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Discussion Starter #1
I apologize up front if this is covered in a post I didn't find with the search engine?

I have recently aquired a 1991 300SL, w/out limited slip but with ASR. Trouble shooting the ABS right now as the light comes on and the top won't work. I have learned that there are two rear speed sensors in the diff. carrier, both reading good (it's looking more and more like my problem is a bad ABS / ASR control module). Anyway, aprat from that, while looking things over I also saw the rear brake sensors and then these two lever action sensors on either side of the back of the rear axle? What are those for? The car doesn't have self leveling.
 

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scan the car for codes, otherwise you ll be shooting in the dark...
 

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Discussion Starter #4
scan the car for codes, otherwise you ll be shooting in the dark...
Thank you for the advise but that is where I started:). That's how I know it's a bad ABS CM. Just wish decent OBDI scanners weren't so pricy! Had to use the jumper switch / read codes at top switch methodology for most of the diagnostics.

Thanks for the ID on the roll over switches, makes perfect sense once I read the words.:eek:
 

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Still, I would invest 100 dollars in a pro shop reading for scan with a real STAR scanner, to make sure before spending any money on parts...
 

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Greek God of the R129
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The first thing I would do is to CK the fuses, front and rear.

The other, I would remove the front wheel ABS sensors, clean and remove metal fillings, etc, specially the left one, this is the one that sends the signal......

Regards,
aam.
 

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Discussion Starter #7
Gentelmen,

Thank you for all of the advise on the ABS problem, I was really just looking for an answer to the roll over sensors. For what is it worth the ABS has been diagnosed as follows:

1. Light on as soon as car rolls ten feet, clears at each startup. Code in RST module prevents operation of otherwise working RST function.

2. All four ABS sensors checked for continuity, resistance and resposne to rotation, all good.

3. All codes scanned by MB dealer and diagnosed as bad ABS control module.

While it is ofen a simple fix (sensor, etc.), this one just ain't. Again thanks for all the advise on the ABS but got it under control.
 

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Good luck...
 

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Greek God of the R129
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Gentelmen,

Thank you for all of the advise on the ABS problem, I was really just looking for an answer to the roll over sensors. For what is it worth the ABS has been diagnosed as follows:

1. Light on as soon as car rolls ten feet, clears at each startup. Code in RST module prevents operation of otherwise working RST function.

2. All four ABS sensors checked for continuity, resistance and resposne to rotation, all good.

3. All codes scanned by MB dealer and diagnosed as bad ABS control module.

While it is often a simple fix (sensor, etc.), this one just ain't.
Again thanks for all the advise on the ABS


( but got it under control. )

This doesn't help the forum.
Please explain what you did?

Regards,
aam.
 

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Discussion Starter #10
This doesn't help the forum.
Please explain what you did?

Regards,
aam.
aam,

Not sure what you are saying? I'm not trying to be offensive or abrasive but this thread was NEVER about my ABS issues; it was, and is about my wanting to know what some other sensors were, which was answered.

I wasn't aware I was required to re-hash the ABS issue, which I have another thread on, in this thread just because someone volunteered off topic advise? Is playing along with thread hijacking a forum requirment?

Besides, I cleaned and checked all four sensors, confirmed continuity and correct readings with wheel spin and then took it to a MB dealer whose read all codes and told me my ABS module is smoked, AS STATED ABOVE. What do you mean by what did I do?
 

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Greek God of the R129
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Sorry for been late, my modem just passed away. :(

See most threads are getting out of subject, so to get a strait answer is almost imposable.

As a matter of fact, I am one of the first to stray. Haha.

You have my apologies, I didn't mean anything bad.....

I was just stating, that when we post, it is nice for the members to do a follow up, that will help the next guy with the same problem.

So the answer/problem was that the ABS module went south.

I thank you.

Regards,
aam.
 

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Discussion Starter #12
aam,

No harm, no foul. Besides I probably overreacted and I may have to eat some crow:( I got a replacement ABS / ASR control module and still get an ABS light as soon as I roll ten feet so back to the drawing board! In addition my top is confused as heck! Closes from the down position fine but wants to simply lock down again when I try to raise it. :surrender: Back to the stealership oin Monday for a total rest of everything and see what codes remain! Verrrry frustrating. I'll be spending the rest of tyhe weekend carefully reading all ABS rerlated stickys and posts.

Zachmac
 
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