ABS (DIAGNOSTICS) > General Diagnostic Table
|
Symptom |
Problem parts | |
|
Vehicle instability during braking |
Vehicle is pulled to either right or left side. |
• ABSCM&H/U (solenoid valve) • ABS wheel speed sensor • Brake (caliper, piston and pad) • Wheel Alignment • Tire specifications, tire wear and air pressures • Incorrect wiring or piping connections • Road surface (uneven, camber) |
|
Vehicle spins. |
• ABSCM&H/U (solenoid valve) • ABS wheel speed sensor • Brake (pad) • Tire specifications, tire wear and air pressures • Incorrect wiring or piping connections | |
|
Poor brake performance |
Long braking/stopping distance |
• ABSCM&H/U (solenoid valve) • Brake (pad) • Air in brake line • Tire specifications, tire wear and air pressures • Incorrect wiring or piping connections |
|
Wheel locks. |
• ABSCM&H/U (solenoid valve, motor) • ABS wheel speed sensor • Incorrect wiring or piping connections | |
|
Brake drag |
• ABSCM&H/U (solenoid valve) • ABS wheel speed sensor • Master cylinder • Brake (caliper and piston) • Parking brake • Axle & wheels • Brake pedal play | |
|
Long brake pedal stroke |
• Air in brake line • Brake pedal play | |
|
Vehicle vertical pitching |
• Suspension play or fatigue (reduced damping) • Incorrect wiring or piping connections • Road surface (uneven) | |
|
Unstable or uneven braking |
• ABSCM&H/U (solenoid valve) • ABS wheel speed sensor • Brake (caliper, piston and pad) • Tire specifications, tire wear and air pressures • Incorrect wiring or piping connections • Road surface (uneven) | |
|
Vibration and/or noise (while driving on slippery roads) |
Excessive pedal vibration |
• Incorrect wiring or piping connections • Road surface (uneven) |
|
Noise from the ABSCM&H/U |
• ABSCM&H/U (mount bushing) • ABS wheel speed sensor • Brake line | |
|
Noise from front of vehicle |
• ABSCM&H/U (mount bushing) • ABS wheel speed sensor • Master cylinder • Brake (caliper, piston, pad and rotor) • Brake line • Brake booster and check valve • Suspension play or fatigue | |
|
Noise from rear of vehicle |
• ABS wheel speed sensor • Brake (caliper, piston, pad and rotor) • Parking brake • Brake line • Suspension play or fatigue | |