Antilock Braking System (ABS)

15 ABS RELAY CONTACT CIRCUIT SHORT TO BATTERY/ALWAYS CLOSED

DTC 15 ABS Relay Contact Circuit Shorted To Battery Or Always Closed:

DTC 15 ABS Relay Contact Circuit Shorted To Battery Or Always Closed:

CIRCUIT DESCRIPTION:
Ignition voltage is supplied through terminal "C10" of the ABS relay. The EBCM then is able to energize the pull-in coil by completing the ground circuit at connector "C1", terminal "A11" of the EBCM. The magnetic field created closes the ABS relay contacts and allows battery voltage and current through the ABS relay terminal "B10" to be supplied to the EBCM through connector "C2", terminal "C", which supplies power to the motors and solenoids.

DTC WILL SET WHEN:
DTC 15 can be set only before the EBCM commands the relay "ON." This test determines if the ABS relay is energized when it should not be. This malfunction would not allow the ABS relay to remove power to the ABS system. If a second malfunction were to occur that requires the ABS relay to be turned "OFF," that malfunction cannot be removed if the relay cannot 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.

DTC CHART TEST DESCRIPTION:
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Checks to see if other DTCs are set.
2. Indicates that the EBCM is capable of controlling the ABS relay as commanded.
3. Checks for a possible short to voltage in CKT 1633.
4. Determines whether the short to voltage is in CKT 1633 or due to a malfunctioning relay.
5. Checks for a possible intermittent in wiring or connectors.

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 of 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.