Antilock Braking System (ABS)

DTC 15 Enable Relay Contacts Shorted To Battery:

CIRCUIT DESCRIPTION
Ignition voltage is supplied through terminal "86" of the ABS enable relay. The EBCM then is able to energize the pull-in coil by completing the ground circuit at Pin "22" of the EBCM. The magnetic field created closes the enable relay contacts and allows battery voltage and current to be supplied to the EMB's and EBCM, which supplies power to the motors and solenoids.

FAILURE CONDITION
DTC A015 can be set only before the EBCM commands the relay "ON." This test determines if the enable relay is energized when it should not be. This malfunction would not allow the enable relay to remove power to the ABS system. If a second malfunction were to occur that requires the enable relay to be turned "OFF" that malfunction can not be removed if the relay can not be controlled. The malfunction must be present for three consecutive drive cycles before the DTC is set.

ACTION TAKEN
A malfunction DTC is stored. ABS is not disabled; however, the ABS indicator lamp will flash to indicate a malfunction exists.

TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This step indicates that the EBCM is capable of controlling the enable relay as commanded.
2. This step checks for voltage at terminal "A" of the 2-way EBCM harness connector. if voltage is present, the malfunction exists in the enable relay and/or its circuitry.
3. This test checks for a short to ground in the enable relay control circuit.
4. This step checks for a short to voltage in CKT 850.
5. This step identifies if the EBCM is malfunctioning.

DIAGNOSTIC AIDS
An "Intermittent" malfunction may be caused by a poor connection, rubbed through wire insulation, or a wire that is broken inside the insulation.

The frequency of the malfunction can be checked by using the enhanced diagnostic function of the Tech 1.

Any circuitry, that is suspected as causing the intermittent complaint, should be thoroughly checked for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wiring connections or physical damage to the wiring harness.