Magnasteer/Variable Effort Steering (VES)

CIRCUIT DESCRIPTION
When the Electronic Brake Control Module/Electronic Brake Traction Control Module (EBCM/EBTCM) commands the electronic brake control relay ON, battery voltage is supplied through the EBCM/EBTCM connector C1 terminal B8 to the MAGNASTEER actuator connector terminal A. Ground/control for the MAGNASTEER actuator is provided through the EBCM/EBTCM connector C1 terminal B7 to MAGNASTEER actuator connector terminal B. The EBCM/EBTCM controls the amount of current supplied to the MAGNASTEER actuator based on input from the wheel speed sensors.

CONDITIONS FOR SETTING THE DTC
DTC C1274 can be set once the electronic brake control relay is commanded ON. A malfunction exists if an voltage drop greater than 2.5 volts exists across the MAGNASTEER actuator driver.

ACTION TAKEN WHEN THE DTC SETS
A malfunction DTC is stored and the power steering returns to full assist when DTC C1274 is set. No action towards the ABS warning indicator is taken and the ABS/ETS system is not disabled.

CONDITIONS FOR CLEARING THE DTC
DTC C1274 setting conditions no longer exist when the ignition is turned to the OFF position.



DIAGNOSTIC AIDS
Possible causes:
^ Short to voltage in any of the MSVA actuator circuit wires.
^ Malfunctioning MSVA 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.

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 wing harness.

Important: J 39200 test leads must be zeroed prior to making any resistance measurements. Refer to J 39200 users manual.

After diagnosis is complete, clear the DTCs and test drive the vehicle for 3 drive cycles to verify that the DTC does not reset. A drive cycle consists of starting the vehicle, driving the vehicle over 16 km/h (10 mph), stopping and then turning the ignition to OFF.