Symptom Chart — Brake System
| Condition
| Possible Sources
| Action
|
|---|
- The red brake warning indicator and the yellow ABS warning indicator are illuminated
| | |
- 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)
| |
- Vehicle pulls or drifts during braking
| - Brake calipers and/or guide pins
- Brake flexible hose
- Brake pads
- Brake discs
| |
| | |
| - Suspension component(s) and/or wheel alignment
| |
- 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
in this section.
|
| | - CARRY OUT the Brake Master Cylinder — Bypass Condition Component Test in this section.
|
| - Hydraulic Control Unit (HCU)
| |
- Brakes lock up under light brake pedal force
| - Brake pads
- Brake flexible hose
- Brake disc
- Brake calipers and/or guide pins
| |
| | |
- 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
in this section.
|
| | - CARRY OUT the Brake Master Cylinder — Bypass Condition Component Test in this section.
|
| - Brake calipers and/or guide pins
| |
| | |
- Erratic brake pedal travel
| | - 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
Section 206-06
.
|
| | |
| | |
| - Brake caliper and/or guide pins
- Brake flexible hose
| |
| - Brake booster
- Brake master cylinder
| - CARRY OUT the Brake Master Cylinder — Compensator Port Component Test in this section.
|
| | |
| | - VERIFY correct installation of the stoplamp switch. REFER to
Section 417-01
.
|
- 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 section.
|
| | |
Symptom Chart — NVH
NOTE:
NVH symptoms should be identified using the diagnostic tools that are available. For a list of these tools, an explanation of their uses and a glossary of common terms, refer to
Section 100-04
. Since it is possible any one of multiple systems may be the cause of a symptom, it may be necessary to use a process of elimination type of diagnostic approach to pinpoint the responsible system. If this is not the causal system for the symptom, refer back to
Section 100-04
for the next likely system and continue diagnosis.
| Condition
| Possible Sources
| Action
|
|---|
- Vibration when the brakes are applied
| - Brake disc(s)
- Suspension components
| |
- Brake vibration/shudder — occurs when the brake pedal is released
| | |
| - Caliper guide pins or guide pin bolts
| |
| - Missing or damaged anti-rattle clips or springs
| - CHECK the brake pads for missing clips or broken springs. INSTALL new components as necessary. REFER to
Section 206-03
for front disc brakes or
Section 206-04
for rear disc brakes.
|
| | |
- Squealing noise — occurs on first (morning) brake application
| | - Acceptable condition. Caused by humidity and low brake pad temperature.
|
- Squealing noise — a continuous squeal
| | |
- Squealing noise — an intermittent squeal
| | - Acceptable condition. Caused by cold, heat, water, mud or snow.
|
- Groaning noise — occurs at low speeds with brake lightly applied (creeping)
| | |
- Grinding/moaning noise — continuous
| | - INSPECT the brake pads, brake discs and attaching hardware for damage. VERIFY brake components are within specifications. REFER to
Brake System Inspection
in this section.
|