ASR light comes on...loss of power
 

On my 500 sel (1993) ASR light comes on randomly accompanied with loss of engine power. Only if the engine is turned off and restarted does the light go off and then engine runs normally, until the next random episode occurs. This seems to happen freuently at driving constantly at high speed, i.e. on the freeway. So far has not happened in city driving.
Dealer cannot diagnose this problem and has replaced computer at cost of $3000. Another mechanic has changed throttle actuator at cost of $1000. Still have same problem.
Anyone seen this problem and any ideas?????????

what codes? have the speed sensors been checked? harness ok, base module ok? which control unit? E GAS?

I've seen this before and have seen bad EGAS's, bad EA's and bad base modules along with bad speed sensors. I had 1 that the harness from the r'h speed sensor had been chewed by a rodent and it would short to the inner fender. I had another one that the customer had done his own brake job and had the speed sensor harness mis routed and rubbing on the control arm until it grounded out.

I've heard of bad exciter rings on the front hubs, damaged rear speed sensor harness's and so, it just needs a through check prefably in a failed state, in other words dont cut it off once it is failed, this way the system dosent reset and diagnosis is a bit easier



Joe

How's your alternator/bushings looking? How many miles on your car? A bad alt could sent a voltage spike causing a problem in the computer.

My 500E went into limp mode and it turned out to be a $10 brake light switch that was causing it...that and the alt was one the way out at 130,000 miles.

Do a search under "limp home" and "asr"
This is a known problem which seems to have many potential causes.

don't know condition of alternator but will have it checked out. Car has 126k miles.