Anti-Lock Warning Light: Notes
- Turn ignition on. ANTI-LOCK warning light should blink twice, and then go out. Turn ignition switch to START position. Warning light should come on and stay on.
- When ignition switch is turned from START to ON position, warning light should blink twice and then go out. If warning light functions as specified, go step 3). If warning light does not function as specified, see appropriate trouble shooting test:
- ANTI-LOCK WARNING LIGHT INOPERATIVE.
- IGNITION SWITCH IN ON POSITION, WARNING LIGHT REMAINS ON.
- IGNITION SWITCH IN START POSITION, WARNING LIGHT INOPERATIVE.
- IGNITION SWITCH IN ON POSITION, WARNING LIGHT BLINKS ONCE. IN START POSITION, WARNING LIGHT STAYS ON. WHEN IGNITION SWITCH IS CYCLED FROM START TO ON POSITION, WARNING LIGHT BLINKS ONCE.
- IGNITION SWITCH IN ON POSITION, WARNING LIGHT BLINKS TWICE AND REMAINS OFF.
- WARNING LIGHT SWITCHES OFF ONE SECOND AFTER IGNITION SWITCH IS TURNED TO ON POSITION.
- Test drive vehicle. If ANTI-LOCK warning light does not come on at low speed, go to next step. If ANTI-LOCK warning light comes on at low speed, motor relay, solenoid valve or wheel speed sensor malfunction is indicated. Go to step 6). If insufficient braking force or ABS malfunction exists, go to next step. If none of listed symptoms exist, go to step 6).
- Check conventional brake system components for proper operation. Check for mechanical lock of hydraulic unit solenoid valve. Check for plugged hydraulic line in hydraulic unit. Repair or replace as necessary. If hydraulic unit is okay, go to next step.
- Ensure wheel speed sensor rotor gap is correct. See WHEEL SPEED SENSOR under ADJUSTMENTS. Check for faulty wheel speed sensor. See WHEEL SPEED SENSOR TESTING . Replace sensor as necessary. See procedures under WHEEL SPEED SENSOR R & I . Inspect ECU wiring. See WIRING DIAGRAM . If testing indicates no mechanical or electrical failures, replace ECU.
- Enter ABS self-diagnostics, and retrieve DTCs. See RETRIEVING DTCS under DIAGNOSIS & TESTING. If no DTCs are displayed, fault may be intermittent. Try to make malfunction reoccur. If no diagnostic output exists, check for faulty wiring harness between ECU and data link connector. See WIRING DIAGRAM . Repair or replace as necessary.
NOTE:
Trouble shoot ANTI-LOCK warning light in following sequence: instrument cluster circuit, ECU and valve relay.