Circuit Description
The rear seat module (RSM) monitors the position the rear folding seat motors by using hall effect position sensors which are an internal part of each motor. The RSM supplies each sensor with a 12-volt reference signal circuit and a low reference circuit. During seat operation, while the motor is active, each sensor provides the RSM with a single feedback pulse through the respective signal circuits for every rotation of the motor shaft. The RSM counts the feedback pulses from each sensor to determine seat position and end of travel limits for each of the seat motors.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC B1548 Seat Back Rotation Position Sensor Circuit |
| • | DTC B1825 Seat Recline Position Sensor Circuit |
| • | DTC B2375 Seat Assembly Horizontal Position Sensor Circuit |
Conditions for Running the DTC
| • | DTC B1327 - Battery Voltage Low is not current. |
| • | The seat adjuster motor must be active. |
| • | The RSM does not detect a stall condition on the motor being tested. |
Conditions for Setting the DTC
The RSM does not detect position sensor movement or pulse signals while the adjuster motor is active. The following conditions will set this DTC:
| • | An open, a short to ground, or a short to battery voltage in the position sensor signal circuit. |
| • | An open in the position senor low reference circuit. |
| • | An open in one the seat motor control circuits. |
Action Taken When the DTC Sets
| • | Current and history codes are set. |
| • | If the seat is moving when this condition occurs, the operation will be aborted. |
| • | While this condition exists all switch inputs will be ignored. |
Conditions for Clearing the DTC
The RSM will clear the current DTC whenever a stow switch is activated and the RSM receives pulse signals from the position sensor while the motor is active.
Test Description
The number below refers to the step number on the diagnostic table.
-
This step determines if the fault is in the seat motor or motor control circuits, or, the position sensor or sensor circuits.
-
This step verifies the repair.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: Rear 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 |
2 |
Did the rear seat module (RSM) set a current position sensor DTC? | -- | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems |
Does the motor momentarily move a short distance then stop? | -- | Go to Step 4 | Go to Step 6 | |
4 |
Does the voltage measure within the specified range? | 4.50-12 V | Go to Step 5 | Go to Step 7 |
5 | Measure the voltage between the signal circuit of the sensor connector and the low reference circuit of the sensor connector. Does the voltage measure within the specified range? | 4.50-12 V | Go to Step 8 | Go to Step 9 |
6 |
Does the test lamp momentarily illuminate? | -- | Go to Step 11 | Go to Step 10 |
7 | Test the signal circuit of the position sensor for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
8 |
Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 11 |
9 | Test the low reference circuit of the position sensor for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
10 | Test the motor control circuits of the inoperative seat motor for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
11 | Inspect for poor connections at the harness connector of the seat motor/position sensor assembly. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 13 |
12 | Inspect for poor connections at the harness connector of the RSM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 |
13 | Replace the appropriate motor/position sensor assembly. Refer to Rear Seat Number 2 Back Pivot Actuator Motor Replacement - Cushion , Rear Seat Number 2 Back Pivot Actuator Motor Replacement - Back Cushion , or Rear Seat Number 2 Back Recliner Actuator Motor Replacement . Did you complete the replacement? | -- | Go to Step 15 | -- |
14 | Replace the RSM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | -- | Go to Step 15 | -- |
|
Important: After performing this diagnostic test and the electrical or component repairs have been completed, the folding seat will be in an unknown state and out of calibration with the RSM. Therefore, the RSM must be calibrated before the folding seat system will operate. Refer to Power Folding Seat Calibration .
Does the DTC reset? | -- | Go to Step 3 | System OK | |
