A018

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 EMBs and 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, solenoids and EMBs. A malfunction of this type will not allow voltage to be available to the motors, solenoids and EMBs; 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 if the EBCM is capable of controlling the enable relay as commanded.
2. With the enable relay removed, voltage should not be available at terminal "85". Any voltage at this point would indicate that CKT 879 was shorted to a voltage source.
3. This step checks for a shorted coil.
4. This ensures malfunction was not due to a poor connection.

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.