DTC 73

DTC 73 EVO Actuator Circuit Open Or Shorted To Ground (For ABS With VES Only):

EVO Actuator Circuit (For ABS With VES Only):

CIRCUIT DESCRIPTION
Battery voltage is supplied to Electronic Variable Orifice (EVO) actuator terminal "A" when the Electronic Brake Control Module (EBCM) commands the Antilock Braking System (ABS) enable relay "ON." Ground for the EVO actuator is provided through EBCM terminal "11," to actuator terminal "B". The EBCM controls the amount of current supplied to the EVO actuator based on input from the wheel speed sensors and the steering wheel speed sensor.

DTC WILL SET WHEN
DTC 73 can be set anytime after ABS initialization. A malfunction exists if an excessive voltage drop is across the EVO actuator driver.

ACTION TAKEN
A malfunction DTC is stored, VES is disabled and power steering returns to full assist.

DTC WILL CLEAR WHEN
DTC 73 setting conditions no longer exist and the ignition key is turned "OFF."

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. Checks for proper operation of the EVO sensor.
2. Checks for high resistance in the EVO actuator control circuit.
3. Checks for a short to ground in the EVO actuator control circuit.
4. Checks for high resistance in the EVO actuator control circuit.
5. Checks for a short to ground in the EVO actuator control circuit.
6. Checks for a short to ground in the EVO actuator.
7. Checks for a open in the EVO actuator.
8. Ensures open or short to ground was not due to physical damage of the EVO actuator circuitry.

DIAGNOSTIC AIDS
An "Intermittent" malfunction is most likely 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 malfunction, 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.