Audi Wheel Speed Sensor Issues

Oscar Technician California Posted   Latest   Edited  
Updated
Braking
2006 Audi S4 4.2L 6-spd
MIL On

Hey everyone, 

We got this 2006 Audi S4 Cabriolet in the shop for transmission issues and ABS/Traction Control MIL's. The trans issues have been identified as low fluid from trans leaks. We are now concentrating on the ABS/Traction issue, we pulled code ‘00287’ for the right rear wheel speed sensor. We connected the Picoscope to both rear wheel speed sensors at the ABS control module, the waveform has been attached. The good sensor (left;red) fluctuates between +7.5v and -7.5v consistently at city speeds and higher, whereas the bad sensor (right;blue) is consistent but varies drastically from the left sensor where at points it fluctuates from +14v to -14v and as little as +.5v and -.5v. The initial thought was that something was affecting the tone ring, a bad wheel bearing or issues with the tone ring itself, etc. Inspection showed that everything was okay. Resistance/continuity was checked from the right rear speed sensor to the ABS controller and all checked okay. We were left at this point thinking either sensor or module. We opted to replace the sensor for obvious reasons and we were left with the exact same results as before. At this point we are thinking we may have a defective module. Has anyone come across this similar issue, is there something that is being overlooked?

Thanks in advance

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Mehmet Owner
Georgia
Mehmet
 

If left rear and right rear are interchangeable, swap them first. At least you would eliminate some things. Also I had an issue with a tire size, though it was the same size, it was a different brand, I got funky readings. Changed the tire and problem fixed.

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Noel Owner/Technician
New Jersey
Noel
 

Check for excessive play in right rear wheel bearing causing incorrect sensor to tone ring clearance.

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Louie Technician
New York
Louie
 

Hi I had a similar issue with a Porsche 996 it had a right rear abs speed sensor fault but it cleared when I replaced the right front lower control arm due to a worn ball joint​.​try correcting ANY loose suspension components first .BTW the abs light would only come on once a month but would happen more frequently as the ball joint got worse.

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Robert Owner/Technician
Rhode Island
Robert
 

Does the code set right when you clear it or do you have to drive it to set code. If it set no moving the check the wiring and controller, If you have to move then look at tone ring or wheel bearing

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Louie Technician
New York
Louie
 

The fault would set each time the car was driven about 3 miles when it was at its worst.

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Oscar Technician
California
Oscar Update
 

We found that the rear tires are of different brand but are the same size and have similar tread depth. One thing we did notice was that either the DTC would not clear at times or would come back immediately, without driving it. Oddly at times the code would clear and go several miles before it reset, but the signals always remained the same from start to end and before and after DTC set. We…

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