Ok so I have a very strange problem. My check engine light came on after starting the car. When I turn the car off, it still illuminates. It was on for all 8 hours I was at work. The car starts and runs fine. Also, the ASR dummy light was illuminated as well. I pulled the code for the check engine and it was code 17, some communication error. I tapped on the OVP in the engine compartment and it turned it off, and it seems to do it intermittently now. Do I have a bad OVP? BAd wiring? It sounds like a short somewhere.

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93 300D 2.5 Turbo, Black/Palomino 273K
09 E350 Black/Black 41K

My guess is you have some stuck contacts on your OVP, allowing closed circuit bypass...........They weld together as the contacts surface wears.
Common relay failure on high hours of service.

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A Dalton

When this happened to my car (94' E320), the infamous engine wiring harness was the culprit.

This car has a brand new wiring harness, along with EA harness.

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93 300D 2.5 Turbo, Black/Palomino 273K
09 E350 Black/Black 41K

Then I guess that the harness isn't the problem.

Why don't you remove the OVP (with the key off), and see if the light goes out?

..and while you have it out , check the part# on the side..if it is the old #, change it to the new type, regardless

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A Dalton

Ok will do. What is the old part number and what is the new?

I would have removed it yesterday when it happened, but it was a windy blizzard here and didnt want to be outside for too long.

Thanks for the advice guys...

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93 300D 2.5 Turbo, Black/Palomino 273K
09 E350 Black/Black 41K

Search faeture

New..000 540 67 45
Old.............. 52 45

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A Dalton

Thank you Arthur. I was just uncertain of the old number. I will check it out tonight.

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93 300D 2.5 Turbo, Black/Palomino 273K
09 E350 Black/Black 41K

I have a similar problem, the new number OVP relay and a new wiring harness, occasionally the engine controls will have power with the key off, I have narrowed it down to a sticky OVP relay (new one ordered).

I'm starting to have the opinion that havng a new one in the boot isn't bad insurance on these cars, and I'm betting that your OVP relay is the problem as those before me have said.

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Gone to the dark side

- Jeff

Yes ..it is a know fact that anything that goes wrong with the car can be, and has been , caused by the infamous OVP..[ except for dirty windshield]..

Actually , the main reason for OVP rearing its head on these chassis is , unlike the earlier models that would work manually, is the HFM/SFI cars are FULL Electronic and all power has to go thru the OVP with no backup. So a poor connection or diode on an OVP on these late chassis is chaotic....
Ealier chassis will actually still run and start even if you pull the OVP, but these will do neither if you take the OVP out....

Plus , if you have one in the trunk, Murphy will take that into consideration and you will never have an OVP problem again simply b/c you are prepared, and almost hoping , for OVP mal-function....

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A Dalton

Update: I installed the new OVP relay today and bingo, all problems solved.

What was interesting is that the old one did have the "new" part number. 000 540 67 45

Thanks for all your help guys. Im glad this one was a cheap fix, for the most part.

p.s. I took the old one apart, and it was all corroded in the lower half.

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93 300D 2.5 Turbo, Black/Palomino 273K
09 E350 Black/Black 41K