Magnasteer/Variable Effort Steering (VES)

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CIRCUIT DESCRIPTION
Battery voltage is supplied to the EVO actuator terminal A when the Electronic Brake Control Module (EBCM) commands the ABS enable relay ON. Ground for the EVO actuator is provided through EBCM terminal 18 to actuator terminal B. The EBCM controls the amount of current supplied to the EVO actuator bases on input from the ABS wheel speed sensors and the steering wheel position sensor.

CONDITIONS FOR SETTING THE DTC
DTC C1273 can be set before ABS initialization or above 16 km/h (10 mph). Before initialization, if the EBCM detects the EVO actuator control circuit is at ground, a malfunction exists. Above 16 km/h (10 mph), if the EVO actuator sense current is less than half the command current, a malfunction exists, Refer to Brakes and Traction Control.

ACTION TAKEN WHEN THE DTC SETS
A malfunction DTC is stored, ABS/VES is disabled, and the ABS indicator lamp is turned ON and power steering returns to full assist.

CONDITIONS FOR CLEARING THE DTC
DTC C1273 setting conditions no longer exist and the ignition key is turned OFF.



DIAGNOSTIC AIDS
Possible causes:
- Open or short to ground in any of the EVO actuator circuit wires.
- Malfunctioning EVO actuator.
Ensure all ABS DTCs are diagnosed and corrected prior to clearing VES DTCs. Clearing VES DTCs will automatically clear ABS DTCs resulting in a loss of DTC history data.

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 Scan Tool, as described in Enhanced Diagnostics, found in this section.

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.