ABS light comes on?

1997 GMC SIERRA
249,000 MILES • 5.7L • V8 • 4WD • AUTOMATIC
Avatar
JIGBIM
  • MEMBER
  • 1 POST
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 12:19 PM
Advertisement
Avatar
STRAILER
  • ✓Experienced Mechanic
  • 55,238 POSTS
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.
Image (Click to enlarge)
Professional Diagram for 2CarPros Members
Click here to log in and view diagram.
Jul 2, 2024 at 3:03 AM
Join 2CarPros for free, one of the most advanced car repair communities on the internet. From first-time drivers to seasoned mechanics, everyone is welcome to reply, share details, and get better answers. You can add a temporary image or video first; uploads are limited to 20 MB.
Ask a Free Question
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.