Self-Diagnostic System

ABS control unit performs 2 self-diagnostic functions. Initial diagnosis is performed from the time engine starts until ABS indicator lights go off. Regular diagnosis is continuously performed from time indicator lights go off on start-up until ignition is turned off. When a problem is detected, ABS control unit will turn ABS indicator light on, go into fail-safe mode, stop ABS control, and memorize DTC.

When ABS modulator/control unit detects a problem and either indicator light comes on, ABS modulator/control unit will store a DTC. ABS modulator/control unit can store any number of DTCs. The DTCs are indicated in order of ascending number. DTCs are memorized in EEPROM (non-volatile memory) and cannot be erased from memory by disconnecting battery. See CLEARING DIAGNOSTIC TROUBLE CODES  under DIAGNOSIS & TESTING. When 2 or more DTCs are stored in ABS modulator/control unit, trouble shoot DTCs in order of appearance. If complaint cannot be verified, establish conditions present when indicator light came on. If possible, test drive vehicle under similar conditions. If neither indicator light comes on during test drive, check for loose connectors and/or terminals. Shake wiring and connectors while diagnosing. Attempting to follow diagnostic test procedures when indicator is not lit may lead to faulty diagnosis.