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Old 09-07-2004, 06:16 AM   #9
GMMerlin
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Re: Re: Re: ABS Activating Un-necessarily

Quote:
Originally Posted by FCFFUZZYFACE
Don't rely only on the resistance measurement. GM has instructed me that we can fail a sensor by resistance measurements but we cannot pass a sensor by resistance measurements. I've had many bad sensors check in spec by the ohm meter. A scanner with a live wheel speed readout is the most reliable and quickest way to find the problem. Typically you will find one sensor that does not start reading wheel speed as soon as the other sensors I.E. three sensors will show 5mph and one will show 3mph (weak sensor). If the wheel speed is ok then check the toothed ring to see if it has a crack. Have fought this problem many times and there will be no trouble codes set and resistance will be in spec.

FCFFUZZYFACE
This is true, but the original poster does not have a scanner to perform the diagnosis.
If the resistance check is within specs, next you can check the AC voltage output of the sensor..this will show if a sensor is dropping out at low speeds. Since the sensor sends an AC signal to the EBCM, you will be reading the same input that the EBCM does and will not need a scanner to read the signal.
Once it is determined which sensor is giving the problem, then you can check for cracked reluctor rings.
One diagnostic step at a time.....
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