DTC 74

EVO Actuator Circuit:

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 74 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 74 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 a short to voltage in the EVO actuator control circuit.
2. Checks for a shorted actuator solenoid or shorted actuator circuits.
3. Ensures malfunction was not due to physical damage of the EVO actuator circuitry.
4. Isolates the malfunction to either the actuator solenoid or its 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.