Engine symptom and cause?

[KeninSD]

I am experiencing a problem on hot days after the engine sits a while after running.

The ASR light comes on and then 95% of the throttle action occurs at the last 5% of the accelerator pedal. Also the trans doesn't shift until I let off the gas. It goes away the next day after cooling off and reoccurs after being hot for a while.

Is this: A. Upper engine harness problem?

B. Electronic throttle unit problem?

C. Something else?

Thanks for your sharing of experience/knowledge.

Ken

 

[gsxr]

Sounds like you are experiencing the infamous Limp Home Mode (LHM). It may go away (temporarily) if you turn the car off and re-start the engine, even when warm. Time to pull codes, clear codes, and see which ones return.

Quite likely to be either the engine harness or ETA; if both are original. If the harness is original, inspect it closely, if there is any sign of cracked insulation order a new one ASAP. If the harness has already been replaced, the ETA is the next suspect....

 

[KeninSD]

Thanks Dave, I have an upper harness awaiting installation after the first signs of trouble with the existing one (might be original). I am hoping it is not the ETA as I don't have a replacement. I've been avoiding replacing the harness so as to get the max life out of it and also these days when I work on the car I wind up breaking all kinds of little plastic parts! So it sits waiting for some TLC.

 

[gsxr]

Sounds like this is your cue to replace the harness ASAP. There is often a date code on the tag of the harness, near the big connector behind the CAN box... this can help identify the harness age. At least, all of the harnesses on my cars have this. It may be a large tag on the thick cable, or a small tag on the single wire to small round connector right behind the large connector. Anything dated 95 or older is almost certainly original.

 

[KeninSD]

Today I replaced the upper engine harness. Not a particularly difficult job, but some very tight spots nonetheless, #1 fuel injector plug notwithstanding.

Little plastic clips/holders/plugs crumbled all around me as I unplugged the old harness. I noticed the other harness that follows the same path through the firewall was in terrible shape with exposed copper and crumbling insulation.

When I started the car the problem still persisted. However, this time I heard a noise coming from the drivers side of the throttle body. It sounded like a little electric motor running with bad bearings. Depressing the throttle to the floor (engine not running) caused the noise to stop. Is this the other common problem (ETA failure) that happens to these cars?

 

[gsxr]

ETA failure is semi-common... it's not unusual, but nowhere near as bad as the engine harness issue. I'd guess than 75% or more of M119's have already had their harnesses replaced (or, are in dire need of such) while maybe only 30-40% have needed to have the ETA repaired/replaced.

The ETA does make some odd noises when you turn the key on and leave it on for a few minutes, clicking & whirring, etc. This is normal. However if the noises become noticeably louder or different, that would seem to indicate an ETA on the way out. I've not yet heard much about this, usually the failing ETA either throws random codes, and/or triggers a random limp-home mode.


ig:

 

[KeninSD]

I disconnected the battery, let it sit awhile, then hooked it back up. The ETA stopped making noise, but the ASR light is still on and in LHM. I have the 92 LH module in it so I guess some things are not reset. So,could it possibly be the sensor on the transmission and/or the switch on the brake pedal as well as or in lieu of the ETA? Probably not, but it is time to start ruling out stuff.

 

[gsxr]

The '92 LH won't have the fuel trim reset when you disconnect the battery, but that doesn't affect anything else, and wouldn't be related to the issue you describe. It's time to pull codes, clear them, and see which ones return immediately. That will help you identify potential causes. It is possible that one of the switches you mention could be at fault, but it's easier to check codes than throw parts at it...

 

[KeninSD]

I agree, but the highest order of electronic diagnostic tool in my toolbox is a volt/ohm meter, so I think I'll have it flatbedded over to my friend's uncle who has all the right tools to pull codes, diagnose it and tell me which parts to throw at it and in what order.
I hope it is just a sensor and not the ETA!

 

[KeninSD]

While doing research today, I discovered that my ETA cable was run incorrectly through the firewall. That and the fact the cable looks much newer leads me to believe that the ETA has been replaced once already. Also, here is a pic of the tag on the upper engine harness...yup, original.

 

[KeninSD]

Well, the guy who read the codes says the codes tell him my ASR control unit has failed. He also says the ETA may or may not have failed as well and that it is possible that the ETA caused the failure of the ASR control unit. He is hesitant about putting in a replacement ASR unit for fear if the ETA caused the failure it may break the replacement unit as well. Any suggestions? Where do I get an ASR control unit?

 

[gsxr]

Hmmm. Well, if true, that would be the first time I've ever heard of an ASR control unit failing. I would try to get your hands on a different unit (borrow from another car) and swap it in. It is extremely unlikely than an ETA problem would damage the ASR module, I wouldn't worry about that. What should be done is to clear all the codes, verify they are cleared, then start/drive the car and see which codes return immediately. Any chance you could get a list of the codes from each module?

As far as sourcing a replacement module, forget buying new unless you're independently wealthy. Good used modules should be cheap due to low demand, and since they were also used in the 400E/E420 and 500SL/SL500 (1993-1995), there are lots out there. P/N is 013-545-39-32. Looks like there are plenty out there for ~$100/ea. Drop me a line if you need help locating a source for used ones.

I still doubt this is your problem, would really like to know what the codes are...

 

[KeninSD]

Thanks for the great reply. I agree. I'll get the codes, I don't remember what they were. The problem was so typical and really influenced by heat that I think it is the ETA or at least the ETA cable. I might replace the neutral safety switch just for good measure as well. Check out these videos, especially the first one and the one at the bottom of the page, very interesting.
http://www.restoreyourmercedes.com/Mercedes%20throttle%20body%20rewire.html

I was also looking at Jim's page: http://www.k6jrf.com/MB_asr.html

 

[gerryvz]

I agree that a failed ASR module is extremely rare, and that a broken ETA would not permanently (electrically) damage an ASR control unit.

As for other potential causes of limp-home mode: there are specific codes that indicate bad wheel sensors (which are for ABS and ASR) and these actually go out with a fair amount of regularity -- sometimes they just need to be cleaned.

Did you get what the codes were? Can you call the guy and ask him?

There's no reason to replace the neutral safety switch unless there's a code that indicates that it's bad. And there is a specific DTC code that details that part as bad.
The neutral safety switch isn't likely going to throw the car into limp-home mode. More likely a bad NSS won't let the car start and/or let you move it into and out of gear readily. And generally a failing NSS will let you start the car in Neutral -- the Park starting mode often fails first. Furthermore, you can jump two of the four terminals on the NSS with a wire to bypass it, and this can be done in about 15 minutes. If you do this and the car still has the limp-home mode problem, then you know for sure it's not the NSS. But typically you'd already know that.

Must....get.....those....code....numbers......
Then report back here.

If it is your ETA, my best advice is to shell out for a new unit from MB through parts.com rather than buying a "used" one.

If your harness is indeed original, there a DAMN good chance it could be that. It's definitely a candidate for replacement no matter what. Again, parts.com is your friend on this to get it most cheaply.

Cheers,
Gerry

 

[KeninSD]

Thanks Gerry, Ill forgo the nss for now (unless that code was there) and I think he did mention something about the front wheel sensors code but discounted it because it didn't affect the ABS part of the system, only the ARS part. I am going there tomorrow and will get all the first codes and whatever repeated codes exist as well. Man, it looks like replacing the ETA involves removing the top part of the E500E specific manifold because I can't see how you could get it out of there any other way.

 

[gerryvz]

Sorry for my tone (not directed to you) ... but who is this mechanic anyway? Is he a Benz mechanic? Absolutely ABS and ASR share the same system -- wheel sensors, control module, and so forth. The sensors are how the computer gets the data as to whether the wheels are spinning or not and thus whether to reduce power to that wheel or pulse the brakes (depending on the system). It's also why when you disconnect a wheel sensor to disable the ASR (for example a quick fix for drag racing or dyno work), you have the ABS and ASR lights go on on the dashboard and the system throwing a code for that wheel sensor being defective.

If I remember correctly, there is a recent thread here on the board about removing the ETA and it's not the easiest job, but I think it is possible to do it (it's a tight fit, but you can wiggle it out). There's a very good chance if it's not your wiring harness, then it's your ETA. But....codes first. A methodical approach is better than throwing [expensive] parts at the problem. You're pushing $2K to get both parts new, and if it's only one of those you're going to save many hundreds of dollars.

If it DOES turn out to be your ETA, there are going to be a few soft parts associated with it that you're going to need to replace: vacuum lines routed through the area (cheap); the rubber sleeve that goes underneath the mass airflow sensor (these get very hard and brittle with heat+age); and the multi-jointed flexible tube that goes from the ETA to the cam cover (this also gets fossilized with heat and age). You can get rebuilt ETAs with a warranty on them from Beckmann, I believe for around $750; and a new part from parts.com last time I checked was around $900 give or take.

Cheers,
Gerry

 

[gsxr]

FYI, you can get your ETA rebuilt for ~$300 on a budget - details here:
http://500eboard.com/forums/showthread.php?1751-ETA-part-number

Alternately, Doran has one for sale at the moment (late style), and is open to offers:
http://500eboard.com/forums/showthread.php?1838-ETA-92-LH-module-OEM-car-cover

Note that there are early & late ETA's, so make sure you get the correct one for your car. The connector is completely different between the two. The break was somewhere in mid/late 1993 model year, at engine number 7765/7766. The ETA comes out of the intake manifold in only ONE position, and it can be a real bear to figure out the exact orientation. And once you get it out, you'll have the same fun putting it back in, lol. Not difficult, just tedious. Don't forget to order a new gasket and have a tube of Hylomar to stick the gasket to the ETA, then use blue threadlock on the bolts. The factory procedure is at this link:
http://www.w124-zone.com/downloads/MB CD/W124/w124CD1/Program/Engine/119/30-1262E.pdf

 

[gerryvz]

FYI, you can get your ETA rebuilt for ~$300 on a budget

Now that's what I call "Ballin' on a budget" !!

 

[KeninSD]

Gerry, I think he was dismissive of the wheel sensor codes because the ABS light never came on and there were no codes indicating ABS failure. He is a good guy with a long history of Mercedes repair, but now runs a Jaguar shop, so he has been away from Mercs for a while. I put in a new harness post-mortem but it didn't solve the problem. I noticed the ETA cable was run incorrectly thru the firewall so it has been messed with at least once already. I agree about the likelihood of the ASR module not being bad, but the box that runs the electronic throttle may be affected (based on the restoremercedes.com video), We'll see when I get the codes. Dave, that used ETA is very tempting because of the price, but I'll never want to do this repair again so if I can find a new one at a reasonable price I'll probably go for it instead. As far as removing it, I couldn't even see where the bolts were to unscrew the darn thing, very frustrating. I am just thankful I can go to the guy where my car is and intelligently discuss the potential route to solving the problem because of the information provided from you guys here! It will be interesting to see what the exact codes are and I'll report back to you.

 

[KeninSD]

Scan printout.
Man, I don't know what to believe now.

 

[gsxr]

Uh-oh. He's using an aftermarket scanner which is interpreting the codes incorrectly. *sigh* Most likely those descriptions are for newer versions of ASR/ABS, not the version used on our W124's. From the factory docs (click here)...

ASR Code 13 = Stop lamp switch (S9/1)
ASR Code 17 = Battery voltage too low
ASR Code 30 = CAN data bus to EA/CC/ISC control module (N4/1), interrupted

Code 13 could be legit, if it comes back... might need a new stop lamp switch (or, it needs adjustment)
Code 17 is probably irrelevant, I doubt it will return after clearing
Code 30 is a generic fault code that tends to appear frequently with other codes. In general, it can be ignored.

He needs to pull codes from the other systems too; especially the E-GAS module (which controls the ETA). Codes should be pulled from all 6 main systems: ABS/ASR, LH (fuel management), E-GAS (ETA control), DI/EZL (ignition), BM (basic module), and DM (diagnostic module).

 

[KeninSD]

Could it be the numbers are wrong and the descriptions right? It says front left solenoid and rear left solenoid.
Yesterday he said it diagnosed a 6 and an 8. If you look at the DTC page for ASR 6 & 8 are the left front & rear solenoid valves. I think he may have mistaken the diagnostic module for the ASR module because he said it said idle speed control and engine coolant temp sensor had open circuits. BTW, is there more than two temp sensors on this car? Would a bad stop lamp switch put the car in LHM?

 

[gerryvz]

Dave is 100% correct. You need to get codes pulled from all of the modules to provide the full picture.

Just FYI - I had a code 30 on my ABS/ASR module in my recent go-around with the non-start condition (see thread here: http://500eboard.com/forums/showthread.php?1776-E500-difficulty-starting-any-thoughts)

I think the stop-lamp switch is actually rather common. I've had that code many times and to my knowledge it has never meant anything.

The combination of the Code 17 and the Code 30 is interesting. Given the electrical troubleshooting that I recently did with my own car, which had communication problems between modules in the CAN and kept tripping the codes correlating to the fuses & power supply in the Base Module, you may have an electrical issue. When you see codes pointing to similar things (in my case it was electrical & communication issues) you can start narrowing things down.

The low battery voltage to me is the most interesting. Is your battery new? If not, is it holding a charge (say +12.5 or more volts overnight) and 13-14 volts while running? A weak battery can cause all sorts of codes. And as you can see from my problem, I had starting issues and inter-CAN communication issues (like your code 30) as a result of the small adjunct cable attached to the positive battery terminal not being cinched down as snugly as it should have been. As is in my own description, my own car momentary (for about a 1/2 second) tried to go into limp-home mode, then ASR and ABS lights lit up for about 1/4 second, and then things returned to normal as contact was re-established at the positive battery terminal.

So I would really check your battery voltage, your battery terminals, your fuses and your ground points (i.e. at the negative battery terminal where it attaches to the chassis) and under the hood at the strut towers and near the CAN box) for corrosion and loose connections. That is a really logical place to start. Also I'd take your car back in to the guy and have him pull and then clear the rest of the codes from the other modules, and then drive the car and see what returns.

Cheers,
Gerry

 

[KeninSD]

Thanks Gerry. The battery is in great shape. No telling what the connections are like, though. They look fine, but looks can be deceiving when it comes to electrical issues. I did have a bad contact on a fuse recently that shut down the instrument cluster. A little rubbing cleared that up. I think I'll clean all the contacts I can find just as a maintenance item anyway; this model seems to need it from time to time. Would a bad lower harness cause any of this? Mine looks like crap with insulation crumbling off so i ordered one from parts.com last night.

 

[gerryvz]

Batteries can LOOK great (even fairly new ones) but it's best to check them with a multimeter after sitting overnight as well as during running, to ensure the alternator is keeping it up to snuff.

A bad lower harness can definitely affect charging and contact, yes. I actually had the lower harness on my 560SEC go bad (which on that car is somewhat similar to the M119) though not by the insulation issue but rather heat/age. And the issue it was causing was a faint glowing of the battery light and reduced charging capacity. The cable was about 2/3 cut just from age and vibration from the engine flexing on its mounts.

This lower cable connects the alternator, starter, etc. Good proactive replacement.

Cheers,
Gerry

 

[gsxr]

Bad lower harness should not cause any issues with ABS/ASR or ETA. Lower harness could affect the starter, alternator, and oil pressure/level sensors.

 

[gerryvz]

I don't agree Dave. My bad lower cable on my SEC (which had a bad connection at the alternator that was only providing partial contact) did cause all of the lights on my dashboard to light up faintly and glow. Bending/tweaking the cable caused slightly better contact on the cable but the vibration of the engine on its mounts quickly caused the partial connection again.

Essentially, the car was running gradually more and more on the battery due to an incomplete charging, and this caused the glowing lights on the dash.

For the E500E, given the voltage sensitivity of the computers (and my non-start situation is an example of that), I don't think you could rule a bad connection/cable/ground out for the ABS/ASR module. A bad signal could certainly affect operation of the computers. Not saying this is the problem with Ken's LH mode, but certainly electrical foundation is something worthy of checking.

Cheers,
Gerry

 

[gsxr]

Gerry, you had additional symptoms which indicated a problem related to the alternator and/or lower harness.

KeninSD does not have anything resembling those symptoms, which is why I don't think it's likely in his case. A simple voltage check at the battery with the engine running, with a $5 (on sale) Harbor Freight meter, would help answer that question.

Now if after clearing codes, the "low voltage" code kept recurring, that would be a stronger indicator of an electrical supply issue.

 

[KeninSD]

Can you imagine how much more awesome these cars would be if they came with good wiring from the beginning!? We'd be behind the wheel instead of under the hood.

 

[gerryvz]

You can thank the "Green" movement and the German government's kow-towing to the greens/libs for the "biodegradeable" wiring harnesses that used a soybean-derived sheathing for the wiring.

 

[KeninSD]

Well I'll just fry up the old harness and cover it with a little red sauce for a delicious meal then.

 

[KeninSD]

Follow up

I sent the ETA to be rebuilt for $279 at the place mentioned in other threads. Highly recommended. Car runs great now, smooth, powerful, etc. It did run rough on the first start up but then smoothed out the next day.

Im looking forward to see if any fuel mileage improvement occurs. It was getting pretty bad, in the 12s and 13s. It feels like I need way less foot on the pedal to get the same result now.

The helpfulness of the board members here is an invaluable resource to any e500e owner. You are very much appreciated.

The next project will be replacing the lower engine harness, which looks like an unpleasant but necessary job.