Jim Grant's Tech Tips
'99 Pontiac Grand AM, ABS Light After Brake Work
Q: The ABS light and Traction light in my '99 Pontiac Grand AM with a 2.4
L engine, will not extinguish even after I have changed my pads and
rotors. Any suggestions on how to get it to turn off or what to check
as to what might be the problem?
- Pablo S.
A: There is a funny thing about Anti-lock Braking Systems that many
people do not realize. The system doesn't know any thing about brakes.
That's right the ABS system doesn't know anything about brake pads,
shoes, calipers, rotors, brake drums, etc. In fact, I could remove
your brake pads, brake caliper, even brake rotors and drums on some
vehicles block the brake line so the fluid doesn't spill all out and
your vehicle's ABS system wouldn't even know they were missing.
Computers assume, yes they take for granted that the core components
of the braking system are in good working order. If you have an ABS
light on the first item that should be checked is the brake fluid
level. Many ABS systems do tie a fluid level sensor warning light in
the ABS warning light. But let's not assume and be sure the brake
fluid is at the correct level. You now know that you have good brakes
and that the ABS system doesn't know the difference. The next step
would be to have a code check performed on the ABS computer. With the
warning light being on there will be a code. That code will direct
you in which part of the ABS system needs diagnosis. It is also
likely that your traction control warning light will go out once the
ABS problem is corrected. The 2 systems rely on some of the same
sensors to operate correctly.