asr question

[944s2c]

Hello , I have a weird asr problem: car goes into limp mode after about 1 hour of driving....I do not get an ASR light! Turning key off then on temporarily fixes the problem.Further investigation reveals throttle actuator arm ratchetty especially @ WOT.,I tested system by leaving key ON and periodically checking the rotary out put of the throttle actuator . The output slowwly decreases until it doesn't move at all !Any helpful hints would be greatly appreciated!Thanks,Dan

p.s. 1991 300e,I believe this is 1st generation ETA system.









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[944s2c]

Still trying to troubleshoot this problem.I have the service CD and the test proceedure but I don't have the harnness or the socket box tester.I THINK it's the throttle actuator but would like to confirm before spending the$$$$. I've had this problem for over a year and initially replaced the throttle pot at the suggestion of a local MB tech. They said if this doesnt fix it that it's probably the actuator.Any help would be really appreciated...thanks,Dan

[400E]

Dumb question, but you do have ASR, right?

If so, does your ASR malfunction light actually work -- i.e., does it light up when the key is in position 2?

Have you searched on this? Even if you don't have an ASR malfunction light on, do a search on 'asr light' and you can learn a lot about the system and its malfunctions.

Lastly, you eventually will need to pull the codes. It's a complex system with a number of possible problems which can cause mallfunctions.

[944s2c]

Steve,thanks for the reply.Yes the ASR light comes on when key is in ON position and goes OFF when engine is started.So I presume the system is passing the self test.To further trouble shoot this problem,I removed the fixed rod from the throttle actuator and connected it between the throttle crank and the throttle plate ,thereby creating a purlely mechanical linkage between the accelerator pedal and the throttle plate.I have driven the car in this configuration for some time now with the following observations:when on snow,the(!) light comes on and system applies rear brakes to reduce wheel spin.When wheel spin is reduced the (!) light goes out.This seems like normal SYSTEM operation, just no throttle reduction (throttle actuator is mechanically disconnected)The system will reduce throttle inputs when the actuator is connected.My problem is the actuator is only rotating about 50 degrees when it should be rotating about 90 degrees.The tech I talked to said since this is such an early system,there's no codes stored and must be diagnosed with a socket box tester ,harness adapter and VOM. Any help with this would be really appreciated! Thanks, Dan

[400E]

Well, you've tapped out my very limited knowledge of this system. Mine has intermittently thrown an ASR malfunction light, while driving with the cruise on, and only after doing so for several hours of driving. If I pull over and restart, it will reset and all will be well for a while. Has not happened when cruise control is not on.

Hopefully one of the professional techs will weigh in on this...

Or one of the non-professionals. I do believe someone (Arthur Dalton, maybe?) posted some pics of his dissambled throttle actuator within the last 6 months or so -- might be worth a search.