Circuit Description
The seat adjuster motors are controlled by the driver seat module (DSM) through the adjuster motor control circuits. In an inactive state both of the motor control circuits are grounded within the DSM. In an active state the DSM 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 DSM also monitors the current flow through the motor control circuits.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC B1770 Driver Seat Motor Horizontal Circuit |
| • | DTC B1775 Driver Seat Motor Front Vertical Circuit |
| • | DTC B1780 Driver Seat Motor Rear Vertical Circuit |
| • | DTC B1785 Driver Seat Motor Recline Circuit |
| • | DTC B1790 Driver Seat Motor Lumbar Circuit |
| • | DTC B1805 Driver Seat Motor Side Bolster Circuit |
Conditions for Running the DTC
The system voltage must be between 9-16 volts.
Conditions for Setting the DTC
The motor control circuit monitored by the DSM is determined to be shorted to ground, battery positive voltage, or open.
Action Taken When the DTC Sets
| • | 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. |
Diagnostic Aids
When an adjuster motor control circuit is shorted to ground the DSM will also set a DTC B3962.
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Driver Seat Schematics Connector End View Reference: Power Seat Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 | Verify the condition is present. Does the system operate normally? | Go to Testing for Intermittent Conditions and Poor Connections | Go to Step 3 |
3 |
Does the test lamp illuminate when the switch is activated in both directions? | Go to Step 5 | Go to Step 4 |
4 | Test the motor control circuits for an open or short to ground. Refer to Circuit Testing and to Wiring Repairs. Did you find and correct the condition? | Go to Step 9 | Go to Step 6 |
5 | Inspect for poor connections at the adjuster motor connector. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs. Did you find and correct the condition? | Go to Step 9 | Go to Step 7 |
6 | Inspect for poor connections at the harness connector of the driver seat module (DSM). Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs. Did you find and correct the condition? | Go to Step 9 | Go to Step 8 |
7 | Replace the appropriate adjuster motor assembly. Refer to Front Seat Adjuster Motor Replacement . Did you complete the replacement? | Go to Step 9 | -- |
8 | Replace the DSM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 9 | -- |
9 |
Does the DTC reset? | Go to Step 3 | System OK |
