2002 GMC Sonoma abs

2002 GMC SONOMA
87,000 MILES • 6 CYL • 4WD • AUTOMATIC
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DMOORE60
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abs + brake trouble lamps come on at same time. Usually when starting, after lamp test the 2 lights come back on until the nest start cycle.

dealer read NO code but determined the control valve oump had a fault. I later found out that this would have produced a fault! The valve ($800) was replaced but the same condition still exists.

What wpuld cause the false triggering of these 2 lamps?
Dec 3, 2009 at 9:02 AM
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SERPENTRACER
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the wheel sensors can trigger the light.
the "parking" brake light will illuminate when there is a brake system problem believe it or not.
it can also indicate low fluid in the reservoir too.

when you turn the key on the system does a diagnostic check of the circuit. when it detects a fault the abs light in the dash will illuminate.
I'm not sure exactly how it knows if the rear wheels lock..I've been told it knows this using the speed sensor located in the transmission. (bolted to the side of it)

on the 2 wheel drive trucks the front sensors are easy to remove but since you have the 4X4 you would have to buy the hub since the sensors are built into it. and they are $$$.
the sensors can be tested with a multi meter at the plug. search the net..that's where I found this out. I tested mine and they were both dead.
I sprayed brake cleaner on mine and they both quit working.

both of my lights were on on mine. I got mine from a junk yard for less than $30.
the connectors are tough to access though.
Dec 19, 2009 at 6:31 PM