LLY: ABS light on

[quinton]

Have a truck with just the ABS light on, no parking brake light. Throws codes for all wheel speed sensors. (pic posted) I’ve checked the two grounds, on frame and cleaned them, checked fuses, checked for broke wires, last thing haven’t swapped is the ABS computer. Was just trying to see if there is anything else I might look for before spending the money on one. I’ve done research and everything I’ve read they have both lights on. (parking brake and ABS light)

 

[dndj]

The EBCM (ABS) module has a tire size calibration value programmed in. From what I've read in an old thread from Ben, this is just a calibration value for the wheel speed sensors, doesn't affect the speedometer at all. It's configurable with a Tech2. Since you have all 3 codes (FL, FR, Rear speed sensors), I would check the tire size value of this first before replacing the EBCM.

If it's verified to be set to the correct tire size, then yeah if it was my truck I would replace the EBCM next.

 

[quinton]

The EBCM (ABS) module has a tire size calibration value programmed in. From what I've read in an old thread from Ben, this is just a calibration value for the wheel speed sensors, doesn't affect the speedometer at all. It's configurable with a Tech2. Since you have all 3 codes (FL, FR, Rear speed sensors), I would check the tire size value of this first before replacing the EBCM.

If it's verified to be set to the correct tire size, then yeah if it was my truck I would replace the EBCM next.

Do you have the link to that thread? I’ve adjusted tire size in tune, never had a issue like this before with tire size except on lmm+ and those would throw abs and park brake light. Never seen/heard of the abs module needing calibrated, but haven’t looked into them that much.

 

[gmduramax]

What size tires are on it?

 

[dndj]

Do you have the link to that thread? I’ve adjusted tire size in tune, never had a issue like this before with tire size except on lmm+ and those would throw abs and park brake light. Never seen/heard of the abs module needing calibrated, but haven’t looked into them that much.

The thread is on the "other" diesel forum, not sure if it's cool to post a link? EDIT: James says OK. https://www.dieselplace.com/threads/tire-recalibration-w-tech-2.79016/ See the 4th post from "DURAtotheMAX"

Also the factory service manual specifies tire size must be configured in the EBCM after replacement.

I can go shoot a picture of that screen on my Tech2 if it helps, although I've never used the function myself.

 

[Chevy1925]

You can post it, won’t hurt anything. Just adds info.

I don’t think it’s his issue but it’s worth a try.

 

[quinton]

What size tires are on it?

They are 33’s. Never had a issue until going bigger than 35’s and that’s on lmm’s. I don’t think tire size is the problem. I’ve tuned lb7’s and Lly’s with 37’s no issue.

 

[JoshH]

A tire size calibration won't throw a circuit code. If you have verified the wiring is good, it is probably the ABS module. I've had to replace a few of them.

 

[quinton]

A tire size calibration won't throw a circuit code. If you have verified the wiring is good, it is probably the ABS module. I've had to replace a few of them.

That’s what I’m leaning toward. I just wasn’t sure if there was any other part of the system I might have missed on checking.