Diagnosis & Testing: Notes

When ABS control unit detects a problem and indicator light comes on, ABS control unit will store a DTC. See RETRIEVING TROUBLE CODES . ABS control unit can store any number of DTCs. DTCs are indicated in order of ascending number. DTCs are memorized in EEPROM (non-volatile memory). DTCs cannot be erased from memory by disconnecting battery. See CLEARING TROUBLE CODES . When 2 or more DTCs are stored in ABS control unit, trouble shoot DTCs in order of appearance. If a complaint cannot be verified on vehicle, establish conditions present when ABS indicator light came on. If possible, test drive vehicle under similar conditions. If ABS indicator light does not come on during test drive, check for loose connectors and/or terminals. Shake harnesses and connectors while performing diagnosis. Performing ABS diagnosis while ABS indicator light is off could lead to incorrect repairs.