A Few months ago I replaced my unit bearings I did the LF first and had no Problems a week later I did my RF unit bearing and ever since I have had My ABS light on A/E has a DTC C1145 speed sensor RF input circuit failure. I have tried pluging in my old speed sensors from the old unit bearings and i still get the same Any suggestions on where I start to diagnose this problem

 

Do you have an analog or digital volt-ohm meter? Put it on the lowest AC voltage setting and place the leads on the terminals of the sensor wire. I have used paper clips to access the terminals. You should see a rise and fall in voltage generated by the sensor when the wheel is raised and spun rapidly. This would indicate the sensor and exciter ring are ok. Check for resistance across the chassis end of the sensor wiring connector for an open or ground.

 

Thanks I did exactly that. the new sensor was no good I also checked for resistance on the new sensor and it was at 0. where as the old one gave me a reading.

 

yep willing to bet the sensor is bad out of the package......

 

Yup it was I thought I might of broken a wire when i unpluged it Glad I thought to keep the old ones

 

Great test tip Roland. Reps to you.

 

Thanks Robin. I use this test method all the time at work. The exciter rings get dirty and the sensors get out of adjustment on our company OTR trucks & trailers and dump trucks. Once I read codes to determine which wheel it is and fix it, I recheck it with the meter to verify it's all good again.

 

Is there a way to clean the rings and adjust the sensor? Or, is it just an R&R job. The sensor assemby is pretty pricey for the left and right front sides.

Thanks