Symptom Chart - Brake System
WARNING: This page is about a different car, the 2016 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.
| Condition | Possible Sources | Action |
|---|---|---|
| The red brake warning indicator and the yellow ABS warning indicator are illuminated | DTCs in the ABS module | REFER to Anti-Lock Brake System (ABS) and Stability Control 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) Vacuum sensor Electronic Brake Distribution(EBD) |
REFER to Instrumentation, Message Center, and Warning Chimes to diagnose the red brake warning indicator. |
| Vehicle pulls or drifts during braking | Tires | REFER to Wheels and Tires to diagnose tire concerns. |
| Brake calipers and/or guide pins Brake flexible hose Brake pads Brake discs |
INSPECT the brake system components. REFER to Brake System Inspection . | |
| 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 . | |
| Hydraulic Control Unit(HCU) | REFER to Anti-Lock Brake System (ABS) and Stability Control to diagnose the HCU. | |
| Brakes lock up under light brake pedal force | Brake pads Brake flexible hose Brake disc Brake calipers and/or guide pins |
INSPECT the brake system components. REFER to Brake System Inspection . |
| ABS | REFER to Anti-Lock Brake System (ABS) and Stability Control to diagnose the ABS. | |
| 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 . |
| Brake master cylinder | CARRY OUT the Brake Master Cylinder - Bypass Condition . | |
| 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 . | |
| HCU | REFER to Anti-Lock Brake System (ABS) and Stability Control to diagnose the HCU. | |
| Erratic brake pedal travel | Brake pedal | INSPECT the brake pedal for binding, obstructions and correct connection to booster rod. REPAIR as necessary. CHECK the brake pedal fasteners for correct torque. REFER to Specifications in Hydraulic Brake Actuation . |
| ABS | REFER to Anti-Lock Brake System (ABS) and Stability Control to diagnose the ABS. | |
| Brakes drag | Stoplamp switch | VERIFY correct installation of the stoplamp switch. REFER to Exterior Lighting . |
| Parking brake component | REFER to Parking Brake and Actuation to diagnose the parking brake system. | |
| Brake caliper and/or guide pins | INSPECT the brake caliper and guide pins. REFER to Brake System Inspection . | |
| Brake booster/Master cylinder | CARRY OUT the Brake Master Cylinder - Compensator Port . | |
| HCU | REFER to Anti-Lock Brake System (ABS) and Stability Control to diagnose the HCU. | |
| Excessive brake pedal effort | Insufficient engine vacuum for brake booster operation Brake booster manifold vacuum hose Brake booster Brake booster vacuum sensor/check valve Brake vacuum pump |
CARRY OUT the Brake Booster Component Test. If any DTCs are retrieved for the brake vacuum pump, resolve them first before attempting any base brake repairs. |
| Brake pads | INSPECT the brake pads. REFER to Brake System Inspection . | |