ABS light winks

[Daren]

Hi Eric and happy Thanksgiving,
For a few weeks, maybe even months, my ABS light comes on and goes off on occassion. Sometimes it will do this when I back out of my driveway and I feel/hear a growling sound and my brake pedal sinks a little deeper towards the floor. My 2002 Silverado, equipped with four-wheel disc brakes, still stops and when I shift into drive and pull away, the ABS light will go out within a block.

My truck has 186,000 miles and I have not experienced any ABS issues. The only brake work I have had to perform on this truck involved pads, rotors, and parking brake shoe replacement. This is just routine wear-out stuff. Back in the spring I did a four-wheel brake job and I even flushed out the old brake fluid in the process. It has worked well until this ABS light came on recently.

The first thing I plan to do is to check the ABS sensors to see if any wire is broken, if any connections and dirty and clean them, and plug in my ODB scanner that is also capable of checking ABS codes. I have yet to use this functionality of my OBD scanning tool.

My question is does this symptom sound like a defective ABS wheel sensor? The ABS light will come on and off while I am driving. Sometimes it stays on longer, but it always goes off and my truck brakes the same with the exception of what I described when backing out of my driveway sometimes.

It appears a wheel sensor is around $30 on Rock Auto, but as cheap as that sounds I still want to diagnose the problem before committing to purchasing any parts.

Am I even on the right track here? I haven’t had to mess around with ABS systems. They seem to be relatively trouble free. Maybe age and mileage has caught up with my Silverado.

Thanks for your input Eric,

Daren

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[Daren]

I take your advice to heart JTF. I will check the wiring and for a dirty/corroded connection/terminals.

I agree that replacing parts unnecessarily should be avoided.

I’ll find out more once I take it apart.

[Daren]

Okay, we had some mild weather here recently in Nebraska and I pulled the wheel/brakes and removed the sensor. It was a little grimy and I cleaned it up.

A few days prior I replaced the stop light switch since one of the codes indicated an issue with it.

After cleaning the sensor I plugged in and cleared the codes. I did have code CO281 which indicates a faulty stop light switch.

I drove it today and there were no issues. It will take a few more trips before I can deem it repaired, but it is starting to appear a $17 stop light switch was the culprit.

I think the worst scenario is I will have to replace the sensor I just cleaned.

Thanks for all the input everybody.

[Daren]

Well I got another ABS light event. I plugged in for the ABS code and got code CO227 indicating a bad wheel sensor. Nothing that can’t be fixed via $30 to Rock Auto.

Now I have another new set of problems. My Mother-in-laws’ ’01 Mazda MPV needs an alternator and I have discovered it is an act of congress to change.

[Author]

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