Last week, my 1987 260E would not hold an idle. It would stall at most stoplights. The Antilock light on the dash was illuminated. Sometimes the SRS light would come on as well.

I made an appointment at my local independant MB shop, and on the way there, the antilock light on the dash went out, and the idle came back to around 900 rpm, and no stalls.

This has since happened 2 more times. I finally got it to the shop when the symptoms were present. The shop replaced the belt tensioner and adjusted fuel mixture and cleaned the throttle body.

I picked it up from the shop today, the idle is low, about 500rpms, but it does not stall. The ABS light is still illuminated, I am 450 dollars poorer and the car is still not right.

Can someone on this board enlighten me on what this gremlin could be? I do not have a good wiring diagram, can someone tell me what illuminates the ABS? I think if I trace that circuit, I will find the root cause to this issue.

Thank you.
Mills Stansberry
Greenville SC

Most likely it is the overvoltage relay (OVP). Check the fuse on the OVP. It is located behind the battery, by the firewall. It is a small metal box with a red "american style" fuse on top. If you are lucky, it is only the fuse. If it is not, you have to buy the OVP. Do a search!

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J.H.
'86 300E

OVP without a doubt take it out and shake it - if it rattles it's shot.

It's very unlikely to be anything but the OVP, replace it.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

I agree with everyone else.

The troubles you described is EXACTLY what I went through about a year ago. I got a new OVP and that solved everything. I think I paid $50 for mine, but I believe this site sells them for $15-35 can't remember. It's an easy DIY...takes no more than 1 min to fix.

GL

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JR
1986 Gold 300E 4Dr automatic

Wanted to feedback to the forum that the OVP relay was the correct diagnosis. I Replaced it and the idle returned to normal and the ABS light went out. My mechanic refunded the $450 and put the original belt tensioner equipment back on. So my problem was solved with a $65 relay.

Thanks to the forum for the help.

Mills

Idle is 900RPM? If so, I don't beleive that is normal.

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2008 E350 4matic / Black/Anthracite

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Gone but not Forgotten:
2001 E430 4matic, 206,xxx miles, Black/Charcoal
1995 E320, 252,xxx miles, Black/Grey
1989 260E, 223,00 miles, Black/Black

The symptoms are very common for the OVP. A good experienced MB mechanic would have found the problem BEFORE changing all those parts...unless, he is looking for a quick buck. Good thing he refunded the money. Either way, I would look for another MB mechanic.
Good luck!

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J.H.
'86 300E

Our TE4Matic was experiencing exactly the same problems: ABS light on; poor starting, and a weak idle. My wife went to the local MBZ dealer with the information from this thread, but they said it couldn't be the OVP relay. Well, I brought the car to my favorite independent, and, sure enough, he replaced the OVP and bingo: ABS light off, correct idle and easy starting! What you fellows know puts the dealer to shame! I'm sure the dealer wanted to replace the entire ABS system first.

I want to especially thank my friends: J. Hidalgo, billabong123, Peter and jrmd01. You guys are the greatest! Thank you.

Regards,
Bob

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'94 E500 Anthracite
'92 300E 4Matic (donated to charity)
'90 300TE 4Matic

Thanks for the help guys...I came across this thread and it saved me allot of trouble. My car had been running like that for a week, never stalling, but idling around 500...and the idle would increase when i pumped the brakes, I figured it had to be something electrical. But since I found this thread, I didn't even have to get a diagnostic. you guys rock!

I have a 1991 Merc 260E Auto with an ABS warning light proble. I note the comments about the relay but i cant locate the item on my car. Can any one help please.

I assume Wales as in the British Isles. This means that all your important relays and computers are behind your battery. There is a plastic cover to be removed. In my 260e there is another small plastic cover over the OVP see fotos. See foto of FPR and OVP relay. You may have the newer type of OVP which has a red top and two fuses. Get the latest variant of the relay to suit your car. M.B. added variations to these relays over the lifetime of using them. This was always a problematic part

Found it !!!!! Now to test it. In the event that this is not the problem any ideas where else to look...

Many thanks

The only real way to test is to try another in the car.

There is a zener diode in the relay. It goes out of electrical spec.

Result...!!!! Changed the OVP and all is well. For good measure i also fitted new discs, pads and a few other parts but all is now well....many thanks for your advise and help...

Philip