92' 400E 124 ABS light
 

I have a 1992 400E that has the ABS light on as soon you turn the key on.
The research I hve conducted in this forum has lead me to do the following.
1. I checked resistance on both wheel sensor leads under the hood and got 900 ohms on both sides.
2.I took of the wheel ends of the sensors and they were slightly dirty and wiped them off. They looked ok to me.
3.I checked the contiuity of the sensors. Was not sure if I did this correct.
I got some voltage on the drivers side while I turned the wheel.
4. I checked the blue fuse in the O.P.V., it was fine.
5. I found another double fuse holder near the fire wall. I put a new fuse in
the left side as it was missing.
Now I am not sure what to do. I have not seen anything that tells me anything except the small amount of voltage on the drivers side. My volt meter in ac reads 1k scale. Not very sensative? Is this the good sensor?

Chris

You have to test all the sensors, not just one..
,,and you don;t have an OVP on that chassis..

Thanks Arthur for the feed back. I test both front sensors and checked the ends for magnetic shavings. There was some black dust on the sensor itself and I observed 900 ohms on both front connectors, the female side. I have not located the back sensor wire yet. I found a different style connector square vs the round shape for the front. I will try reading and deleteing the codes and see waht I come up with.

Ohm reading only test the coil in the sensor for ohmc/comtinuity..A better test is to spin the wheel and see if the sensor puts out a voltage signal. The best test is a scope b/c you can see the actual ac wave pattern, but any kind of voltage reading is what you want to do for a diy sensor test.

Aurther thanks for your help.
I did another ac voltage test on the passenger side and got the wheel spinning very fast and saw some voltage. The drivers side gives a stonger signal. I was reading in Stu Ritters' 124 Bible that the sensor harness could also be an issue along with the sensor wire. Is that enough to determine that the passenger side is causing the light to be on and stay on KOEO and KOEO.

Chris

I is really hard to test a sensor without a scope pattern..it is an a/c signal and just having an output does not verify a good sensor.

You may want to see if there are some codes stored.

I made a code reader. There is a cable with numbered pins on the passenger(right) side near the upper strut mount. I am not sure of the pin count on the pins in the black box.

Chris

Oh, good
You mean a 38 pin connector??

If the tool you made has the bananna plugs , you will have to change the lead ends to a small wire to fit the 38 pin set-up.
The blk -will go to #1, the red + to #3 , and the odd to the module designation you are looking for codes on.

In this case I would send you to pin #6. This is ABS stuff.

go here and see page 12 for pin map. Than go to page 61 to get the correct hook-up and codes for your chassis [ which is a 124.034, by the way] That will be pin #6 access to ABS
Code retrieve tool procedure sequence is here in archieves [ or at site I send you to]

http://www.geocities.com/MotorCity/Downs/1039/mercedes/cs1000_mb.pdf

If that does not load , wait a few and try again..it is tempermental.
It will say Site Unavailable, but if you wait 30 secs. or so, it will load anyway....