Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Anti-Lock Brake System: Description: Notes
The Anti-Lock Brake System (ABS) consists of an ABS control unit, hydraulic modulator, system relays, speed sensors and necessary wiring. See Fig 1 .
When brake pedal is applied, the ECM monitors input signals from each wheel Vehicle Speed Sensor (VSS). If ECM senses wheel lock-up, it will output a signal to appropriate solenoid valve. Each solenoid valve allows hydraulic pressure to increase or decrease to the appropriate brake caliper.
If a system failure occurs, the ANTILOCK warning light, located on instrument panel, will illuminate. System will be deactivated, but conventional brake system will still operate.
Use the Manual With the Right Hardware
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.