W124 rough idle and ABS light on
 

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

Did you jump start your car recently?
 

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! ;)

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

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

problem solved
 

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.

I would look for another MB mechanic...
 

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!

You Guys Are the Greatest (and thanks to this Forum, too!)
 

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

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!

Dead on
 

Wow, My 300e began to run rough and the anti lock light came on. I did an archive search for "antilock idle" and bam. Found this thread, got the OVP relay locally within 12 hours, and I back on the road. I love this site!

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Ovp
 

Where is the OVP relay located on an 87 300D?

On my vehicle, it's located along the firewall area, about mid-way across.

Here's a photo of one for an 87 300D obtained from this sites FASTLANE parts area:

http://catalog.eautopartscatalog.com/mercedesshop/sophio/wizard.jsp?partner=mercedesshop&clientid=catalog.mercedesshop&baseurl=http://catalog.peachparts.com/&cookieid=1EQ0PTV2S1JU0RT2WW&year=1987&make=MB&model=300-DT-002&category=P&part=Overload+Relay

Merc 260E Auto
 

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.:mad: