| Subject: | Service Brake Booster Message |
| Models: | 2003-2006 Cadillac Escalade, Escalade EXT, Escalade ESV |
| 2003-2006 Chevrolet Avalanche, Suburban, Tahoe |
| 2003-2007 Chevrolet Silverado Classic |
| 2003-2007 GMC Sierra Classic |
| 2003-2006 GMC Yukon, Yukon Denali, Yukon XL, Yukon Denali XL |
This PI is being updated to add model years and to update the Condition/Concern field. Please discard PIT3568A.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
The Service Brake Booster Message is used to notify the driver of a Supplemental Brake Assist (SBA) concern on vehicles equipped with rear disk brakes and a vacuum brake booster. There have been reports of the Service Brake Booster Message being displayed
on vehicles which do not use the SBA system. During normal diagnostics, a DTC C0136 may be present in the IPC. This DTC will not be in eSI if working on a 2004-2006 utility vehicle, due to all utilities use a hydroboost brake systems starting in 2004. Also
note that starting in 2005; the Silverado and Sierra no longer use the SBA on vehicles with rear drum brakes and vacuum brake booster. This message could be caused by the IPC not being programmed correctly. If the IPC was replaced on a previous unrelated repair
and was not SPS programmed then this message will be displayed after the IPC does not receive a valid health signal from the SBA for 5 consecutive ignition cycles.
Recommendation/Instructions:
To correct this concern, SPS program the IPC. To check and make sure the vehicle is repaired cycle the ignition to off and run at less 5 consecutive times, delaying in each position at least 30 seconds.
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.
