Hello All,
Today when I started my 1993 400e I noticed a problem. The car had been sitting in the cold for 2 days and this was the first time I started it. When I started it, I noticed the "ASR" light was on, which alarmed me to say the least. When I tried to drive, the pedal did nothing until it was almost floored. I would say at 90% down before I got any reaction. I thought it might be transmission related, because also when I was driving the shifting was off too. However, I turned the car off and on twice. After 2 tries, the car worked fine. I figured this is some sort of electrical problem, but I don't know where to start. I had to leave my car down in Blacksburg and take my brother's car home, because I didn't want to risk further damage. I would like to try to diagnose the problem here so I can find out if any shops down there are capable of doing the work, plus I don't want them to try to tell me its something else and charge me up the ass. If anyone has experienced this or knows what it is, please let me know. I already changed out my engine wiring harness 2 years ago, which had caused electrical problems in the past, but this I have no idea. Also, I normally change my oil myself, but I didn't have time before this road trip and took it to a shop. This was the only thing out of the ordinary, and I can't think of anything near an oil change that could do this, but I figured I'd give a recent history in case the events are related.

That's the limp home mode - caused by the ASR system. Try a search - lots of info in the archives. Next step should be to read the fault codes on the 38 pin connector. You can build a code reader and do this yourself. Try a search on this too.

When you get codes , see if you get one for Brake lamp Switch...common fault.
But check codes first.

This one "ASR" light being on can cause all of these problems? Since I am not with my car, I was just going to take it to the dealership in Christiansburg. Is this something they should catch immediately when they check the fault codes? Or is it something any mechanic with the ability to check fault codes should be able to identify and fix easily? Since I left my car down there (I had to be home early), what is the best way I should go about getting this fixed by someone else? Thanks for the helpful responses deanyel and Arthur Dalton.

The ASR sytem has gone into LIMP mode. So, a simple fault can cause all these problems. The codes should give the mechanic an idea of what triggered the ASR system to go into LIMP. Could be as simple as a brake lamp sw or NSS sw..... But rather than guess , get the codes yourself [ owner access under hood, check Archieves] or have it done. The diagnostics system will most likely have detected a fault in the system and should have that code stored to give diagnostics direction...

Here is a site that has your chassis ASR related codes..go to pages 3 and 57/58.
That will at least give you some ammo when they tell you what codes they pulled. [ if any].. This will also give you an indication of what we are talking about. Thumb through it........

http://www.geocities.com/MotorCity/Downs/1039/mercedes/cs1000_mb.pdf

Beware that many dealers seem to come to the immediate conclusion that you need a new throttle actuator for a couple thousand dollars. You're just much better off if you read the codes yourself. Of course there's a chance you need a new throttle actuator but more likely it's something less serious.

I've gotten some new information on this problem. The ASR light (and resulting loss of acceleration) will not occur once the car is running, except a few instances. If the breaks are slammed, or the car loses traction, the ASR light kicks on and the accelerator only has power near the floor, no response for the first 90% of pedal. I took it to Luxus, which is a very well respected shop on this forum, and he has not been able to determine the problem. The codes show up when the problem is there, but when the ASR light is not on, the codes don't show. I believe the code is saying throttle actuator, but I'm hoping thats not it. Any other guesses? Does this ring any bells?

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That is what ASR does ..The ASR light comes on to tell you ASR is called for/working and a sig is also sent to the accelerator to limit engine torque to the drive wheels.....
Does it go back to normal operation [ ASR light goes out] if you let up on the gas ..???

The problem will not right itself without shutting the car off. After taking it to Luxus in Manassas, he thought it was the valve lifters getting stuck. This seems to make senes, especially since the ASR light will go off after the car warms up. The longer its been since I've driven, the more chance there is of the ASR light going on and being a problem. I was using the recomended 10-40 Mobil One oil, but I'm thinking of taking some out and adding some thinner oil. If you, or anyone else, has any ideas on how to clean up my valve lifters, I'm all ears. Thanks.

It sounds like something far less serious than valve lifters. Did the tech even bother to read the codes?

They'd better be sure - dang sure - before raising the alarm like that.

ThillyGooth

Please go back and re-read the posts above - you have gotten some excellent advise.

You need to have a competent tech "read the codes" so you do not get taken advantage of and have expensive work done which is not going to fix the problem.

As others have said, this is a fairly common problem (one which I had myself and it did turn out to be a $25 brake lamp switch) - but the only way to know is to have someone who knows MBs do the right thing and snag the fault codes.

__________________
Steve
'93 400E

ThillyGooth, you certainly have received great info . . .

If you want to see what happened w/ my "ASR" problem including codes, please read MENU#24 on my web pages.

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Regards . . . . JimF
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'94 S500 Cpe

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