I have been informed by an independent shop, that I need a new "Idle Speed Actuator" for a 1994 E420 (85K mls). This is an expensive part (quoted $850 + labor); is it possible to get a used or rebuilt part?, without compromising the mechanical integrity of the car?. The shop also told me that this is a fairly common problem, due to exposed wires, that causes the burning of the actuator, and possibly also damaging the "Control Unit". To determine if the control unit is damaged (also an expensive part approx. $800), the actuator must be replaced first. Wouldn't this be a valid claim for MB?, this is due to defective wires, similar to the matter related to defective wiring harness, previously addressed in the forum. Please let me have your comments. Thank you.

Regards,

Hernan J.
1994 E420


[Edited by hescobar on 06-05-2001 at 03:54 PM]

Whoa, on that one. How did they come up with the conclusion that your idle speed actuator was burned out?

I had some serious performance problems with my 93 300E last year, and the service rep was quick to point out the same unit being at fault. Fortunately, they tried some other fixes before attempting to replace that part.

Replacing the actuator had NO effect on the problem, so they replaced it with the old unit. Finally, the car was back to normal with new plugs, a defective wiring harness, some plug wires and a temperature sensor. Still an expensive fix ($600, incl. labor), but not as substantial as having to pay for that actuator.

At least the dealer can switch out parts for diagnostic purposes, but I don't know if an independent shop can. Anyway, you don't have enough miles on that car for such a failure to occur.

Better shop around on that one...

Thank you for your information. I contacted the shop an requested a confirmation that the problem is the actuator; the shop confirmed the exposed wires short-circuited damaging the actuator; they offered to keep the old part to show me. The shop also mentioned that they repaired three other MB with the same problem, one of them had also the control unit (computer) damaged from the same problem. I hope I'm not getting ripped off. I really like my 94/E420 and have not had major problems, having plans to keep it and use it for some years to come.

Regards,

HJE
1994 E420

I am just a little surprised that MB would not have protected such an expensive unit a little better than that. How much would a little extra insulation cost?

Hopefully your control unit is fine. You are probably not getting ripped off, but I will attest to the $850 price, since that was the same that I got quoted from the dealer.