Originally Posted by jrodnar

i started having a problem with the asr system on a 1992 500sl. I was driving on the highway when the asr sensor light came on and the car defaulted to a "limp home mode": The engine output power was reduced and i was able to make almost home; after exiting the highway and reducing speed a red light, the battery light came on, and the car completely stalled completely. I restarted the car and the asr light was off and the car drove normally home.

The local mercedes shop i use (not a dealer) replace two motors relating to the asr system: Part # 0005453165 -$ 1,500 parts & labor. The car was running fine for two months then the asr problem returned. The repair shop then replaced the asr sending unit: Part # 0005401417 -$ 720.00 parts & labor.

Days after the sending unit was replaced the asr problem continued to occur sporadically. The shop then told me it was the main computer causing the problem, the installed the electrical accelerating unit: Part # 1295450132 - $ 2,160 parts & labor. In the hopes that the computer would resolve the problem i agreed to the cost. After picking up the car and driving out of the repair shop for a mile the asr problem returned. I called the shop and returned the car, told them to remove the new computer since it did not resolve the problem.

The original electrical accelerating unit was reinstalled and i was credited for the cost of new computer module. The over voltage protection relay was also tested with a new unit but the problem persisted.

Without any other repair or testing, the owner of the repair shop told me he drove the car during the week without the asr triggering once. I picked up the car on friday, march 4, 2003 and a mile from the repair shop the asr console light came on, the car began the asr “limp home mode” process; reducing motor output power and when the car speed is reduced below a specific speed,20-25 mph, the battery light comes on, and the car completely stalls. This happened five times before i was able to make it home - i have to turn the car off, restart the car the light goes off, few minutes later the light comes on again and i have to through the same process to restart the car.

I don’t believe the repair ship did a thing during the time the car was at the shop; they also informed me that the asr module was only install in the sl for two years 91-92 and then discontinued, and that mercedes has very little technical information on repair procedure for the asr in this model year. I know that that’s a lie; i’ve seen the asr system on all sl since 1992.

I think that they either now know what is causing the problem and realized they changed parts arbitrarily and don’t want to honor the repair warranty by installing the correct parts, or they don’t have the technical expertise to isolate the problem: They changed unnecessary parts at will in the hopes that one of the parts will resolve the asr problem.

So far i’ve spent over $ 2,220 in parts & labor and the asr problem is the same as the first time i took the car to the shop. I am temped to take the car to an authorized dealer for repair, but i think the shop should fix the problem or refund me for the work i’ve paid to date. I am taking the car back to them on monday.

I posted the above in the sl forum, and i received replies indicating the problem may lie with the wiring harness; probably another expensive pieces of hardware.

Have your come across an asr problem system similar to mine?, and why would the battery light be an issue with the asr system? Could it be a battery, alternator voltage problem?

Any information could you provide would be greatly appreciated.