Circuit Description

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.

The traction control system (TCS) TRAC OFF indicator is controlled by the instrument panel cluster (IPC) via class 2 serial data messages from the electronic brake control module (EBCM). When the EBCM sees the TCS switch fault, the EBCM then disables the TCS, and sends a message to the IPC to turn the TRAC OFF indicator ON. Each time the ignition is cycled from OFF to ON, the TCS is enabled.

The following conditions will cause the TRAC OFF indicator to illuminate:

The EBCM has disabled the TCS due to a DTC.
The EBCM has disabled the TCS due to a overheated ABS/TCS hydraulic unit.
The IPC bulb check. When the ignition switch is turned to ON, the TRAC OFF indicator will turn ON for approximately 5 seconds and then turn OFF.