Diagnostic Aids
WARNING: This page is about a different car, the 2007 Hummer H2. However, it is still accessible from the selected car via links, so may be relevant.
Press and release the TC2 mode switch several times while observing the traction LED switch telltale in order to verify that the TC2 full traction limited status changes each time the switch is pressed and that DTC B3626 does not set. Using the scan tool in order to observe the Mode Switch Pressed or Released status may also be helpful in diagnosing an intermittent fault within the switch.
Thoroughly inspect connections or circuitry that may cause an intermittent malfunction. Refer to Testing for Electrical Intermittents , Testing for Intermittent Conditions and Poor Connections , Wiring Repairs and Connector Repairs .