B1805

CIRCUIT DESCRIPTION
The seat adjuster motors are controlled by the memory seat module through the adjuster motor control circuits. In an inactive state both of the motor control circuits are grounded within the memory seat module. In an active state the memory seat module switches the appropriate motor control circuit to battery positive voltage. The direction of the adjuster motor rotation is determined by which of the motor control circuits is switched to battery positive voltage while the other remains grounded. During adjuster motor operation the memory seat module also monitors the current flow through the motor control circuits.

The memory seat module monitors the positions of the horizontal, front vertical, and rear vertical adjuster motors using hall effect type position sensors. The hall effect position sensors are supplied with 5-volt reference and ground circuits from the memory seat module. The position sensor signal circuits are supplied 5-volts through a resistor then monitored within the memory seat module. During adjuster motor operation the hall effect position sensor provides a single pulse for every adjuster motor shaft rotation. The memory seat module counts the pulses from the position sensor signal circuits to determine the adjuster motor positions when storing or recalling memory seat position settings.

CONDITIONS FOR RUNNING THE DTC
The system voltage must be between 9.0 and 16.0 volts.

CONDITIONS FOR SETTING THE DTC
^ The memory seat module does not detect position sensor movement during adjuster motor operation.
^ The motor control circuit monitored by the memory seat module is determined to be shorted to ground, battery positive voltage, or open.

ACTION TAKEN WHEN THE DTC SETS
^ The memory recall functions for the seat motor with a current status DTC will be disabled.
^ When the fault is no longer present a history status DTC will be stored, and motor operation will be restored.

CONDITIONS FOR CLEARING THE DTC
^ The DTC will be current for as long as the fault is present.
^ When the fault is no longer present the DTC will be a history status code.
^ The history DTC will be cleared after 100 error free ignition cycles, or by using the scan tool clearing DTCs feature.

TEST DESCRIPTION

Steps 1-8:

Steps 9-16:

The numbers below refer to the step numbers on the diagnostic table.
3. This step determines if the DTC is set as the result of an adjuster motor fault or a position sensor fault.
6. During this test the memory seat module must see an active switch input before power will be supplied the position sensor.
7. During this test the memory seat module must see an active switch input before power will be supplied the position sensor.
8. During this test the memory seat module must see an active switch input before power will be supplied the position sensor.