1992 500E "ASR/limp home mode" problem continued
 

This thread is a continuation of a discussion in the thread titled "1994 E500 ASR problem" Since my car is a '92 500E, and the thread diverged from the original problem symptoms, I thought I'd start a new one, relevant to my specific symptoms, which are:

Intermittently, and with increasing frequency, the ASR light goes on during moderate accelleration or while cruising. Simultaneously, the car goes into "limp home" mode (reduced throttle response and performance, delayed shifts, no cruise control). On two occasions, the Check Engine light has come on as well as the ASR light. The symptoms are cleared when the car is shut off and restarted. Diagnostic Fault Codes are numerous: 17, 6, 2, 7, 96, 224.

The car has 109K miles.

Well, my "ASR/limp home mode" problems still persist. I've now had the upper wiring harness replaced, the idle speed switch replaced, and finally the throttle actuator replaced. Those are all the items that were covered in the prior thread, and I expected that the problem would be solved. Driving home from the shop with the new throttle actuator, however, the car's symptoms returned.

The technician that installed the new throttle actuator noted another possible step in the puzzle. There was a recall (MBNA 30/4) on the Electronic Accelerator Control Module. On a 500E, the version number of the EACM should be K10 or greater. Mine is K9. So, back to the dealer this morning. I'm looking forward to confidently mashing the fast pedal again!

Greetings Mark- and thanks for sharing the updates- unfortunately can't help with info on this, but am hoping you get your pristine '92 back fixed soon!


-fad

ASR light
 

I have a 96 S500 so I don't know if it helps but here goes.
If my car sat overnight, when I started it both the EPC and ASR lights came on on the dashboard and the car was in limp home mode. If I restarted it again and again(up to 30 times) eventually, the light went out and I was off and running.

Diagnostic showed code 1580 EA/CC/ISC actuator.

They replaced the "slide actuator" and I've since been trouble free.

It sounds like you may have been down this path already, but I hope this might be someplace else to look if you don't get better advice somewhere else.

KG
96 S500

Hi Mark,

Is the EACM the black box located by the accelerator pedal?

Hope your car is fixed soon.

roas, on the 500E, the EACM is one of the electronics modules that are in the weather-tight box that is located where the battery is on a "normal" W124 chassis - in the corner near the firewall on the passenger side of the engine compartment. It is something like a $2,200 part, from what I've read so far. I'll return to my dealer on Monday with supporting material to determine if there was in fact a recall on that part. So far, they say "no."

Mark,

I'm not sure what you mean by upper engine harness but I had my harness replaced (the one that connects to the blue and black temp sensors) and my car's (93 500E, 40K mi) been trouble free since. It was exhibiting the same symptoms as yours and was even sputtering in some cases, exhibiting a sort of overheat situation which was always fixed by unplugging the wire to the blue temp sensor (which then left the aux fax working always).

Sure hope your car's starmarked!

Cheers!

Oach, lets hope it's not the EACM! My "indy"(independant) tech in his quest to sort out my ASR Light on determined that a black box under the Drivers carpet was the culpret, it wasn't. I'm not sure how he came up with this conclusion as I was not present at the time, I believe it was connected with the brake system.

Still no joy
 

Well, my dealer determined that my car didn't qualify for the recall. The chassis number was within range, but the engine number wasn't. I'll appeal to MBUSA.

Ross, my symptoms include the "limp home" event triggering a lot of false diagnostic error codes, with the idle speed switch being commonly triggered. I had mine replaced too, with no joy. Seems common to others on this site with the same problem.

Ricky, the upper engine harness is the same one you had replaced. Apparently there is a lower harness that is part of the car's main harness (I think) and it is much more expensive to replace.

If MBUSA doesn't accept my appeal, I'm not sure what to do next. I could either buy-and-try the EACM, or try for a fresh diagnosis at the dealer or an indy. I'm a little worried about the wiring in the car, even with the engine harness replaced. Although it is happening almost every day now, it seems a sure way to trigger the event is to wash the car. It seems that a few miles after every wash, the car goes "limp". Co-inky-dink or a short somewhere?

Boy, what a pain...but I guess you already know that.

I'd try pulling apart every connector I could (without chance of destroying brittle connections) and re-connecting with electrolytic, or conductive, grease. Prevents any corrosion, and ensures optimal connections.

Just a thought in the hope that it helps:)

Mark,
My sympathies on your problem! I would have sworn, from everything I've read here and on the Easley list, it was the throttle actuator --

I like the above suggestion re: cleaning all connectors. The other thing I'd try is to replace all the fuses. Folks on the "other" list say to replace all fuses at 10-year intervals, and yours is officially 10 years old. Sometimes fuses look just fine but have little cracks and cause weird intermittant problems which defy diagnosis.

At any rate, it's a cheap thing to do.

Good luck to you!

ASR
 

Mark what was the engine # limit for recall?
It seems to me there are enough of these problems that we could start a small class action or get dot to do a safety recall.
Any (shudder ) Attorneys out there?;)

Mark, maybe some fellow LA members can help by donating "swapable" known good parts for a limited time. Just to take the guess work out of the picture?

Mark,

The upper engine harness is the most susceptible to disintegration due to its proximity to the hottest parts of the engine. I've been told many times not to worry about the lower one (and yes, it is a LOT more expensive...)

Now that you mention problems occurring after washing the car, I do recall that something similar happens to me, although it hasn't been too much of a problem for me to tackle it with the same gusto. Everytime it rains, or when the car is washed, (1) the antenna refuses to retract and (2) the passenger side fog lamp dies, triggering the dashlight telling me of a burnt out bulb.

Then there's also this weird problem of some (not all) of the dash and switch lights coming on (a/c vents adjuster, gear selector, rear sun screen, seat heaters etc). It goes away after driving for a while (I could almost swear it goes out after mashing the go pedal in gear but I'm not sure). It only happens when you don't use the vehicle for days. What worries me though is that the lights are on when I get in the car so it can potentially drain the battery.

I know that's not quite helpful but in situations like this, seemingly unrelated symptoms might point to the solution.

Best of luck.

NOT A RECALL
 

Ricky, it sounds like your car is haunted and it misses you if you don't drive it every day! Just kidding.

I spoke to MBUSA customer assistance last night, after hours. I was told that the document I was referring to (MBNA 30/4) was NOT a recall, but a Technical Service Bulletin. So even if my car fell within the range of engine numbers, MBUSA would not be responsible, because my car is out of warranty. After I understand this issue a little better, I'll still appeal that position. Meanwhile, I'll call the customer assistance line on Tuesday during business hours to speak to a technical rep.

My question now is: My car's chassis number is within the range of the TSB, but the engine number is 79 numbers higher than the range. Which is the correct version number EACM for my engine? The version K9 that is installed, or the (later) version K10 that is specified for the (earlier) engines in the TSB? I would assume that K10 is correct, and according to the symptoms that are addressed by the TSB, it appears that swapping to a K10 should solve the problem. Anyone have any knowledge of this?

Meanwhile, I'm heading to the Kragen store for some electrolytic grease and fuses.

I swapped out all the fuses in the fuse block with new ones, and went through some of the connections in the engine compartment with dielectric grease. Then I opened up the CAN box to have a look at my EACM again, because my dealer tried to tell me that it was a Bosch part, not a VDO part. Here's a picture of my EACM, VDO origin, version K9, manufacture date 10th week of 1991. I'm going for a drive tonight. Let's see if the gremlins are still on board!

It wasn't the EACM
 

Sorry this post has been delayed. Some of you have been e-mailing me for a progress report. It hasn’t been positive! The new fuses and connector-cleaning held off the gremlins for five days. That was pretty good, I thought - just long enough to get my hopes up. After the symptoms came back (on light acceleration from a stoplight, level road, heavy traffic), I decided to buy-and-try the EACM. The EACM that was in my car is an original part number 124-545-07-32, version K9, manufacture date 10th week of 1991. The new one is a superseding part number, 124-545-45-32 originally specific to chassis numbers from 840529 (mine is 766858). It is software version K13. I installed it myself. I planned to bring the car in to my interested independent tech to have the remaining diagnostic codes read and the ‘check engine’ light reset. As it turns out, the EACM didn't do the trick; on the 5 mile trip to the shop, the ASR/ limp home symptoms recurred. This may have been because I didn’t know about the reprogramming time required upon reinstallation of the module - 90 seconds with ignition on before starting the engine. But after my tech reset the system, it still goes into ‘limp home’ mode.

I feel like I took some chances, to save some money, by turning to an independent after I got sick of spending dealer-dollars. The dealer was going down the same path I saw others on this forum followed (first the harness, then the idle speed control, then the throttle actuator), so I thought I could see where it was headed. By following the threads here and making my own diagnosis, I gambled that I could spend less installing the parts myself, or having an indy install the parts, but that meant committing to the cost of the throttle actuator and then the EACM, which was purchased at a discount but nonreturnable. I might have done better to stick it out with the dealer, who had offered to do a trial with a new EACM after MBNA refused to warranty it. So with a new harness, new throttle actuator, new idle control, and now a new EACM, nothing has solved the problem yet. The car goes into ‘limp home’ mode just about every day. This morning the car is headed back to the indy, who has been doing his own research. Looks like the next suspects are faults in the CAN bus or the other modules. Any advice out there?

Have you tried the alternator. My E320 went into "limp home" mode when the alternator was on it's way out. Only did it in stop and go traffic - never had problems with it on the open road.

DTC codes. . .
 

where were they read? From the Diag Module or from the EA?

Model: 124.036 1992-93 EA Module (Pin 7 on 38 pin)
7: CAN data bus signal from EA/CC/ISC, ABS/ASR, HFM-SFI or LH-SFI (right or left)
control module faulty.
6: Starter lock-out/backup lamp switch.
2: EA/CC/ISC control module (N4/1) or Safety contact switch (M16/1s1) or Stop lamp
switch or Cruise control switch or Actual value potentiometer or Starter lock-out/back-up
lamp switch or engine speed signal or vehicle speed signal or closed throttle position
switch or safety relay in EA/CC/ISC control module.
96: ???
224: ???

Model: 124.036 1992-93 DIAG Module (Pin 19 on 38 pin)
2:Oxygen sensor faulty
6:Idle speed control faulty
7:Ignition system faulty
17: Data exchange fault between individual control module
96:???
224:???

DTC 7 would cause the problem since the EA must communicate with the LH-SFI directly and others indirectly. Check my page, menu #2 for EA and #1 for overall engine management block diagram.

Hope you can get it fixed soon!

Check Alternator!
 

Mark: I'd like to endorse ENGATWORK's suggestion that you have the alternator checked. Last summer I spent a week stranded in Las Vegas while the dealer puzzled over random fault codes in my E500. The car was in "limp home" mode and going nowhere...

The "technicians" couldn't figure out the problem 'cause the fault codes were wonky. They kept swapping parts in and out with no effect. Finally the service manager noticed voltage spikes and had the alternator checked. New part - problem gone!

BTW - kudos to M-B Roadside Assistance for giving us a Jaguar rental car and putting us up at the Sahara for the week ;)

Thanks, Jim, Jim, and Dean. The tech who is looking after my car had similar codes read, and is currently just clearing, recreating the fault, and re-reading to try to find a pattern. I called him about the alternator spikes, and he is aware of that unit being on the list of suspects. He has been looking at the alternator readouts when the diagnostic unit is plugged in, as I understand it. So far no problem there.

Forget the diagnostic readout on the alternator, have the alternator hooked-up to a scope and measure the amps and voltage under load.

If the power is not clean to the diagnostic module, how can you trust it?

:-) neil
1988 360TE AMG
1993 500E

Mark,

Not trying to encourage you to continue your parts trial and error nightmare, but an Alternator is almost a maintenance item @100k (emphasis on "almost"). What you could do alternately to ensure the alternator is not the culprit, is spray some electrically conductive grease in there (I know there are such products out there) to make sure it's giving you the best, most consistent voltage.

Our hopes & prayers are with you, brutha:)

Limp Home
 

Mark,
My car is in winter storage so I cant speak to the problem currently, but this only happens to my car on full- bore acceleration. There might be a clue in there somewhere.
Best wishes

I'll second Michael on the alternator note. Mine, on the 500E , went out right at 108K... My wife was stranded and we had to tow to the mech.

I'll suggest, for the reasons related to your problem, AND to save yourself a major inconvenience, to replace... ( it is SOOO easy to spend someone elses money :D )

Thanks guys. I'll bring up the alternator issue again with my tech. I think he's reading this thread too. Right now, the current suspect is a faulty shift indicator sending intermittent info. I'll post an update after I get my car back after the latest round.

Dare I say it?
 

Three days and counting, I think my tech found the problem. It was the S16/3 starter lockout and reversing lamp switch (with selector lever position recognition), also called the safety neutral switch. It is an electro-mechanical switch that is actuated by the shifter and sends gear selection information to the EACM, more properly called the EA/CC/ISC module, as I have learned. Part no. M000-545-62-06, $69.00. It showed up on the diagnostic unit as a misread on the shift lever position, that would not represent actual gearshift selector changes. Apparently that was enough to kick it into 'limp home' mode. I got my car back Friday and drove it 45 miles - no problems. I drove it 20 miles Saturday - no problems. I gave it the dreaded car wash test Sunday - no problems. I just might start enjoying this thing again! Wish me luck!

Hey Mark that sound like good news. If it showed it up on a scan, how come not before? Did they have to SCAN a different electronic UNIT?

:-) neil

Knocking on burl...

Neil, Three reasons it didn't show up before:
1 - So many error codes it got lost in the clutter. That's why I needed to replace the harness, etc.
2 - My tech brought in a consultant to review the problem - a guy named Marty from Luxury Motor Vehicle Information Systems (LMV Info). Marty put a different diagnostic unit on it. Marty's unit was laptop PC based. It could read more inputs live than the error memory stored, so the generalized error codes could be broken down into specifics.
3 - The shift selector error only showed up as a live error, while the car was running.

This, of course, is as I understand it as a layman.

And Michael, yes, I knock the burl every time I start it!

Mark,

Great to here your car is back to normal. Isn't it the most rewarding experience when you have worked out a problem. The best part is that you have checked so many electrical components you shouldn't have to worry about this for a long long time....Have Fun!!

Placo1

Interesting. Do you know if the MB HHT (Hand-Held-Tester) was initially used or something else?

Also, was the PC-unit the official MB STAR PC Diagnostic system, or some aftermarket unit?

Again, congrats, and knock, knock . . .

:-) neil
1988 360TE AMG
1993 500E

Great!
 

I'm sure you're glad that it's fixed!

Note that the #6 code showed the real fault but ". . it got lost in the clutter". The 'live' feature of some scannrers is nice to have when this type of failure occurs but it was diagnosed without it.

Anyway, enjoy that great car!

Placo1, what I learned is that there are more than a dozen inputs that can cause the car to go into 'limp home' mode, and the diagnosis is difficult - part experience and persistence on the part of the techs, and part best available tools. So I don't feel confident that something else won't fail! I'm just more prepared to deal with it.

Neil, I do believe the first tool was the HHT. It was small and housed in yellow plastic, like a Fluke meter but fatter, if I remember correctly. I don't know the manufacturer of either unit. I'll ask.

JimF, the paperwork from last week's session reads in part (1 of 6 error codes still present last week): "CODE FROM D. M. DIAGNOSTIC MODULE PIN 19 - CODE 6: Idle speed control incorrect, fault from EA/CC/ISC" So only after I reminded Marty and my tech that the idle contact switch and the EACM (EA/CC/ISC module) had already been replaced did it lead further to the real culprit. They still wanted to replace the idle contact switch again. I'm interested in your comments on this.

Of side interest to JimF - one of the other error codes: "CODES FROM LH DIAGNOSTIC MODULE PIN 4 CODE 3: Engine coolant temperature sensor short or open circuit." I assume that's the added resistor keeping my engine cool, right? ;{) Without it, I would have been frantic with the amount of time the car sat there idling through all this exercise!

Also, I might add, that only because the part degenerated enough over the last several months that you could pretty much cause the event to happen every time you ran the car, could it be found "live". So I don't feel like anyone wasn't doing their job! But it was my tech's persistence that I credit with solving the problem.

Thanks again Mark.

When you ask about the HHT or HHT equivalent, also ask about the PC/Laptop used.

I heard MB is selling their STAR Diagnosis System supposedly only for IBM ThinkPad's at $20K/each, not including PC

:-) neil

Neil,

The handheld diagnostic unit used on my car is a Baum CS2000. The unit that Marty of LMV INFO brought in is the Mercedes STAR Diagnosis System.

Mark- that's good news. Is Marty of LMV INFO an independenet MB mechanic?

If so, where is he located. It's nice to know of an independent who has invested in some of the more esoteric tools.

:-) neil

As I understand it, Marty is a trainer/consultant, giving seminars and consulting with a network of member shops. He's a former MB tech.

B11/2 is the ECT sensor . .
 

but my CH affects the B10/8, CTS (Coolant Temp Sensor). My mod does NOT affect the LH-SFI in any manner. For backup info, please read the MS thread:

http://www.peachparts.com/shopforum/tech-help/16757-how-change-aux-fan-cut-point.html?highlight=CTS

DTC #3 is differentiated from DTC #2 in that #2 points to the one side of the sensor whereas #3 points to the other side of the sensor.

The resistance values for this sensor vs temperature are:

Temp(C)--Temp(F)-------- Ohms
20 --------- 68 ----------- 2500
30 --------- 86 ----------- 1700
40 ---------104 ----------- 1170
50 ---------122 ------------ 830
60 ---------140 ------------ 600
70 ---------158 ------------ 435
80 ---------176 ------------ 325
90 ---------194 ------------ 245
100 ------- 212 ------------ 185

Both sides should track each other and be within 5% of each other. If not, then it needs to be replaced. Glad the CH kept you car cool during extended idle time.

new thread: Intermittant 500E ASR problem
 

Rather than clutter this thread, I've started a new thread, "Intermittant 500E ASR problem" here:
http://www.peachparts.com/shopforum/tech-help/39898-intermittant-asr-problem-1993-500e.html

I'm giving notice here for better visibility.
In short, I only get it during startup (sometimes), and so far only during a cold start or when the car has been sitting for at least 4-hours. Yes it goes into Limp Mode. Disappears after a restart.

Please respond to the new thread:
http://www.peachparts.com/shopforum/showthread.php?threadid=39898

Thanks,
:-) neil
1988 360TE AMG
1993 500E

94 SL500 ASR/limp home mode
 

We have the same problem with 94 SL500 with 60K. A wiring harness was replaced and it still died. It wouldn't put off any code. Installed a new air flow sensor, but problem persists. Still no codes. Any advice appreciated. I'm brand new to this site and I'm not sure how to find all responses. I'm at FrancisDalton@aol.com and MaurAdler@aol.com

Thanks, Frank Dalton