Help Please - ABS-ASR - W126 Sec 560

[tobyio]

Hi,

Here are my symptoms would anyone know if this is likely to be all be connected to the same fault?

My 1990 560 Sec ABS light does not go out at all, my ASR light only comes on when engaging reverse, once i put it back in drive the ASR light goes out.

I wanted to see if the back wheels both spun, first go only the offside wheel span, second time only the nearside span and then third and forth time they both span.

The accelerator pedal does not feel responsive, the first 40% of depression nothing happens the car only moves after about 40% depression.

Any help is appreciated, thanks

 

[grober]

Circuitry is likely to be similar to this
http://www.autolib.diakom.ru/CAR/Mercedes-Benz/1995/E320/SYSTEM WIRING DIAGRAMS/5409.pdf

The cheap things to go wrong are wheel speed sensors, the brake pedal switch and various earths in the system. Then its the electronic control units with their big connectors [ worth checking for corrosion on the pins]and finally the biggy the ABS /ASR HYDRAULIC UNIT- there are a couple of relays inside which can go wrong but getting replacements can be tricky.

 

[tobyio]

Thanks Grober

 

[grober]

This is a good article- on the ABS unit itself- worth reading the comments at the end also.
Mercedes-Benz W124 ABS Relay and Pump Replacement | 1986-1995 E-Class | Pelican Parts DIY Maintenance Article

 

[tobyio]

Thanks again! i will take a look tomorrow hopefully!

 

[tobyio]

I took a look today, but my abs unit is different to the one in the photo. I have a 500 sec and 560 sec and the one in the photo above is from a 500, my 560 has different relays on it as well so couldnt swap them to try.. sigh.

 

[grober]

The other easy thing to check is the OVP relay which supplies power to various units ---Engine ECU, Fast idle motorised valve and the ABS System. Low voltage will trigger an ABS fault.
Here's Ken's tips on older ABS system sensors

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[grober]

In terms of your ABS hydraulic unit internal relays if any are faulty it may be possible to repair them provided you can take the "can" off. Usually they are pretty simple inside with only a few components mounted on a small circuit board. These can develop " dry joints" where they are soldered on to the circuit board tracks. Sometimes all that's required is to run a soldering bolt over the joints to reconnect them properly to restore function
here's a how to video

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[tobyio]

thanks, great videos

 

[abs206]

thanks, great videos

Tobyio what was the fix to your ASR hard pedal on your sec?

Thanks