DTC 18

18 ABS RELAY COIL CIRCUIT SHORTED TO BATTERY

DTC 18 ABS Relay Coil Circuit Shorted To Battery:

DTC 18 ABS Relay Coil Circuit Shorted To Battery:

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 18 can be set after the EBCM commands the ABS relay "ON." This test monitors the availability of current/voltage to the motors and solenoids. A malfunction of this type will not allow voltage to be available to the motors and solenoids; therefore, ABS operation would not be allowed if required.

ACTION TAKEN:
A malfunction DTC is stored, ABS is disabled and the amber ABS warning lamp is turned "ON." The red BRAKE warning lamp is turned "ON" if the rear piston in the ABS motor pack is not in the home position.

DTC CHART TEST DESCRIPTION:
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Indicates that the EBCM is capable of controlling the ABS relay as commanded.
2. Checks for a short to voltage on the ABS relay control circuit.
3. Verifies that the ABS relay coil has the appropriate resistance.
4. Verifies that the relay contacts are not failed closed.
5. Checks for possible poor terminal contact at the EBCM.

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