amgmercedes

My 93 E420 has the following indicated faults which I found out using the diagnostic LED:


6 blinks: idle speed control inoperative.
Is there a part I should replace here? My idle sometimes fluctuates slightly, but most of the time its fine.

25 blinks: Knock sensor
Where is the knock sensor located? How do I know if I should already replace it?

26 blinks: upshift delay switch over valve (SOV) open/shorted
What does this mean?

Thanks.

Jer

There are very detailed test programs to go through when looking for the cause of a fault. It could be anything from a damaged wire to a malfunctioning component. One of the few ways to check is to use the socket box and a multimeter. However, socket boxes and the associated cables are usually too expensive for a DIY to justify purchasing. Still I can send you pages from the service literature on how to pin-point the faults.

amgmercedes

Uh oh, sounds complicated.

Jer

In this case you might be better off taking the car to the stealer or an indie MB mechanic. Tell him you found those faults and ask him to hook up the socket box to find out what's causing them.