Symptom Chart

Condition	Possible Sources	Action
No communication with the ABS module	Circuitry ABS module	REFER to MODULE COMMUNICATIONS NETWORK article to diagnose the no communication problem.
The red brake warning indicator and the yellow ABS warning indicator are both illuminated	DTCs present in the ABS module	REFER to ABS Module DTC Chart .
The red brake warning indicator is illuminated and the yellow ABS warning indicator is not illuminated	Circuitry Parking brake Brake fluid level sensor Instrument cluster ABS module	REFER to BRAKE SYSTEM - GENERAL INFORMATION article to diagnose the red brake warning indicator.
The ABS warning indicator is never/always on	Circuit Instrument cluster ABS module	REFER to INSTRUMENT CLUSTER (IC), MESSAGE CENTER, AND WARNING CHIMES article to diagnose the instrument cluster.
ABS false activation at low speeds or near the end of stopping the vehicle.	ABS wheel speed sensor tone ring	INSPECT the tone rings, INSTALL new as necessary.
Spongy brake pedal with no warning indicator	Air in brake hydraulic system Base brakes	REFER to Diagnosis and Testing in BRAKE SYSTEM - GENERAL INFORMATION article.