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For 1990-2009 cars only

Service Brakes Soon Message DTC C0299 - keywords 00 5a ABS booster EBCM lamp leak light message vacuum

Subject:Service Brakes Soon Message DTC C0299

Models:2007-2008 Cadillac Escalade, Escalade ESV, Escalade EXT
2007-2008 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2007-2008 GMC Sierra, Yukon, Yukon XL, Yukon Denali, Yukon Denali XL



This PI was superceded to change the recommendation. Please discard PIT4046C.


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:

Some customers may experience a "Service Brakes Soon" message on the Drivers Information Center (DIC). After initial inspection, you may find a current or history code C0299. Diagnostic code C0299 can result from two issues. The first may be an electrical concern with the Active Brake Booster solenoid or related wiring. The second may be low vacuum detected in the brake booster.

Recommendation/Instructions:

*******The following is for 2007 MODEL YEAR ONLY.*********

Please use the following for assistance in diagnosing the cause:

If the DTC C0299 sets immediately after cycling the key, the concern is most likely an electrical concern with the Active Brake Booster solenoid or the related wiring. Diagnose the concern using normal diagnostics in SI.

If the DTC C0299 sets occasionally while driving or when using the cruise control feature, the concern is most likely related to a vacuum leak. Diagnose the concern using normal diagnostics in SI. DTC C0299 diagnostics should lead to the Brake Assist System Diagnosis process to investigate for a possible vacuum leak. Follow the Brake Assist System Diagnosis process to determine if a vacuum leak is present and what the appropriate repair is to fully restore the Brake Assist System.

*******The following is for 2008 MODEL YEAR ONLY.*********

Please use the following for assistance in diagnosing the cause:

DTC C0299 00 is an electrical concern with the Active Brake Booster solenoid or the related wiring. Diagnose the concern using normal diagnostics in SI.

DTC C0299 5A is related to a vacuum leak. Diagnose the concern using normal diagnostics in SI. DTC C0299 diagnostics should lead to the Brake Assist System Diagnosis process. New TECH 2 vacuum sensor data information is available for this concern (Tech 2 Software version 28.001 or greater). Follow the Brake Assist System Diagnosis process to determine if a vacuum leak is present and what the appropriate repair is to fully restore the Brake Assist System.

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.