Symptom Chart - Brake System (Non-Hybrid Vehicles)

WARNING: This page is about a different car, the 2010 Mercury Mariner and 2010 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

SYMPTOM CHART - BRAKE SYSTEM (NON-HYBRID VEHICLES)

Condition	Possible Sources	Action
The red brake warning indicator and the yellow ABS warning indicator are illuminated	DTCs in the ABS module	REFER to DIAGNOSIS AND TESTING 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 DIAGNOSIS AND TESTING to diagnose the red brake warning indicator.
Brakes drag	Parking brake component	REFER to DIAGNOSIS AND TESTING to diagnose the parking brake system.
	Incorrect brake shoe adjustment	REFER to DIAGNOSIS AND TESTING for the brake shoe adjustment procedure.
	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 in this article.
	Hydraulic Control Unit (HCU)	REFER to DIAGNOSIS AND TESTING to diagnose the HCU .
	Stoplamp switch	VERIFY correct installation of the stoplamp switch. REFER to STOPLAMP SWITCH .
Brakes lock up under light brake pedal force	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 .
Brakes lock up under light brake pedal force	Anti-lock brake system	REFER to DIAGNOSIS AND TESTING 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 DIAGNOSIS AND TESTING to diagnose tire concerns.
	Suspension component(s) and/or wheel alignment	REFER to DIAGNOSIS AND TESTING 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 Component Test in this article.
	HCU	REFER to DIAGNOSIS AND TESTING 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 BRAKE SHOE ADJUSTMENT for the brake shoe adjustment procedure.
	Brake master cylinder	CARRY OUT the Brake Master Cylinder Component Test in this article.
	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 SPECIFICATIONS .
Erratic brake pedal travel	Anti-lock brake system	REFER to DIAGNOSIS AND TESTING 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 in this article.
Excessive brake pedal effort	Brake pads	INSPECT the brake pads. REFER to BRAKE SYSTEM INSPECTION .