MB Code 107 Need Some Help

[jnenad16]

This question is for my fellow techies such as slammed_c, manny or benzaddict. I got a 1995 C280 at my shop that keeps dying after it starts. This is second time it came to me for the same problem.First time I scanned it, I came up with mb code:
110 - Voltage to HFM control unit , incorrect.
So I checked the alternator and it was charging around 18V(I know). I replaced it and it seemed to have fixed the problem.
five days later(today), the customer came back with the same problem. I scanned it and and came up with the mb codes:
107 - Ignition dwell angle control output stage, short to ground.
110
I checked the alternator again it was fine(14V). My quess is that this time its either crank position sensor or the cam position sensor. The reason I'm asking you guys this question is because this is the first time I ran into this code.
Any tip would be highly appreciated as this car needs to be done by tommorow morning.

Thank you,
Nenad

[stox]

Could be the dreaded wiring harness. Has it been replaced in the lifetime of the car?

[jnenad16]

the harness hasnt been changed, but I dont think that could be the problem since only 1993-1994 benzes had wiring harnesses made with defective wires. plus the harness wires are not brittle, they are still flexibile.

nenad

[benzaddict]

jnenad, check the overvoltage protection relay. If it says "made in Austria" or "Hungary" then it's most likely the issue. We replaced a ton of these under warranty for intermittent stalling and no start problems, there was a DTB about it years ago. You get DTC code 107 stored and extreme voltage output, just like you described. The good relays say "made in Germany" and are all that is available anymore. This is a very common problem on '94-95 w202 and '93-95 w124.

If your overvoltage relay checks out ok, I would put a scope on the crank sensor and see if it goes open circuit when it gets hot. Usually the crank sensor won't store a code though. Good luck.

[manny]

Nothing for me to add.
I think benzaddict said it very well. ;)

[jnenad16]

benzaddict, thanx alot for your help. I just figured that, too. I suspected it was the problem the first time it came in, but I went with the alternator first and it seemed to be the remedy, for a few days. but now I swapped the OVP relay and the car has been running with no problems. Once again, thank you all for your help.

Nenad

ps the faulty one was made in germany and I replaced it with the new one thats made in hungary. hope it lasts.

[SLAMMED_C]

well ya all beat me to it.
good work benzaddict.. you know your stuff man..
and yeh the crank sensor wont store a code.. you need the car conected to a computer so you can read for codes as your cranking.. the only way to see a bad crank sensor with the computer... as its doing it.

[marksbenz]

Wheres the overvoltage relay located at? Because sometimes when the car is hot it dies right after i start the car.

[jnenad16]

Originally posted by marksbenz
Wheres the overvoltage relay located at? Because sometimes when the car is hot it dies right after i start the car.
its located in the computer bay. its the long silver relay with a fuse on top and a clear plastic cover.

nenad

[RacerXofFL]

Beat me to it too, fixed mine as well, I used to get the dwell to 0 error, and stall like 30 seconds after start, did it in the bay 7 times in a row, it was austrian overload protection relay