Symptom Chart - Brake System

BRAKE SYSTEM SYMPTOM CHART

Condition	Possible Sources	Action
The red brake warning indicator and the yellow ABS warning indicator are illuminated	DTCs in the ABS module	REFER to VEHICLE DYNAMIC SYSTEMS to diagnose the ABS.
The red brake warning indicator is always/never on	Brake fluid level switch Parking brake switch Wiring, terminals or connectors Instrument Cluster (IC) Smart Junction Box (SJB) Electronic Brake Distribution (EBD)	REFER to INSTRUMENTATION AND WARNING CHIMES to diagnose the red brake warning indicator.
Brakes drag	Parking brake component	REFER to PARKING BRAKE & ACTUATION to diagnose the parking brake system.
	Incorrect brake shoe and/or parking brake cable adjustment	ADJUST the brake shoes and parking brake cables. REFER to Parking Brake Cable Adjustment in PARKING BRAKE & ACTUATION .
	Wheel cylinder(s) Brake flexible hose Brake caliper and/or guide pins	INSPECT the brake system components. REFER to BRAKE SYSTEM INSPECTION .
	Brake booster Brake master cylinder	CARRY OUT the Brake Master Cylinder - Compensator Port Component Test.
	Hydraulic Control Unit (HCU)	REFER to VEHICLE DYNAMIC SYSTEMS to diagnose the HCU .
	Stoplamp switch	VERIFY correct installation of the stoplamp switch. REFER to EXTERIOR LIGHTING .
Brakes lock up under light brake pedal force	Stoplamp switch	VERIFY correct installation of the stoplamp switch. REFER to EXTERIOR LIGHTING .
	Brake calipers and/or guide pins Wheel cylinders and/or brake hardware Brake flexible hose Brake pads/shoes Brake discs/drums	INSPECT the brake system components. REFER to BRAKE SYSTEM INSPECTION .
	ABS	REFER to VEHICLE DYNAMIC SYSTEMS to diagnose the ABS.
Vehicle pulls or drifts during braking	Brake calipers and/or guide pins Wheel cylinders and/or brake shoe hardware Brake flexible hose Brake pads/shoes Brake discs/drums	INSPECT the brake system components. REFER to BRAKE SYSTEM INSPECTION .
	Tires	REFER to WHEELS & TIRES to diagnose tire concerns.
	Suspension component(s) and/or wheel alignment	REFER to SUSPENSION SYSTEM-GENERAL INFORMATION to diagnose suspension system.
Brake pedal goes down fast or eases down slowly	Brake fluid leaks and/or air in the system	INSPECT the system for leaks. REPAIR as necessary. BLEED the system. REFER to BRAKE SYSTEM BLEEDING .
	Brake master cylinder	CARRY OUT the Brake Master Cylinder - Bypass Condition Component Test.
	HCU	REFER to VEHICLE DYNAMIC SYSTEMS to diagnose the HCU .
Excessive brake pedal travel (low/spongy pedal)	Brake fluid leaks and/or air in the system	INSPECT the system for leaks. REPAIR as necessary. BLEED the system. REFER to BRAKE SYSTEM BLEEDING .
	Incorrect brake shoe adjustment	REFER to DRUM BRAKE for the brake shoe adjustment procedure.
	Brake master cylinder	CARRY OUT the Brake Master Cylinder - Bypass Condition Component Test.
	Brake calipers and/or guide pins	INSPECT the brake calipers and guide pins. REFER to BRAKE SYSTEM INSPECTION .
	Brake flexible hose	INSPECT the brake flexible hoses during brake application. REFER to BRAKE SYSTEM INSPECTION .
Erratic brake pedal travel	Brake pedal	INSPECT the brake pedal for binding, obstructions and correct installation. REPAIR as necessary. CHECK the brake pedal fasteners for correct torque. REFER to Specifications in HYDRAULIC BRAKE ACTUATION .
Erratic brake pedal travel	ABS	REFER to VEHICLE DYNAMIC SYSTEMS to diagnose the ABS.
Excessive brake pedal effort	Insufficient vacuum for brake booster operation Brake booster manifold vacuum hose Brake booster Brake booster check valve	CARRY OUT the Brake Booster Component Test.
Excessive brake pedal effort	Brake pads/shoes	INSPECT the brake pads/shoes. REFER to BRAKE SYSTEM INSPECTION .