| Subject: | ABS Light On DTC C0055 C0235 C0236 or C0237 Stored In The EBCM |
| Models: | 1998-2008 All Chevrolet, GMC, Buick and Oldsmobile Mid-Sized Trucks and Utilities |
| 1998-2008 All Chevrolet, GMC and Cadillac Full Sized Trucks, Utilities, and Vans |
| 1998-2005 Chevrolet Astro |
This PI was superseded to update model years. Please discard PIT3521D.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
ABS light on speedometer may be erratic. DTC C0055 C0235 C0236 or C0237 stored in the EBCM. This concern may be intermittent and not easily reproduced.
Recommendation/Instructions:
Using the Tech 2, check the EBCM, ECM/ PCM and/or TCM for any speed sensor related DTCs. These DTCs will need to be diagnosed first. Follow published diagnostics for related DTCs, repair and evaluate the vehicle after repairs are complete. If no DTCs exist
in any other module, inspect the rear VSS sensor circuit(s) from the rear VSS sensor to the related module (ECM, PCM or TCM) for integrity. These circuits are 821 and 822 or 400 and 401 depending on model and model year (use SI to locate the schematic that applies
to your application). Repair or restring these two circuits as needed. Evaluate the vehicle.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
