Symptom Chart

Condition	Possible Sources	Action
No communication with the ABS module	Fuse ABS module Wiring, terminals or connectors	REFER to MODULE COMMUNICATIONS NETWORK article to diagnose the no communication problem.
Poor vehicle tracking during anti-lock function	Air in brake hydraulic system Hydraulic control unit (HCU)	Go to Pinpoint Test F .
	Base brake system	REFER to Diagnosis and Testing in BRAKE SYSTEM - GENERAL INFORMATION article.
The traction control is inoperative	ABS module	Go to Pinpoint Test G .
	Base brake system	REFER to Diagnosis and Testing in BRAKE SYSTEM - GENERAL INFORMATION article.
The yellow ABS warning indicator does not self-check	Instrument cluster Wiring, terminals or connectors	REFER to INSTRUMENT CLUSTER article to diagnose the instrument cluster.
The yellow ABS warning indicator and the red brake warning indicator are illuminated	ABS module connector not connected	CONNECT the ABS module connector C135.
	DTCs present in the ABS module	Go to the ABS MODULE DTC CHART .
Traction control indicator is always/never on	ABS module Wiring, terminals or connectors Instrument cluster	REFER to INSTRUMENT CLUSTER article to diagnose the instrument cluster.
The traction control cannot be disabled	Wiring, terminals or connectors Traction control switch ABS module	Go to Pinpoint Test G .
Traction control indicator on the switch is always illuminated	Wiring, terminals or connectors Traction control switch ABS module Lighting control module (LCM)	Go to Pinpoint Test I .
Traction control indicator on the switch is never illuminated	Wiring, terminals or connectors Traction control switch ABS module LCM Instrument cluster	RETRIEVE and RECORD any communication DTCs from the ABS module, instrument cluster and LCM. REPAIR any communication DTCs first. If there are no communication DTCs, go to Pinpoint Test J .