Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 13 other vehicles, including the 2003 Hummer H2, 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 GMC Sierra, and 2003 GMC Cab & Chassis Sierra. However, it is still accessible from the selected car via links, so may be relevant.

Inspect the TAC module connectors for signs of water intrusion. If water intrusion occurs, multiple DTCs may set without any circuit or component conditions found during diagnostic testing.
The APP sensor 1 and the Throttle Position (TP) sensor 1, 5-volt reference circuits are internally connected within the TAC module.
The APP sensor 2 and the TP sensor 2, 5-volt reference circuits are internally connected within the TAC module.
When the TAC module detects a condition within the TAC system more than 1 TAC system related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing 1 individual condition may correct more than 1 DTC. Remember this if you review the information stored in Captured Info.
If an intermittent condition is suspected, see INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM.