ABS light comes on?

1997 GMC SIERRA
249,000 MILES • 5.7L • V8 • 4WD • AUTOMATIC
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JIGBIM
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1. Scan fails.
2. ABS light comes on transmission gets out of sync.
3. Pin 5 in dlc is signal ground, but with key on I read .04 volts could this cause scanner not to link with ecm . My understanding there should be no voltage on pin 4 or pin 5 when grounded used dvm to test.
Jul 1, 2024 at 7:19 PM
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STRAILER
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Pin 5 is ground so it should never show voltage, but .04 is close to nothing but I would check or replace the ground circuit to be sure you are getting a good connection, here is the wiring diagrams for the ALDL connector so you can see how the system works. I would also check the fuse # 7 in the use panel inside the truck. Check out the images (below). Please let us know what happens.
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Jul 2, 2024 at 10:03 AM