Gremlin in my E-320 finally diagnosed
 

Hey Guys,

Thanks for the advise about the ticking noise and fluctuating idle problems in my E-320 you've been giving me over the last few months.

I talked to my mechanic and told him I was taking my car to the dealership, since he couldn't figure out the problem without me throwing various expensive (like a new wiring harness!!) parts at it.

The dealership discovered that the cruise control/idle control thingy was bad. They simply threw parts at my car until the problem dissapeared.

The part new from the dealer is about $1400! I found one from Potomac German in MD for a bit over $300 and my mechanic will install it for free since I've had this problem for so long.

Anyone interested in a good wiring harness for around $200? I still have the old one that was replaced without needing it.

Was it the idle control valve that went bad Stefano? If I am not mistaken the records you got with the car indicated that the harness had been replaced. You may be able to sell it on ebay. Glad to hear you got it sorted out.

I think he's talking about the throttle actuator, aka EA / ISC / CC, Electronic Accelerator, Idle Speed Control, Cruise Control.

All three functions are combined in one part. If one function fails, then the whole part needs to be replaced.

It turned out to be the cruise control/idle speed control unit.

Part number: 1245455532.

My mechanic had told me he thought it was the wiring harness, which I bought independently and had him inistall it. 'Course that wasn't the problem! I'll try to sell the old one on ebay.

The mechanic at the dealership that diagnosed the actual problem said that the unit (brains?) looked as though it had been fried. They'd never seen that happen before.

Glad it fixed and I'm sure you are too!

A fried ECU is usually the by-product of a wiring harness failure.

If the replaced wiring harness on your 1995 with 190,000+ miles was the original, your mechanic did you a favor by having it replaced. It would be only a matter of time before it caused other serious issues. If it was the original wiring harness, you would be doing your fellow Benz owners a disservice by trying to sell it.

The original wiring harness was replaced, so this one was not the orginal. As it is, if I were to sell it and it turned out to be bad, I'd gladly refund the money.

That's what my mechanic said too, but I figured maybe he was just trying to make me feel less bad about having it replaced! :D