93 400E asr light Limp mode - PeachParts Mercedes-Benz Forum

Chris Dvorak · #1 12-09-2005, 03:24 PM

I have read most of the old posts reguarding the ASR light and Limp mode.
My car has had 4 episodes of the ASR variety the last three in the last week or so. It clears out and runs fine after tuning the engine off. I had one instance where the car would not run, but after being towed to a repaire shop
would run fine. Is there a way to tell if the problem lies in the wirring harness, electronic throttle actuator, or the misc switches like the brake light switch.
It sounds like the codes need to be read. Can one use a generic auto shop variety code reader? Is there any new information on this subject?
Thanks Chris

deanyel · #2 12-09-2005, 08:58 PM

Next step should be to read the fault codes, by building the Arthur Dalton code reader, on which there is more information in the archives.

pcmaher · #3 12-09-2005, 10:57 PM

Certainly pulling codes is a good place to start. You need to keep in mind that if wires are shorting out within the ETA harness, you could get all sorts of weird, meaningless codes. Intermittent shorting is a definite possibility, because the bundle flexes and is subject to varying temperatures, vibration and loads. I would suggest CAREFULLY cutting into the wire bundle of the ETA, and examining the condition of the insulation. Although the following links are specific to a V12, the basic problem is the same...

http://v12uberalles.com/throttle_actuator_rewire.htm

http://v12uberalles.com/MAF_rewire.htm

ebennz · #4 12-10-2005, 11:25 AM

do not cut into wiring harness without first cutting your own throat, DO NOT let that "jeannie out of the bottle"!!

you can check parts of it without cutting.

what is cars mileage and maint history?

how are plugs AND plug wires?

how old is your fuel filter?

have you replaced caps and rotors recently?

have you replaced main engine wiring harness?

do you let your gas tank get WAY down before you fill up?

i've asked a few questions, eh?

more of your maint history may help...

pcmaher · #5 12-12-2005, 08:19 AM

Ignoring a well-known issue (crumbling/cracking wire insulation) on these cars is not good advice. All possibilities, however unpleasant, must be investigated. Certainly start with the basics as ebennz lists, but cap and rotor replacement is not likely to fix ASR / Limp Home problems.

JimF · #6 12-12-2005, 12:11 PM

Quote:

Originally Posted by Chris Dvorak

I have read most of the old posts reguarding the ASR light and Limp mode.
My car has had 4 episodes of the ASR variety the last three in the last week or so. It clears out and runs fine after tuning the engine off. I had one instance where the car would not run, but after being towed to a repaire shop
would run fine. Is there a way to tell if the problem lies in the wirring harness, electronic throttle actuator, or the misc switches like the brake light switch.
It sounds like the codes need to be read. Can one use a generic auto shop variety code reader? Is there any new information on this subject?
Thanks Chris

Since your car is very similar to mine, check out MENU#24 on my web page. You are experiencing the same symptoms I had.

Reading the DTCs from the following modules; EA, ABS w/ ASR and Diag Modules. The latter can be read using the car's LED/Sw combo (X11/21s1) shown in MENU#2.

If you find DTC #6, (ISC Faulty) in the Diag Module, you can be assured that it's not the plugs/wires/rotors . . . . unfortunately.