400E, 500E, 500SL, 300SD, 320SEx, 420SEx, 500SEx, E320, E420, E500, S320, S420 and S500 cars.

Cool Harness V2 The Cool Harness-V2 model works with ALL Mercedes from 1995 through 1999 for all four (4) pin sensors as shown. Mercedes from 1995 thru 1999; C220, C230, C280, E320, E420, E430, S320, SL320, S500/600, SL500/600, CL500/600 and all others with the four pin sensor.

Both models of the Cool Harness(c) are constructed from the finest Mercedes - VDO - Xicon parts. The CH pins are all silver plated so they will not develop an intermittent connection. The CH-V2 employs a new Mercedes sensor along with precision value parts that guarantee a lifetime of service.

Over the past years, I received many requests for a Cool Harness that will work in '95 and on Mercedes but sadly there is no mating connector that will fit the new style four (4) pin sensor. So I've struggled with what could be done to accomplish this. But as many attempts where made to solve this problem, I couldn't come up with a clean packaged solution. One that an owner could 'drop-in' to their car and could be produced without excessive cost.

I considered such methods as having an injection molded assembly made that could fit inside the present sensor/connector combination but the expense was just too great. I finally got a 'workable' idea that I had originally considered some time ago but dismissed as being to difficult to construct. But after finding a source for sensors and needed parts, it appears this is a viable solution for the late model Mercedes owner. The Cool Harness-V2 operates under the principles as the older version so electrically, they are both the same in terms of 'how-it-operates'. The CH-V2 gives your car 'Cool Harness' action and, in addition, your car gets a factory spec sensor ensuring that its performance will be what it was at delivery time.

The Cool Harness-V2(c) fills the void for the late model Mercedes owner who wanted a Cool Harness. Now it's here after long last!

All of the comments for the original version Cool Harness apply to this version. The Cool Harness-V2 temperature cut-in point has been set to 94 deg C. So only ONE (1) version of the CH-V2 is needed.

The CH-V2 has two (2) separate sensors within the package. Mercedes changed to this combo sensor starting with '95 model year cars (and earlier for some other models). It combines the original CTS (B10/8) and ECT (B11/2) sensors into one housing. In the CH-V2, the ECT sensor is 'stock'. Also the modification to the CTS portion does NOT affect the ECT portion. Each sensor operates independently.

The CH-V2 is made using a Mercedes-Benz Original Part quaranteeing good-as-new performance along with the Cool Harness benefits. Unfortunately Mercedes parts cost have literally skyrocketed and that means a higher price for the V2 model.

Original Cool Harness: The price is $115 plus $8 s/h. S/H charges for USA orders only! Please contact for foreign order shipping.
Cool Harness-V2: The price is $115 plus $8 s/h. S/H charges for USA orders only! Please contact for foreign order shipping.

Both Cool Harness(c) models come with detailed installation instructions complete with detailed pictures of various MB engines showing the CTS location to assist you to complete the installation. If you can plug-in a toaster, you can install a Cool Harness(c) into your car.

For the original CH model, there are currently (2) models that you can select.
Personally, I use and recommend the CH-92 model.
Cool Harness Model Temp of Aux Fan(s) Cut-in Remarks*   [f/w = freeway]
CH-92 92C Aux Fan(s) may operate under f/w driving; will operate in stop/go traffic
CH-95 95C Aux Fan(s) may operate infrequently under f/w driving; will operate in stop/go traffic

* The remarks assume a hot day, 85F or above with 80% RH or higher with the A/C operating.
For a cool day, 70F and 60% RH, the remarks for CH-95 would apply for CH-92.

The higher the CH's cut-in temperature, the less the Aux fan(s) will operate. For example, with the CH-95, the fan(s) will only operate if the engine temperature attains approximately 95C which would most likely be during stop/go traffic. During freeway driving, the fan(s) may never operate. This assumes that your car operates between 82-92C normally, which most Mercedes do.

Unsolicited comments from enthusiastic Cool Harness users:

Comments from a New User
Today in the mail I received my Cool Harness [CH-92] and I want to thank you for such a cool (no pun intended) and clever device. The instructions provided with the harness could not have been any simpler or clearer to understand. Installation was straight forward and in literally 30sec installation was complete. I installed the harness the moment I got home from work, a 90min commute in 85 degree weather today so needless to say the engine was hot and the aux fans were running when I turned the car ['94 E420] off. After the installation I started the car up and the fans kicked in again and literally within 30sec the temp was down to about 85-90 degrees rather than the 110-115 it was while driving home. I will absolutely recommend your product to others. Thanks again.   = MN =

Cool Harness (c) K6JRF Cool Harness (c) K6JRF
Thanks, I am very satisfied and my SL500/94 too. The Cool Harness Model [CH-92] is working great and my car is cool. I want to will absolutely recommend your product to others.
Thanks again.

   = FMN =

Cool Harness (c) K6JRF Cool Harness (c) K6JRF
Received [Russia] and installed [CH-92] in my ['94 SL500].

You can check before and after in dead traffic.

Thanks a lot! Will recommend to my friends.    = RM =

Comments from a Customer in Jakarta
Hi - I know this is long overdue but I just wanted to let you know that I installed CH-V2 yesterday on my W124 '95 E320 and it works like magic. You should probably market this more actively in our part of the world [Jakata] where there's a big population of old Merc and the tropical weather is unforgiving. Thank you so much    = HL =

Then, to my surprise, he sent out this "testimonial" about the Cool Harness to the Jakata MB Group. Here's what he wrote.
ďI just wanted to share a solution to manage your engine temperature problem. Iíve tried various methods before: replace the radiator, viscous fan, Aux Fan, water pump, radiator coolant and thermostat but in the midst of Jakarta heavy traffic at noon, sometimes the temperature rises up to 105 degree. I ordered this Cool Harness from this site the other day and the outcome is unbelievable. The temp never exceeds 95 degree, even in a traffic standstill at mid-day. The mechanism is pretty simple, namely to trigger your high speed Aux Fan early at 92-94. Installation is also as easy as plug and play.Ē

He then added some 'instructions' to the MB group that they should fix fundamental problems first, such as radiator, viscous fan, etc (if any) and return the car to "stock" if the "85C" modification was employed.

Received the harness [CH-92]. Such a simple install ['95 S420] with great instructions. Thank you.   = SG =

hi-- i was wondering if the CH-95 adapter may still be available for my 1992 mercedes 300E? i would like to purchase one of these as well. The CH-92 works great, but just want to try a little variety.
I replied that he should take his family to dinner since the CH-92 will not materially change the engine cooling.
His reply:
I will hold off then on purchasing anything further for now. Thanks again for the honesty and for making this device. It certainly works well!    = JD =

I got [Croatia] the V2 and installed it ['95 S320] and it works perfect, I asked myself why the hell did I not buy it a few years ago! This is perfect Thank You!    = BB =
Wanted to send a quick thank you Ė ďCool HarnessĒ [CH-92] arrived today and was beyond easy to install ['94 E320]. I also checked the coolant mix, and as suspected, it was way rich! Between the coolant adjustment, additive (PI) and the Cool Harness, it feels like the car is running as the day I bought it with 77k original miles. The engine temperature never even approached the 100C line and I could verify the fans kicking in much earlier.     = CH =
Got the CH-92 in on Friday. I think it took me longer to find my keys than to hook it up. I ran the car ['95 S420] Saturday, what a difference!!! It got a bottle of purple ice last night too. Thank you for another great product!!!    = MK =
Received [Brunei] 2 pieces Cool Harness-V2. Just install one in ['94] C280. It works like magic. The temperature stays around 90 deg C. Thank you.     = PCF =
I'm impressed. Comes on at 92 [CH-92] and will keep it around 90 with AC in 90+ temps ['94 E500]. Without AC, it brings it down to below 82 where it runs in the winter. Kinda wish it turned off earlier. Am very pleased. Thanks.    = WW =
Thanks for promptly shipping your cool harness [V2] for my '95 S500 Sedan. I showed this to my master Mercedes tech and he was quite impressed. I installed it ['96 SL500] within 5 minutes over the noon hour and already I can see a dramatic change in the temperature gauge. Thanks again for all of your help.    = CG =
It works like a charm [CH-92]. In fact better than I thought. My next door neighbor stopped me as I was tooling down the street and I talked to her for 45 minutes while the car ['95 SL500] was running in 92 degree weather. Normally, it would have hit the top of the temp gauge, but this time it stayed at mid range.    = AC =
Finally, solved temperature problem, it was Temp gauge. Today I replace the sensor with new one (only 14$). Difference between real coolant temp. and temp. gauge is about 5'c. My car is '95 S320. After replace the new temp. gauge sensor with your CH_V2, coolant temp. never exceed 95'c even in hot weather with air conditioner on. Before installing CH_V2 and new temp. gauge sensor, my car's coolant temp. is 100~110C, sometimes over 115C in hot weather. Aux fan's kick in temp. is just bellow the 95'c!!! Thank you so much for your great job and advice. Now, I am so happy that I don't have to worry about engine temp.!!!!!!!  Best Regards    = HBY =
I recently ordered the CH-92 and I just wanted to get back to you on it, and tell you that this Cool Harness is an outstanding buy! I installed it in less than two minutes and from the very next day the car runs extremely cooler. I use to read the temp gauge before at 100 degrees and above, but now it reads just at or above 80 degrees constantly. I recently drove my S-class ['94 S500 coupe] on a road trip from Tampa Bay to Orlando Florida and it was about 98 degrees outside. Living in Florida the daily outdoor temperature is always steamy HOT, but that very day my benz ran a cool 85 degrees the entire trip. Overall, this device works and definitely recommended period. Hats off to you.    = PP =
I installed the Cool Harness [CH-92] right before I left for Vegas last Wednesday ['93 300TE], and it worked great! Went on to Parker Dam on Friday into 124 degree desert heat, uphill quite a lot, and the peace of mind I had in seeing my temp stay in the 100 degree range was priceless. I'm glad I found you.    = MH =
Got the Cool Harness [CH-92] a few days after you sent it [Austria!], but hadnít the chance of testing ['92 300D] it until the last few days, which were warm enough to use air condition. Well, what should I say? It works perfectly! Thanks for the easy transaction and the great product. I will talk to my father - I think he will need one for his S-Class too. ;-)   = CEL-H =
Got the Cool Harness [V2] today, it works great. I'm running at a cool 94 deg ['95 E320], and it was pretty hot today. Install took less than a minute!   = MP =
Real nice little product [CH-92], I figured it would help some but didnít know really how great it is. The other day Iím driving from San Diego to Temecula in 95+ heat, with the A/C going and I noticed when I hit the stop and go traffic the temp gauge stayed well below its normal spot (above the 80 line) and didnít think much of it, so when I got to Temecula I stopped by the ATM machine in 100+ heat and left the car idling in the parking lot. Well the carís ['95 E300D] temp gauge didnít move and when I got out I heard those fans just whirling away and thought yeah, thatís a good little product Ė thanks!   = TH =
I received the CH-92 a few weeks ago and installed same day and its working great. As you said, the temp does not go beyond 92C. I ran the car ['92 190E] on idle for over 5 mins and never went over 92C even with the A/C on. Great product and very well build. Thank you again and also you have a great web site on information.    = NM =
I just wanted to let you that I received my CH-92 last Friday and installed it ['91 300E] the following day and it works great! The temperature gauge stays below 100 degrees at all times......even with A/C on! Thank you for a quality product and outstanding service.    = AH =
I bought the cool harness CH-92 a few months ago and was discussing with you how it would work. It must have been related to outside ambient temperature (at the time it was 30). Ever since the warmer weather has arrived, It performs flawlessly, ['95 S600] just wanted to say thanks for a great product and a note on the temperature issue.   = NR =
Just wanted to drop you a not to let you know that I received the harness CH-92 and it is working beautifully in my car. My engine bay ['94 E420] and I would like to thank you for a cooler running car.    = AW =
I am one happy/cool Benz driver with your brilliant invention Ė I put it in [CH-92] and drove all day today with the coolest engine ever ['91 300TE]. Wish I knew about this several years ago as it is one of my pet peeves that MB makes the fan wait until the engine is toast before it kicks on Ė planned obsolescence? Thanks    = DF =
I received the Cool Harness, [CH-92]. The directions were great. It took all of one minute from the time the hood was up till the time I shut it to install ['93 300SE]. I immediately took it out for a full A/C on hiway drive. Yep, it works, stayed below 98 degrees centigrade the entire time. No more creeping up over 100 degrees C anymore. Thanks for a great product. You ARE the MBZ man!    = BS =
Just wanted to drop you an note to thank you for your device [CH-92]. It works great. Your installation instructions were accurate and it went right in. When sitting in traffic ['95 S500], the temp goes up to 90 and no higher. It used to make me nervous when the temp gauge would go up to the 100+ mark on the engine temp, now I don't have to worry about it.    = SL =
Thanks...installed the CH-92 and it works great! Both fans whirling a steady blow through the radiator at the 92 degree mark ['94 E420].    = FA =
CH-92 works well. I was afraid of it running the fan most of the time. At least in 70F weather, the thermostat keeps the engine just slightly below the CH-92 [cut-in]. When I slow or stop with the AC on I get the fan SOMETIMES. This keeps the engine temp in a very narrow band which is especially good for the '91 300SL as it has the infamous combination of iron block and aluminum head. I'll pass along the good news to my buddies.    = MK =
The "Cool Harness" [CH-92] is working GREAT, the car ['90 190E] never heats up beyond the set COOL HARNESS temperature, and I live in Las Vegas where the temperature is already hitting 100 degrees some days!    = BV =
Wow, what a difference it makes, I live in Los Angeles and its been hot, I just drove in la traffic with AC on, up and down hills, I got it [CH-95] installed in my '94 E420 at Mr MB Motors on Reseda he was awesome. wow! thanks for that!!!    = RU =
Just received my "Cool Harness", CH-92 in the mail. It is truly amazing. I installed in about 3 minutes with the engine ['92 400E] still hot. Instantly, my overall operating temperature is 20 degrees cooler. I tested it in the San Fernando Valley, where temperatures reach 105F and it worked perfectly. I even left the car idling, with my wife inside, AC on full for 10 minutes and the temperature did not come up. This product is truly incredible. Anyone with a MBZ should use one.    = BT =
Just got the CH-92, installed it and that thing works great! My '92 400E runs much cooler wish I had know about it sooner.    = GO =
Received the CH-95 today. Took 30 seconds to install ['92 300TE] and it works perfectly. The fans cut-in just shy of the 100C line on the temp gauge. That is exactly where I wanted it to cut in. Cooled the engine down to where it normally operates at (87C). This is a great idea. I think every one, especially in the South, should use one. It simply keeps the engine from fluctuating up into the high heat zone. Have a good day and I'm going to recommend this to my Mercedes mechanic.    = DW =
I received CH-92 on Friday, installed it per the very detailed and organized instructions included with package. I drove the vehicle ['94 E420] several times this weekend and the temp stays at worst between the 80-100 marks. You have kept my vehicle running in top condition, I can't thank you enough. Great products, great marketing, great service. . . thanks again.    = SS =
The cool harness, CH-92 is AWESOME! The temp ['94 S500] has not gone beyond 90C even once. Before this it used to linger between 100-110. THANKS SO MUCH!!! YOU ARE THE MAN!!!    = AM =
I received the Cool Harness yesterday and installed it immediately ['94 E420]. What a difference it makes. Heat index today in Georgia was between 105 and 110. Drove approx 35 miles this afternoon and temperature ran around 85 on the hwy. Sitting at lights it may have gotten to 100 but dropped down quickly. Thanks again!    = BT =
You can add me to your list of satisfied customers! I installed the CH-92 in my '92 500E in May and it has kept the car cooler, even in the summer heat of Dallas! If you even need a referral, let me know. I'll be glad to tell your prospective customers.    = DH =
This CH-92 is great. It fit my '92 600SEL V12 just fine. On the V12s, the 'blue based' temperature sending unit is in the very front of the car, next to the power steering reservoir, under a plastic cover with MB emblem. About 10 min job, and most of that was getting the original connector off. So far it seems to keep temp right at the low to mid 90's 'C on the dash temp gauge.    = BM =
I installed it right away and just came back from the test drive. Great product indeed, congratulations... It really took me only 3 minutes to install ['93 600SEL] it, including two to find out how to take off the plastic cover on the engine. It's the CH-98, and the fans cut in exactly at the 100C and shut off at 90C. That is exactly what I wanted!! Cheers from a satisfied customer.    = MM=
Got the cool harness today, its awesome. Works like a charm, engine stays cool. Had a little trouble at first finding the CTS on my '92 500E but after installing, it was awesome!    = PE =
The Cool Harness is absolutely awesome, it keeps the temp steady around 95 ['92 500E]. I always thought that the engine was like a CPU, keeping it cooler means it runs smoother. Very excited to see that it works as advertised.    = GN =
I received the CH-92 and installed it today. Works great! The fans kicked on immediately because the car ['95 S500] was hot.    = SF =
Super neat job on your design: the angled connector end and the shorter wire length is totally stealth. ['89 190E]    = FD =
Got the part, the direction are very clear and the fan works very well ['94 C280]. Here in South Texas is way to hot for not using this option. It is a quality product you have built it looks very professional and unless anyone knows what to look for I doubt even the MB technician would spot it! Thanks again.    = LH =
I installed the Cool Harness, CH-92 I got from you and my car ['89 190E] never saw 100C again! Very neat, looks like OEM and it works!    = MA =
I just wanted to say thank you. I received the part [CH-92] today and installed ['88 300SE] it in less than a minute. Now I can drive with piece of mind despite all the traffic and warm days here in Atlanta.    = RB =
I got a cool harness, CH-92 from you about a month ago and put it on my '94 C280 here in Tucson, AZ. I think it is a great part and I am sorry I didnít order it sooner.    = MK =
The CH-95s both work as advertised. Combined with the lower coolant ratios using WaterWetter in my '89 300TE, I definitely see cooler engine temps. My 420SEL was already running well within the 85-95 range. Whatever the reason, the M103 engine tends to run hotter than my 420SEL.    = EA =

To order one or more for your car, click here Email Icon to send an Email containing;
- your full name and address including city, state and zip,
- a phone number where I may contact you if needed,
- your Email address,
- Mercedes MODEL and YEAR info,
- CH Model number and quantity requested [quantity orders will receive a discount; will reply by Email]
- PayPal payment preferred. Will take cashiers checks, USPS Money Orders but no foreign MO!

PayPal is free to use as a buyer. There's no fees and it a very secure and instantaneous way of sending money with zero risk! Click on PAYPAL for complete information.

'Cool Harness' is copyright© 2000-2018 by K6JRF.
'Cool Harness-V2' is copyright© 2005-2018 by K6JRF.
All rights reserved.

Diagnostic Trouble Code #19 Repair Eprom for V8 Mercedes-Benz

This is one of the Diagnostic Trouble Codes (DTC) that is reported by the Diag Module (Menu#6) which states: Fuel injectors open/short or self-adaptation in LH-SFI control module (N3/1) at limit. This code lights the Check Engine Lamp (CEL) because it directly affects engine emissions. The "problem" lies in the Fuel Computer Module and it's not a 'nice' code as you will see!

Closeup of LH-SFI Fuel Computer The DTC_19 problem can happen in any fuel system. When it occurs, it means you have reached the limit of electronic adaptation correction. This problem originally started in hot humid climates and it caused the air/fuel mixture to get richer with great regularity. When the partial adaptation number reaches 0.85, the limit is reached and the CEL cames on!

So just erase and forget it. Sorry, this DTC is different from other codes. When you reset it, it will come back within a few miles of driving b/c the self-adaptation (S/A) is at the limit value. When you reset this code, you are just resetting the CEL light in the Diagnostic Module (Menu#6) but you can't change the S/A value itself. If you think you can get the car to pass a smog test, you are mistaken.

1990 thru 1994 W124s and W140s had only +/-15% correction built into the fuel computer's firmware. MBs solution is to sell you new firmware encased in new hardware at the cost of over $3000 (or more today-2018)! The firmware resides in an eprom that can be easily replaced. A number of companies have issued updated firmware by replacing the eproms. Some examples are BMW, Volvo and GM.

When dealing with this issue, the amount of correction is one consideration, but solving the deviation is another. If the mix has gone rich due to pressure changes or vacuum leaks, then fixing that is the correct solution. Many times it is due to a cracked/broken vacuum line including the "nipples", so that should be your first check point.

If nothing abnormal is found and if the car runs great, has no vacuum leaks, fuel pressure is within spec but still the CE lights showing DTC_19 meaning that the fuel computer is running "rich" and if it still has closed loop control of Lambda then the updated firmware (new eprom) will solve the problem. New firmware allows that old limit of 0.85 to be opened to 0.68. In other words, the limits have been changed from +/-15% to +/-32%. MB found that the system will still have closed loop control, thus the new limits.

The 119 LH cars seem to settle out with its long-term correction at or around 0.82. When this occurred in my '94 S500, it stayed at 0.82. It's now over 14+ years since the eprom was replaced, it's running fine and passing CA smog tests with no problem. After two years with the new eprom, the S/A was 0.85. I decided to replace the MAF and O2 sensor since those are the two main sensors that determine S/A. Today, the S/A is 0.93 with the new eprom, MAF and O2 sensor.

Detail of Replacement Eprom The upgraded eprom has fixed every instance of the DTC#19 problem, 114 MBs (as of 06/06/19)!

It's a very cost effective way to permanently solve this problem. It can't be ignored if you live in a SMOG state since even if the car's emissions are within limits (and many times they are!), it will not be allowed to pass since the fuel computer has an "emissions fault". Since their first sale in 2000, not one has failed. When my '94 S500 cpe developed the DTC#19 problem, I installed the upgraded Eprom and it been working since 2002.

The replacement eprom comes with a detailed installation instructions including the TSB info on the problem. You can replace the present eprom with a newly programmed unit with the new firmware as described above. The picture shows a closeup of the replacement eprom with the fuel computer open. It's a simple task to open the computer and replace the eprom. The instructions cover all details of this task.

Price is $115 plus $5 s/h. Please click on the icon to send me email.
Eprom Fitment Chart All MBs have LH-SFI w/ DI
Chassis Year Model Engine Remarks
124.034 94-95 E420 119.975 LH DI = Distributor Ignition
124.034 90-93 400E 119.975 LH  
124.036 90-93 E500 119.974 LH 500E 93
129.067 94-95 SL500 119.972 LH  
140.043 94-95 S420 119.971 LH  
140.042 7/91- 400SE 119.971 LH 420SEL, 400SEL 92-93
140.051 94-95 S500 119.970 LH 500SEL 92-93
140.070 94-95 S500 Cpe 119.970 LH 500SEC 92-93

Unsolicited Comments from DTC_#19 Eprom Users:

I did finally install the chip onto my '93 400e and the check engine is gone. I passed smog and I wanted to thank you. I can drive the car another 2 years. Thank you so much!!!    = CH =

Hello again. Just letting you know I have driven over a hundred and fifty miles ['95 S500 Cpe] and I have no CEL. Thank you very much,    = CT =
Got the chip . and got it installed . instructions made it easy . . slapped it back in the 1994 S420 . .ran scan. . jumped in . engine light is out . and didn't come back on . I turned the sucker on ran it and restarted her half dozen times to see if the light would come back on . . and . it may be my imagination but seems to be more powerful and run smoother ... very impressed . thanks a bunch ..    = RB =
I got the EPROM last week and installed it ['95 SL500]. So far I have had no problems. All codes are still clear and the car is running great.    = CV =
Thanks, went in [95 S500] without a hitch using your instructions. It's purring like 380 kittens now :-)    = JE =
Good evening I just wanted you to know I installed ['94 S420] the eprom and check engine has not come on 300 miles now    = MB =
Hi, chip is installed ['93 400E], cleared the codes. Car is running. Hoping for the best.    = MT =
Thanks! Quick and easy install ['92 400E], and its been several days with no CEL! And I'm pretty sure I'm getting 20%+ better gas mileage.    = CW =
Hi - installed the Eprom ['95 S420], reset the check engine light and everything seems to be working fine, no DTC#19. I spent over $1000.00 dollars with two different foreign repair shops to have that problem solved but code #19 always came back.    = RD =
I finally got some free time and good weather to install the EPROM ['95 S420]. 20 minutes and my S420 is alive again. The code is gone and so is a hesitation it had from a stop light.    = MK =
Chip arrived I think on Thursday, I installed today ['95 S420], only drove around the block but didn't miss a lick,. I am going to replace the EGR valve before anything else and then start driving it and see what happens.    = VO =
Received the new EPROM [94 E500] this evening and installed- cleared codes- runs like a new car. Thanks for providing such a valuable service/advice. Cheers,    = WC =
Hi, your chip seems to work great - just as you said. No more code 19 issues ['94 SL500].    = CS =
Hey thanks for the fast shipping, the chip ['92 400E] is on the car already. Looks like that was the problem but we will find out in a couple of day I will let you know what gos Thanks for everything and have a good night.    = JA =
Hi, Your chip seems to work great ['95 S500 cpe] - just as you said. No more code 19 issues.    = CS =
No problem, have installed your processor ['95 S420] prior, worked great Regards    = IJL =
Hi, just to let you know I received everything in a timely manner and all is well ['93 400E]. I no longer have the DTC code 19...and I did it myself with your help and thorough instructions. Thank you very much, you have helped make my car more enjoyable to drive.    = MC =
Hi FYI, installed the Eprom ['93 400E] a few days after I got it. Seems to run fine, no check engine light. Thanks,    = MW =

To order one or more for your car, click here Email Icon to send an Email containing;
- your full name and address including city, state and zip,
- a phone number where I may contact you if needed,
- your Email address,
- Mercedes MODEL and YEAR info,
- PayPal payment preferred. Will take cashiers checks and USPS Money Orders, no foreign MO!

DTC_19 Eprom is copyright© 2000-2018 by K6JRF.
All rights reserved.

Mercedes-Benz Diagnostic Trouble Code Manual

MB DTC Manual Bound w/ clear covers I've received many requests for a document that summarizes the Mercedes-Benz Diagnostic Trouble Codes (MB_DTC).  Well, it's here!  After collating a number of sources, the DTC document is ready to help you properly diagnose your car.

Got codes from the dealer but don't what they mean? A common complaint! Get a copy of the MB DTC Manual and you'll know what's wrong with your car's electrical, transmission, convenience and protection systems, all in one place! If you are a driveway DIYer or an independent MB shop, this Manual will help you diagnose and repair your car.

Is your '96 E320 giving you a P1581 code? You'll know what it means if you have the MB_DTC Manual!

Here's what is in the MB_DTC Manual:
. 160 pages complete showing 8, 16, 38 pin Diag Connector information
. Includes complete USA Model Identifier detailing Chassis, Engine, Transmission and Year
. Analog codes for 1988 - 1993
. Digital codes for 1993 - 1998
. All DTCs for systems such as DI, DM, BM, LH, CF, ATA, CT, AC, EA, ABS, ASR, ASD, SRS, etc.
. Diesel and Gas Systems: ELR, EDS, CFI, CIS, LH-SFI, HFM
. ETS, SPS, Digital Transmission Codes

MB DTC Manual on CD-ROM The product is available two ways:
Printed Manual:
Printed on quality white bond paper and bound with clear cover/dark back page ready for use in your shop or driveway! The Manual is printed double-sided, 160 pages total. The price is $49 + $6.50 s/h (USA orders). Shipped by USPS 'media' rate unless otherwise requested.
Please check for availability before ordering.

There are TWO (2) versions:
* For all Mercedes owners. This has all DTCs for all models and years. The complete manual or select sections may be printed for your use. The price for this CD version is $39 + $6 s/h.
This version is in the universal PDF (portable data format), so all you need Adobe's Acrobat Reader to read/print the DTCs! A current version is furnished on the CD if you don't not have it; simply install it and you're set to read the DTC Manual.

* Need to find out what those blinking codes mean now? And you have DSL or cable? Then get it via email. The email file is less than 1MB and can be downloaded in a few minutes with even slow speed DSL connection. The price is $29 complete. Can be printed whole or in part.

To build a compatible DTC reader, click here The schematic shows how it is constructed. You can build this inexpensive DTC reader from 'junk' box parts.

To order your DTC Manual, click here Email Icon to send an email containing;
- your full name and address including city, state and zip,
- a phone number where I may contact you if needed,
- your email address,
- CD-ROM, PRINTED Manual or E-MAIL. Quantity orders will receive a discount; will reply by Email]
- PayPal payment preferred. Will take checks (prefer cashiers), money orders, no credit cards!

PayPal is free to use as a buyer. There's no fees and it a very secure and instantaneous way of sending money with zero risk! Click on PAYPAL for complete information.

Diagnostic Trouble Code Manual is copyright© 2000-2018 by K6JRF.
All rights reserved.

   W140 ETM for Mercedes-Benz    

The W140 Electrical Troubleshooting Manual [ETM] on CD-ROM contains 1422 pages and is PDF format. It can be run from the CD or (preferably) copied to your computer. It runs from all versions of Adobe Acrobat or other compatible viewers.

MB W140 ETM on CD-ROM The detailed information is extensive and is organized as follows:

Volume 1 Model 140 - MY 1992 thru 1999
Volume 2 Model 140 - MY 1992 thru 1999
Volume 3 Model 140 - MY 1992 thru 1999

A - Table of contents, General Information (contains links to each of the group's index pages)
A3- Search aid for all groups (alphabetical listing)
A4- Abbreviations and Acronyms (an alphabetical listing with group application)
B1- Arrangement of wire and plugs (drawings showing the location of plugs and wires)
B2- Arrangement and location of relays and control modules (with drawings)
B3- Arrangement of grounding points (with drawings)
B4- Fuse boxes and their locations (with drawings)
B5- Arrangement of solder splices in wiring harnesses
B6- Arrangement and pin assignment of diagnostic connectors

All data is organized in "Groups" . . as shown below:

PG 444 in W140 ETM Group 00 - Overall vehicle
Group 07 - Fuel injection/fuel mixture control
Group 15 - Engine electrical (starting/charging)
Group 27 - Automatic transmission
Group 30 - Throttle actuation and speed control
Group 32 - Suspension (ADS)
Group 35 - Rear axle (ASD)
Group 42 - Brakes (ABS, BAS, ETS, ASR, ESP)
Group 46 - Steering (ESC, SPS)
Group 54 - Chassis electrical/instruments
Group 67 - Glass (rear window defroster)
Group 68 - Interior equipment (inside mirrors, sun shade)
Group 77 - Sunroof (tilting/sliding)
Group 80 - Central locking, convenience hydraulics (closing assist, ATA)
Group 82 - Body electrical (lamps, blinkers, headlamp cleaning, instruments, radio)
Group 83 - Climate control (automatic air conditioner)
Group 91 - Seats and restraints

Price is $95 plus $5 s/h.

To order a CD for your W140 car, click here Email Icon to send an Email containing;
- your full name and address including city, state and zip,
- a phone number where I may contact you if needed,
- your Email address,
- Mercedes MODEL must be W140/C140 between 1992 and 1999,
- PayPal payment preferred. Will take cashiers checks and USPS Money Orders, no foreign MO!

PayPal is free to use as a buyer. There's no fees and it a very secure and instantaneous way of sending money with zero risk! Click here for complete information.

W140ETM is copyright© 2000-2018 by K6JRF.
All rights reserved.

Performance Chip for '92-'95 V8 Mercedes-Benz
Typical Response for MB S500 Engine With and Without Chip Precision Auto Design's Performance Chip for V8s
PAD chip does not "fix" the DTC#19 code problem.

Get horsepower in 20 minutes! That's how easy it is to install PAD's POWER+CHIP in your 1992-1995 Mercedes Benz V8. Simply remove the Eprom chip using the step by step instruction sheet and install more hp and torque. To boost horsepower output, the chip has been re-designed to increase the fuel injection and timing parameters allowing for increased usable power through out the RPM range.

For a V8 5.0L engine, you can see from 10 to 15% horsepower increase and from 12 to 18% torque increase.

Checkout this video of a R129 SL500 [w/ PAD chip] vs Mercedes w210 E55 AMG at the drag-strip!

Use of high-test [premium grade] fuel and K&Nģ filters is recommended.

Normal price for all 8 cyl, 4.2L and 5.0L, 1992-1995 MB autos is $250.00.

Price: $145.00 + $5 s/h

PAD chip is warranted for 90 days for defects due to eprom failure.  No other warranty is expressed or implied.

Beside Ham Radio, I have another avocation, Mercedes Benz automobiles. Here's my story to date.

The 1994 through 1996 Mercedes Benz 'S' Series coupes were truly unique automobiles. From the front end styling, similar to the 'SL' but unique with its all anodized aluminum grill complete with MB star, made this car a "Teutonic" presentation that's not been equaled since.

I first bought a MB in 1995, a little 190E with a 4 cylinder 2.3L engine. It was nice but a little small and it lacked horsepower. It, surprisingly, did not get very good gas mileage, around 19 mpg. I next purchased a 1993 E300 4 door sedan. It was a rare "Sportline" model. The 3.2L, 6 cylinder engine was more responsive but lacked the ride quality. The Sportline chassis is tuned very tightly and rode a little too 'bumpy' for my taste.

Next I purchased a 1994 E320 Coupe. This was a unique auto, because 1995 was the last of that model forever! This is MB's mid size coupe. The color was midnight black with grey trim. The 3.2L, 6 cylinder engine was responsive and the ride was very nice. On the road, it got 24 mpg! An Alpine GPS system was installed and it made driving a pleasure, since one only needed to give me their address and it would take me there.

I have been looking for a clean S500 Coupe for about two years and it appeared a few months ago! Being a little fussy, there's some things that it had to have! First, the interior has to be 'black' with a dark color exterior. Of course, low mileage was desirable but what's more important is how was the car was cared for.

The service history was very good and it was garaged, another very important point. That's why the exterior looks so good. Of course, yours truly, did some refinishing to bring out that luster you see. Also had to do some minor engine work. Now you know what's been keeping me from the airwaves for the past two months! The only 'bad' feature is its 15.5 mpg city and 20mpg highway when you consider todays high gasoline prices.

The information on the following pages has been organized by major subsystems present in the car. After owning the car for about 4 months, the infamous 'Check Engine' light illuminated and that started me on a major task to find what caused it. Suffice to say that this was the impetus for the following diagnostic data pages. The good part was that I was able to fix the problem! The bad part was that it probably cost me about the same amount had the car been repaired by MB (because I had to get some test/diagnostic equipment) but, now, I can fix any problem that occurs!

I sincerely hope that the data supplied here will give the DIY mechanic the required information in order to properly troubleshoot and fix the complex engine management systems in the vehicle.

Technical Data for S-500
Model: S 500 (140.070 chassis)
Engine: 119.970
Mode of Operation: 4-stroke engine, gasoline injection
No of Cylinders: 8
Bore: 3.80 in (96.50 mm)dB
Stroke: 3.35 in (85.00 mm)Hz
Piston Displacement: 303.5 cu in (4937 cm^3)
Compression Ratio: 10:1
Output: 315 hp/5600 rpm (245 kw/5600 rpm)
Max Torque: 347 ft-lb/3900 rpm (470 Nm/3900 rpm)
Max Engine Speed: 6000 rpm
Firing Order: 1-5-4-8-6-3-7-2
Ploy-V-Belt: 2460 mm
Downshift points: D to 3: 124 mph (200 km/h)
3 to 2: 79 mph (127 km/h)
2 to B: 46 mph (74 km/h)
Rims - Tires
Rims: 7-1/2 J x 16 H 2
Tires: 235/60 R16 100H
Electrical System
Generator: 14V/140 A
Starter Motor: 12V/1.8KW
Battery: 12V/100 Ah
Spark Plugs: Bosch F8DC4 (org F9DC0)
Electrode Gap: 0.031 in (0.8 mm)
Tightening Torque: 15 - 22 ft lb (20 - 30 Nm)
Main Dimensions
Curb weight 4,785 lb; 1994, 4,695 lb
Trunk capacity 14.2 cu ft
Overall Length: 199.4 in (5065 mm)
Overall Width: 75.3 in (1912 mm)
Overall Height: 57.3 in (1455 mm)
Wheel Base: 115.9 in (2945 mm)
Track, Front: 63.1 in (1603 mm)
Track, Rear: 62.0 in (1576 mm)
Fuels, Coolants, Lubricants Capacities
Oil Filter: 8.5 US qt (9.0 l)
Automatic Transmission: 9.1 US qt (8.6 l)
Fluid change: 8.1 US qt (7.7 l)
Rear Axle: 1.5 US qt (1.4 l)
ADS: 2.1 US qt (2.0 l)
Power Steering: 1.4 US qt (1.3 l)
Front wheel hubs: 2.1 oz (60 g)
Windshield washer: 5.3 US qt (5.0 l)
Cooling System: 16.4 US qt (15.5 l)
Fuel Tank: 26.4 US gal (100 l)

Reminder: Don't Forget to Replace the Motor Mounts!

Motor Mount from my S500 at 98K miles We trend to forget about the car's motor support, the infamous motor mounts! Well, you shouldn't! When the MMs collapse, crack and split as shown, the engine effectively sits on the frame. All engine vibrations, and torque are transmitted into the frame.

This may not be disastrous but when you change them, you'll be pleasantly surprised. So do it if your car has 90K or better miles on it! Found a new pair for (you better sit down), $50 on Ebay. Sometimes you get lucky!

Enough words, where's the car . . . .
S500 Front View

The MB S-Class has consistently defined the capabilities that modern passenger cars should aspire to. From performance and comfort, to passive and active safety features, to reliability and durability, the S-Class has been an innovator and a leader. Powerful, agile and reassuringly secure, an S-Class automobile imparts sheer driving pleasure and enduring satisfaction like no other automobile in the world.

The S500 Coupe is the consummate V8 powered automobile and is the flagship of the Mercedes Benz line of autos.

S500 Rear Wiew

New Wheels and Tires . . .
Michelin Pilot Sport - Rear 255/45ZR - 18; Front 245/45ZR - 18; Wheels: Eurotech Model 530; 18" x 9.5 - rear. This wheel is extremely wide (1" greater than the 8.5) which makes it too big for the W140. Click here to see why.
S500 Rear Wheel + Tire
S500 Front Wheel + Tire
S500 Rear Wheel + Tire

Engine . . .
5.0L, 32V DOHC EFI Engine

The gasoline-powered 5 liter engine uses four valves per cylinder to increase the engine's capacity to 'breathe'. The faster and deeper the engine breathes, the more power it produces. To help improve torque at low and mid rpm, the intake-valve timing of the engine automatically adjusts. The result is vigorous off-the-line launch and reassuringly swift passing power.

Interior Views . . .
Passenger View

Much of what makes a Mercedes Benz a Mercedes Benz is the result of hand craftsmanship. The many Mercedes workers have learned the arts of upholstery and woodworking and these are passed down from skilled masters.

Look at the details of the interior: it consistently rewards your close scrutiny. The leather upholstery covers the entire seat, not just the seating surfaces. Inspect the wood trim: it's exquisite finish conceals a layer of aluminum that prevents splintering in a collision.

Back Seat View

The library quiet of the S500 is built to spirit the occupants over the road in security and elegance. Each is built to meet the highest expectations of its owner.

Navigon GPS System

The Navigon GPS Car Navigation, Model 7100 guides you turn by turn to your destination with high accuracy. It provides voice guidance prompts so you can keep your eyes on the road, while having the visual monitor for reference. It has been rated as very user friendly due to its ease of use and many options available for choosing your destination.
The Navigon uses colorful map displays as well as "3D" projection to show road geometries and upcoming intersections. Simple arrow guidance displays make navigation an effortless task. All information is thoughtfully laid out to minimize distraction and maximize safety.
The previous system employed a "commputer" that was housed in the trunk where the CD-ROM master 'map' were read and then displayed on the high-precision monitor. It was very "slow"!! The Navigon unit holds the complete US and Canada map system in 2GB of flash memory chip. The nice feature is its 'speed' at both calculating the route but also re-calculating a change in the route. The previous roof top GPS antenna is not needed since this unit has a built-in antenna. One great feature is the TMC mode where all local traffic conditions can be displayed and can form the basis of route modification.

Recent Interior Additions . . .

Thanks to various vendors, I've added a few extra enhancements to the interior. Also can't forget my wife's Christmas present that you see below; a instrument cluster overlay. Came direct from MB in Germany so it's probably from a newer S600 as a custom upgrade.

Here's the sum total of what's been added so far. I've found some sources for limited burlwood products from the following: URO Parts and Performance Products.

Burlwood Steering Wheel and Instrument Cluster

Burlwood Shift Plate

Burlwood Accent Buttons Burlwood Overhead Light Cover

Burlwood Mirror Plate

Burlwood Reading Light Plate

Burlwood Rear A/C Plate

Mercedes-Benz People

This section will highlight people that do unusual things to and about Mercedes-Benz cars.
Rudy contacted me regarding purchasing a Cool Harness and after one email lead to another, I found this talented man's 'real' talent, rebuilding junked Mercedes-Benz cars. Look at these photos and see if you don't agree! Here's what Rudy wrote to me.         JimF

I basically repaired this sad C280 into an AMG C36. Tried to come as close as possible to the specs of the C36. The project took me 4 months and I spent a lot of time on the web looking for junk yards to locate all the necessary hardware. The hardest part of the project was letting go of this beauty. The new owners reside in the Riverside, CA area. They previously lived in Connecticut.

I started about 4 years ago when a friend of mine in the insurance business told me about purchasing cars directly from him. At that time I didn't think much about it but now every 3 months I purchase a Benz, rebuild and sell it. Funny cause it's not for the money but rather a hobby. Besides nothing like seeing the end results of these beautiful cars!

I don't do this full time. I'm a Systems Administrator (MCSE) during the day and rebuilding cars is my hobby. The only thing I don't do on these cars is the welding, painting and well, now I will be able to reset codes thanks to your scanner. All else is done by me and sometimes with my wife's help! I don't have a web site but you are welcome to show off these pictures on your site. I'll send you pictures of the '89 190E 2.6 that I restored for my wife in the near future.

Rudy Pullano
Click here to send email to Rudy:  Email Icon

"My Mercedes-Benz S500 Coupe"

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All other brands, trademark's and names are property of their respective owners, are solely used to identify their respective products, and not to indicate any affiliation or relationship between "My Mercedes-Benz S500 Coupe" and those owners.

This information contained on "My Mercedes-Benz S500 Coupe" page is subject to change without notice and is provided "as is" with no warranty and shall not be liable for any direct, indirect, special, incidental or consequential damages in connection with the use of this material or any of its references. Use them entirely at your own risk. The author cannot be held responsible for any damage, direct nor consequential, caused by the use of, or inability to use the techniques or information presented here. Use of any of the techniques, or information presented here implies agreement with these terms.

Copyright © 2000-2018 by K6JRF.

Mercedes Links

Looking for quality parts for your S-class car? Checkout Eddie Alberini for great prices. He has consistantly supplied me with 1st class parts and supplied a used differential that solved my clunking rear end problem.

He has moved to Oppenheim, NY. Call him at 508-244-0593 anytime and tell him that I sent you! He is setting up an new bldg for used Mercedes parts. His email address is Email Icon. Besure to include your PHONE NUMBER so he can contact you. Signal coverage is spotty at the present.

. . . Victor's excellent site for MB repairs of Wiring Harness and Throttle Actuator called RestoreYourMercedes.

. . . Diag Trouble Codes for 'E' class (190s, 300s, 320s) DTCs by Bat Automotive

. . . Pictorial DIY articles for Mercedes repairs at Peach Parts Wiki

. . . Find MB replacement parts at the Peach Parts Shop

. . . More places for MB replacement parts at the R&R Import Auto Parts

. . . Mercedes scanners, tools, test and diagnostic equipment at Technic Tool Supply

. . . Unique all-natural engine cleaner that works at Auto-RX.

. . . Repair/rebuild of Mercedes Climate Control Systems and
Electronic Throttle Actuator by Beckmann Technologies

Miscellaneous Links

. . . In San Diego, for computer/laptop repairs or Windows problems, call Ed Koperda.   His 27 years of experience guarantees that your computer or laptop will be repaired quickly and at a reasonable price. You won't be sorry. Tell Ed that I sent you.
Call 619 584-9279 for an appointment.

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Visitors since July 3, 2000