Anti-Lock Brake System: Diagnosis: Notes

ABS can only be diagnosed using ABS Tester (0000-42-0010) and Adapter Harness (49-N066-001 for Miata, or 49-H066-003 for 929). ABS tester cannot diagnose ABS control unit. If a malfunction is detected in ABS and all other components in brake system are okay, replace ABS control unit.

If ABS tester is unavailable, test each component of ABS. See test procedures under TESTING. If all ABS components test okay, replace control unit with a known good unit and retest system.