Intermittent Mercedes ASR light

I have a 1995 Mercedes Benz E-320 wagon. The problem is that the ASR light, which indicates that the vehicle is experiencing wheel spin, comes on very frequently particularly when the outside temperature is lower than about 70 degrees. When I start the car on a cold morning, the ASR light immediately comes on before I even shift into drive. You absolutely cannot move the car while the ASR light is on. If I am lucky enough to get the car started without the light coming on, it will come on less that five minutes later as I brake for a stop sign inside my neighborhood. Note that the engine temp is still cold, under the 80 degree mark.

However if the car sits idling in the driveway for 10-15 minutes and has reached the 80 mark, I rarely have a problem with the light coming on driving to work. Again please note that this happens most often when the air temp is cold.

Though during the summer, the ASR light rarely comes on. Only after an occasional rain that brings a cold front does the light come on.

What could be the problem? There are so many variables that affect the light coming on: air temp, engine temp, brake action, etc. It has been to the shop repeatedly and they cannot fix it! Please help.

Get all of the electrical connectors checked and cleaned with contact spray.

Your car has known wiring harness issues that cause all kinds of gremlins.
Do you know if it’s been replaced yet?

I don’t believe they have replaced them. Whenever I take it to the shop, they try to find the cause of the problem before they go and start throwing on new parts. Should I tell them to take a look at the harness next time I take it in?

Yes, it would be a good idea to mention it to your mechanic. Are you taking it to shop that specializes in Mercedes? The wiring harness issue is well known in '92-'95 models, and a knowledgeable indy or dealer should be aware of the problem. But you can probably confirm it for yourself by carefully slitting open a bit of the outer sheath and checking the condition of the wiring inside. During those years, MBz (and other European manufacturers) used wiring insulation that deteriorated, so you get shorting between wires inside the harness. If you have deterioration in your harness, it’ll be very obvious when you look at it. It may yet be a problem with the ASR circuit, but as benzman said, a bad harness causes all sorts of unpredictable symptoms.

Well I just got back the car from the shop after they had it for a couple days. They said that the throttle linkage assembly was seizing up pretty bad, and that once it got warm it freed itself. They replaced the cables/pins and polished/lubed all moving parts. However I don’t see how this has anything to do with why it would trigger the ASR light to come on. Though it might explain why the ASR light doesn’t come on when the car has had a chance to warm up. Maybe the throttle assembly frees up when the car gets warm, but when its cold there is something triggering the ASR. A seized throttle assembly may explain why the engine wouldn’t go above 500rpm when the ASR light is on (because for some people, the car is still drivable when the ASR light is on). So far the light has not come back on, though I’m still wondering how a seized throttle assembly would trigger the light.