Arthur,

Made a tester from the radio shack parts list, (came across your funny story about "Requesting Diagnostic Initiation")

Heres what It read

Pin 8:

Code 45 Fuel safety shut-off of electronic accelerator or cruise control active

Pin 11:

Code 5 Stop lamp switch (S9/1)
Code 11 Closed throttle recognition signal to engine control module (HFM-SFI or Left LH-SFI)

Do these codes mean anything to anyone? Ive been researching and yet to find any helpful info.

Ok I have an ovp relay on the way... I will post the results after I put it in.

I just put in a used OVP and have the same problems, took apart my OVP to see if there was any indicators of something damaged and there was nothing I can see visually that shows it is damaged in any way.

So I am now wondering what the codes I posted mean, and what I should try checking next.

I just put in a used OVP and have the same problems, took apart my OVP to see if there was any indicators of something damaged and there was nothing I can see visually that shows it is damaged in any way.

So I am now wondering what the codes I posted mean, and what I should try checking next.

See if you have a 1/4 " slack in the throttle cable at idle. Clear codes and see what re-appears.
Suspect is short in EA/CC harness. Pump the brake a few times before clearing codes.
Brake lamp switch is the one you want to check for return..

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A Dalton

I just went and checked the car,
I do have 1/4" slack in cable @ idle
I cleared the codes and none reappeared

I am going to run an errand and re check the pins and post results.

Although the old OVP relay looked fine, It seems easier to get the car to start after I replaced it. I can get the car to start 90% of the time right away by slightly giving some gas when cranking. If I dont give it gas when cranking, its 50 / 50 it will start.

Also I noticed that many other posters had a surging idle at all throttle levels, mine is only at idle and completely smooth with any amount of throttle, also if i put the car in gear at idle the surge dissapears....

Maybe this helps to narrow it down

Thanks all for reading and replying

Just ran some errands with the car, checked the pins again and all codes are gone EXCEPT code 5 on pin 14.... So does this mean a harness is bad? If so which should I check?

It indicates you have some sticking contacts on the brake switch...they wear out ....

I would change it.

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A Dalton

OK, will do, cheap part. Will this possibly change the idle?

Not sure..

The problem was the codes were coming up [45] as fuel shut-off. That comes from EA/CC module..which is why I mentioned cable setting and brake sw. Brake sw is not just for lamps, it also has contacts for CC and EA ..so, if they short , the ECU sees a contact to drop fuel. So, the brake sw is indicated by code, but it could be a misread by the DM for a harness short that feeds the EA actuator from the B/S..you have to get in there and take that apart to look at the wires in that short harness ,,but I would change the Brake sw first b/c they are a common fail part w/high milage and should be changed anyway, just like the OVP.

If you have a scope and a lot of diagnostic time , you could be sure ..but you don't , so I say change the BS before looking at harness and Actuator...that's the reasoning.
Don't ask if that is a complete/ correct diagnosis , cuz it's not..it is only a highly probable possibility with the info you have supplied.

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A Dalton

Arthur,


Thank you for the detailed breakdown, I will pick up a switch today or tommorow and post results. I want able to find the location of the brake switch, could you tell me where is?

Thanks

James

Archieves...

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A Dalton

Just put in new brake switch, no change. Also tested CC before and after replacement and it worked fine each time.

Tested for codes, had none on pin 8 and still had 5 and 11 on pin 14...
Cleared codes and started car and pumped brakes and no codes came back on pin 14

Drive the car for a few days, check again.

Jonathan

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Blue Ridge Mercedes
Jonathan Hodgman
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Enthusiast Service, Restoration & Tuning.
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