Front Wheel Speed Sensor

[dbmoylan]

Would anyone happen to know if a front wheel speed sensor was failing on a W140, what symptoms would one observe? Thanks.

 

[television]

no ABS, or ESP if fitted, no CC, and no navigation on an APS 30 if fitted, plus a few more

 

[dbmoylan]

Thanks again Malcolm. Am testing the reboot of the ECU and did not want this sensor to affect its relearning. I read on my Baum VScan tester the front left sensor registering 9.6Km/hr when the car was stationary. Figured the sensor is on its way out.

 

[jibcl500]

Might be worth removing it and checking for iron filings, mine registered faulty after I had reconditioned the front brakes and the end of the sensor was chocka with metal filings, cleaned them and all ok, DONT tap them they can be easily damaged.

jib

 

[r129co]

I have these if you need one
Carl

 

[type49]

A failed/failing sensor can "sometimes" be detected by driving car slowly & braking gently. You may feel the ABS pumping the brake pedal when there is no reason for it to be activating at all. Also, this system goes through a self test when first starting a journey. Start up & drive off slowly, you should hear the ABS pump activate for a second. If the ABS warning light comes on after this, it's usually a sign of a failed wheel sensor - but not always!!

 

[wireman]

The self test occurs every time the car speeds up from standstill thru about 3 MPH, the ABS detection system cuts out as the car slows below this speed as well, if it didnt the ABS would keep interfering when you maneuver the car at slow speeds. If the ABS is in operation the low speed cut out does not occur untill the car stops.

Type49 & JIBCL have it with the sensor details,
lamp on after you move off = sensor/wiring fault,
lamp on from go or just at random OVP relay/wiring.