ABS and Brake light randomly come on.

[tanz45]

Even with a retune for the gears, some trucks still will throw the occasional ABS/Brake light. Mine did it, and others on GMFS will say the same.

[chvy=power]

yea mine started doing the same thing after i swapped gears...it an abs code just plug a scan tool up to it and read wat code it is... mine said wheel speed mismatch or something like that

[Jimmy_d]

ok thanks guys.

[country_3030]

There is a TSB for this. It has you clean a body ground.


Condition

Some customers may comment that the ABS light is on. Upon further inspection, DTCs C0265 and C0201 may be set in the brake module. It is also possible for DTC U1041 to set in other modules. There may also be a loss of communication with the brake module.

Cause

A poor connection at the EBCM ground is causing unnecessary replacement of brake modules.
Important:
The EBCM ground is different for each application. Refer to the list below for the proper ground reference:

^ Midsize Utilities = Ground 304

^ SSR = Ground 400

^ Fullsize Trucks and Utilities = Ground 110

Correction
Important:
Do not replace the brake module to correct this condition. Perform the following repair before further diagnosis of the EBCM.

Perform the following steps to improve the connection of the EBCM Ground:

1. Remove the EBCM Ground. The EBCM Ground is located on the frame beneath the driver's side door. If multiple grounds are found in this location, the EBCM ground can be identified as the heavy (12-gauge) wire.

2. If the original fastener has a welded on nut, remove the nut from the frame, and if required, enlarge the bolt hole to accommodate the new bolt and nut.

3. Clean the area, front and back, using a tool such as a *3M(TM) Scotch-Brite Roloc disc or equivalent.

4. Install the ground, then the washer and then the bolt to the frame.
Important:
It is important to use the bolts, washers and nuts specified in this bulletin. These parts have been identified due to their conductive finish.

5. Install a washer and nut to the back side of the frame.

Tighten

Tighten the nut to 9 Nm (79 lb in).

6. Cover the front and back side of the repair area using Rubberized Undercoating.