I'm going to check on this:
ABS Light On, DTCs C0265, C0201, U1041 Set and/or Loss of Communication with Brake Module (Reground EBCM Ground) #04-05-25-002A - (Apr 22, 2004)
2004 Buick Rainier
2002-2004 Cadillac Escalade, Escalade EXT
2003-2004 Cadillac Escalade ESV
1999-2004 Chevrolet Silverado
2000-2004 Chevrolet Suburban, Tahoe
2002-2004 Chevrolet Avalanche, TrailBlazer, TrailBlazer EXT
2003-2004 Chevolet SSR
1999-2004 GMC Sierra
2000-2004 GMC Yukon, Yukon Denali, Yukon XL
2002-2004 GMC Envoy, Envoy XL, Sierra Denali
2004 GMC Envoy XUV
2002-2004 Oldsmobile Bravada
This bulletin is being revised to update the Ground information. Please discard Corporate Bulletin Number 04-05-25-002 (Section 05 -- Brakes).
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 replacements 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
DO NOT REPLACE THE BRAKE MODULE.
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. Clean the area, front and back, using a Whiz Wheel?.
3. Install the bolt, ground and a star washer to the frame.
4. Install a star washer and nut to the backside of the frame.
Tighten
Tighten the nut to 9 N?m (79 lb in).
5. Cover the front and back side of the repair area using Rubberized Undercoating.