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: Jun 25, 2014)

What's New . . .
- Updated Hirschmann Antenna Repair Info . . . click here
- Updated Becker Radio Repair Info . . . click here
- Updated ETA repair information and sources . . . click here
- California Smog Test Results w/ Lambda including "Honda" Accord . . . click here
Cool Harness Info . . . click here
DTC#19 Eprom Info . . . click here
Diagnostic Trouble Code Manual . . . click here
PAD Performance Chip . . . click here
Exclusive Motors . . . click 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
8/25/10 (2) Diagnostic Connectors, CAN & Scan Tools
1/22/08 (3) Trisco 'PALM' Scanner: Updated
10/19/07 (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
4/2/13 (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
2/6/14 (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
3/1/13 (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
6/25/14 (31) Fix your Hirschmann Power Antenna
11/10/07 (32) Buying New Wheels and Tires for your W140
7/7/10 (33) Recondtion your Mercedes Battery
7/7/10 (34) Maintain your Mercedes Battery
6/27/09 (35) Fix your "Clicking" Rear Headrest
7/12/10 (36) Rear End Whine

- 12 Yrs of Smog Test Results: 2000 to 2012 -

The 2012 California smog test for my Mercedes S500 was completed recently. I've kept the previous test results so I decided to see what, if any, the results might show. The table below summarizes the 2000 to 2012 smog tests run every two (2) years.

The car passed with flying colors and looking back, has done well over the years. The catalytic convertor is orginal as is the "plumbing". Prior to the 2006 smog test, the O2 sensor, MAF sensor and K&N Air Filter were all replaced! [Click here to see the contamination from K&N filter].

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. Significant change!

Mercedes 1994 S500 Cpe
Test (MPH) CO2 (%) O2 (%) HC (PPM) CO (%) NOx (PPM) Result
15MPH 13.1/14.5/13.0/14.9/14.5/14.9/14.8 2.4/2.9/0.0/0.0/0.0/0.0/0.2 4/5/3/4/0/1/1 0.0/0.0/0.0/0.0/0.0/0.01/0.01 N/A Pass
25MPH 14.6/13.5/13.1/14.9/14.4/14.9/14.9 3.1/2.7/2.8/0.0/0.0/0.0/0.2 18/15/27/4/1/3 0.0/0.0/0.01/0.01/0.01/0.01/0.01 N/A Pass


Similar to my Mercedes, I've kept the Smog Test results for my '90 Honda Accord LX. Since the car is 22 years old and has original smog accessories, it is time to replace/clean so that it will pass the 2012 smog tests. As you can see, the 2010 results were very shakey. I had a 2012 "pre-test" 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
The smog data for 2000 and 2008 is missing denotd by the "/-/" sign.
Test (RPM) CO2 (%) O2 (%) HC (PPM) CO (%) NOx (PPM) Result
15MPH -/15.1/14.8/15.0/-/14.1/14.8 -/0.05/0.1/0.05/-/0.5/0.20 -/24/15/24/-/72/13 -/0.09/0.24/0.09/-/0.68/0.0 -/40/36/40/-/536/5 Pass
25MPH -/15.2/14.8/14.9/-/14.4/14.8 -/0.05/0.0/0.05/-/0.1/0.2 -/15/10/15/-/24/12 -/0.06/0.18/0.06/-/0.35/0.02 -/26/24/26/-/129/2 Pass

The Honda's smog accessories were in bad condition; they were ALL original parts . . . with 148,000 miles! The PCV long since ceased to perform and was now a "bi-lateral" 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 and the "red" values show the 2012 PRE_SMOG TEST to see how bad it is. The results of the 2012 with the replaced smog elements are shown in "blue". Look at the change in the HC, CO and Nox results . . ie, Nox from 536 to 5 . . big difference!

So for about $500 total (including labor), 02 sensor, catalytic converter, PCV valve, air filter and spark plugs were replaced. The EGR valve was cleaned and is as good as new. All in all, the CA smog Test results show it to be as good as a new Honda!

Test Only Smog Stations
As you with older cars know, you MUST take it to a "test-only" smog center. I use and recommend Gary's test center. He's the owner/tech of 15 Minute Smog. He stated that the "state" has forbid car warmup period. He used to rev the engine and hold it at 2000+ rpm to ensure that it would have a "chance" to pass smog. Now they want to start the car, idle it for 2 minutes and go into the 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.

He said that the smog test software can't be re-run as could the older versions. If there was an "error" the test director could abort and restart the test. Not so today, so there's no room for an "oops"!

It should be obvious that they want to remove the older cars from operation so you 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 will be tested using their ON-BOARD systems; no interconnection to the smog stations equipment. I anxious to see how that is going to work out?? Older cars will still be tested as they are now.

If you want to translate your smog parameters into Air-Fuel-Ratio (AFR), then download the Lambda Calculator Pro program and see how well your vehicle is "tuned". Very simple and straightforward program to install and use. My S500 cpe's AFR is "1"; ie Lambda = 1 at both 15 and 25MPH. Can't be better than that!

Honda Lambda Calculation
To plot the results of the CA Smog tests for my Honda, simply enter the numbers from the summary sheet into the program and it will show how it's performing. After entering the numbers for "25MPH", you see that Lambda = 1.008 meaning that the Air/Fuel (A/F) ratio is 14.82 yielding fuel mixture at 0.8% Lean.

Honda


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 five 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, it 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. 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.

Original Cool Harness: The price is $90 plus $5 s/h. S/H charges for USA orders only! Please contact for foreign order shipping.
Cool Harness-V2: The price is $90 plus $5 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:

Special 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 =

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© 2000-2012 by K6JRF.
'Cool Harness-V2' is copyright© 2005-2012 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.

CD-ROM: There are TWO (2) versions:
1) 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.

E-mail: 2) Need to find out what those blinking codes mean now? And you have high-speed DSL or cable? Then get it via email. The Manual is 5MB and can be downloaded in a few minutes w/ a high speed DSL connection. The price is $29 complete. Note that this version cannot be printed. If you require a hard copy, then purchase the CD-ROM version above.

To build a compatible DTC reader, click here [schematic is at the bottom of the page] and build an 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© 2000-2010 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 occurs in 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. 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! 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, 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 updated firmware (new eprom) will solve the problem. New firmware allows that old limit of 0.85 to be increased to 0.68. In oher words, the limits have been increased 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 5+ 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 new eprom has fixed every instance of the problem, 90 MBs (as of 7/19/14)! 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".

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 $99 plus $6 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

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© 2000-2010 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 is warranted for 90 days for defects due to eprom failure.
No other warranty is expressed or implied.

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: $125.00 + $6 s/h


Exclusive Motors
Exclusive Motors Front Marquee

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In San Diego, you would be hard pressed to find a better repair shop for early or late model Merecedes-Benz, diesel or gas.

Click here to browse their remodeled facilities that features expert service and fair prices.


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 road 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
Transmission
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.

Most of the burlwood products shown here can be purchased from Performance Products. You need to get their catalog since all of the burlwood parts are not shown on their website. Call their toll free number to request the catalog.

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.
The BEFORE Pic The AFTER Pic
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

DISCLAIMER - K6JRF Page
"My Mercedes-Benz S500 Coupe"

Mercedes-Benz is a trademark of Mercedes-Benz of North America, Mercedes-Benz USA LLC and other Mercedes-Benz corporations. The words Mercedes-Benz is solely used to identify a make of automobile and do not imply or indicate any affiliation or relation of the "My Mercedes-Benz S500 Coupe" with the manufacturer or their distributors.

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 © 2000-2010 by K6JRF.

Mercedes Links

Looking for quality parts for your S-class car? Checkout S Class Eddies for great prices. He has consistantly supplied me with 1st class parts and recently supplied a differential that solved a problem with a potentially large $$$ drain. Please tell him that I sent you!

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

. . . A DIYer?? Find the needed repair info from AUDIO to WHEELs from MBZ.ORG.

. . . 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.   Not convinced yet?
Check out a well documented test on a high mileage '93 Nissan 240SX


. . . 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 17 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.

. . . Repair/rebuild of Mercedes A/C Systems and general automotive repairs including smog testing at Denny's Automotive on Santa Fe St in San Diego. Telephone Denny at 858 274-4961 for prompt service and excellent repairs.
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