Circuit Description
The seat adjuster motors are controlled by the memory seat module (MSM) through the power seat motor control circuits. The MSM also monitors current flow through the motor control circuits. In an active state the motor control circuits are switched to power and ground within the MSM. The direction of the adjuster motor rotation is determined by which of the control circuits are switched to battery positive voltage and which are grounded.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC B1770 Seat Motor Horizontal Circuit |
| • | DTC B1775 Seat Motor Front Vertical Circuit |
| • | DTC B1780 Seat Motor Rear Vertical Circuit |
| • | DTC B1785 Seat Motor Recline Circuit |
Conditions for Running the DTC
| • | The MSM detects a switch signal active or a memory function request and supplies voltage to the power seat motor control circuits |
| • | The system voltage must be between 9.0-16.0 volts. |
Conditions for Setting the DTC
The motor control circuit current monitored by the MSM is determined to be shorted to ground or battery positive voltage or open.
Action Taken When the DTC Sets
| • | The MSM will disable the seat motor for which a current status DTC is set. |
| • | 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
The numbers below refer to the step numbers on the diagnostic table.
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Verify that the DTC is current or history by attempting to operate the seat motor for which the code is set.
-
Tests the motor control circuits for proper operation.
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 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information | ||||||
Does the seat adjuster motor operate through the full range of adjustment? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 | |||||||
Does the test lamp illuminate when the switch is activated and turn OFF when the switch is released? | Go to Step 5 | Go to Step 4 | |||||||
4 | Test and repair the adjuster motor control circuits for the following conditions:
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. 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 Wiring Repairs in Wiring Systems. 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 memory seat module (MSM). Refer to Circuit Testing and Wiring Repairs in Wiring Systems. 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 Replacement . Did you complete the replacement? | Go to Step 9 | -- | ||||||
8 | Replace the MSM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 9 | -- | ||||||
9 |
Does the DTC reset? | Go to Step 2 | System OK | ||||||
