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A018

Diagnostic Chart:




Wiring Diagram:






CIRCUIT DESCRIPTION
Ignition voltage is supplied through terminal "A2" of the ABS enable relay. The Electronic Brake Control Module (EBCM) then is able to energize the pull-in coil by completing the ground circuit at terminal "22" of the EBCM. The magnetic field created closes the enable relay contacts and allows battery voltage and current to be supplied to the EBCM, which supplies voltage to the motors and solenoids.

FAILURE CONDITION
DTC A018 can be set after the EBCM commands the enable 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 ABS indicator lamp is turned "ON."

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 a short to B + on the relay control circuit.
3. This step verifies that the relay coil has the appropriate resistance.
4. This step checks for possible poor terminal contact at the EBCM.
5. This step checks for additional DTCs present.

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.