TCS Off Indicator On With No DTC Set

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Part 2 Of 2:

CIRCUIT DESCRIPTION
The TCS OFF indicator is controlled by the Electronic Brake Traction Control Module (EBTCM) by sending Class 2 messages to the Instrument Panel Cluster (IPC). It is turned on when the EBTCM sets a Diagnostic Trouble Code (DTC) that turns on the TCS OFF indicator. It is also turned on or off when the Traction Control Switch is pressed. The EBTCM supplies 12 volts to the Traction Control Switch, when the TCS switch is depressed the EBTCM sees the voltage go low, and that the TCS switch state has changed. When the EBTCM receives that a switch state has changed it turns on or off the Traction Control and sends a message to the IPC to turn on or off the TCS OFF indicator depending on its previous state.

DIAGNOSTIC AIDS
^ It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.
^ Thoroughly inspect any circuitry that may be causing the complaint for the following conditions:
- Backed out terminals
- Improper mating
- Broken locks
- Improperly formed or damaged terminals
- Poor terminal-to-wiring connections
- Physical damage to the wiring harness

^ The following conditions may cause an intermittent malfunction:
- A poor connection
- Rubbed-through wire insulation
- A broken wire inside the insulation

^ If an intermittent malfunction exists refer to Troubleshooting Procedures in Diagnostic Aids for further diagnosis.

TEST DESCRIPTION
The number(s) below refer to the step number(s) on the diagnostic table.
2. Checks if Electronic Brake (and Traction) Control Module (EBCM/EBTCM) is receiving a Traction Control Switch message from the switch.
3. Checks if the Scan tool can turn on and off all the indicator lamps in the instrument cluster.
5. Checks if the EBCM/EBTCM or Traction Control Switch is at fault.