LMM: ABS and Emergency Brake Light come on

[bow-tielover]

So recently after going from 35" tires to 37" tires (don't know if this has anything to do with it) my ABS and e-brake will both come on while driving. The dash will chime for about 10 seconds and then stop but the lights don't go away until I turn the truck off then re-start it. No check engine light comes on, just those. It mainly does it when accelerating on to a freeway.

Anyone have any idea what's going on here?

[Jaybeecon]

Mine started doing that after I changed wheels. Turned out that the new wheels were rubbing against the wire for the front wheel ABS sensors - this caused the warning chime and sometimes ABS light for a few seconds, usually when making a tight turn.

I didn't figure all this out until after the wire got totally cut on one side and took out the ABS computer.

Take a quick look along the top of each A-arm. It's a single black wire that should be clipped in to the top of the A-arm. If the wire is abraded, then it's getting rubbed by the wheel or tire.

[heymccall]

You need the truck programmed (specifically the EBCM) for the larger tires. I explained why it does that, here HELP! Ever hear of this???

But, I don't know the solution. Now, in that post, I referenced changing gear ratios, which is essentially the same as going with larger tires.

[bow-tielover]

Originally Posted by heymccall

You need the truck programmed (specifically the EBCM) for the larger tires. I explained why it does that, here HELP! Ever hear of this???

But, I don't know the solution. Now, in that post, I referenced changing gear ratios, which is essentially the same as going with larger tires.

Thanks. I read else where that it's because I re calibrated for 37s and that if I set it back to 35 it should stop. I'll try that and check the sensor wire too and see how that works out.

[heymccall]

If it's a sensor wire, it would turn the ABS lamp on at startup. And, whomever said a shorted WSS took out the EBCM, took you for a ride.

[Jaybeecon]

Originally Posted by heymccall

If it's a sensor wire, it would turn the ABS lamp on at startup. And, whomever said a shorted WSS took out the EBCM, took you for a ride.

I am not going to dump the mechanics & tire supplier who have given me years of excellent and honest service. Perhaps it was coincidence, or perhaps you are mistaken but the facts of my particular ABS are very definite. The short version:

1. Intermittent ABS light. Leads to 100% ABS failure
2. RS front ABS sensor wire broken. Hub and ABS sensor assy replaced. ABS still out. Mech finds that EBCM not processing signal
3. EBCM replaced, ABS has been fine ever since.

[Sprj8008]

The other thing that will cause both those lights is low brake fluid.

[bow-tielover]

Originally Posted by Sprj8008

The other thing that will cause both those lights is low brake fluid.

That's good to know!

I re-calibrated my tire size down to 36 and re-zip tied the wires and the problem has seemed to go away.

[bow-tielover]

Update:

Problem gone. Must have been one of the two.

[PrivatePilot]

Thread moved to drivetrain forum.