DTC B1548, B1825, or B2375 Rear Seat Module
Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC B1548 0A: Seat Back Rotation Position Sensor CircuitDTC B1825 0A: Seat Recline Position Sensor Circuit
DTC B2375 0A: Seat Assembly Horizontal Position Sensor Circuit
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Folding Seat Horizontal Position Sensor Signal | B2375 0A | B2375 0A | B2375 0A | -- |
Folding Seat Recline Position Sensor Signal | B1825 0A | B1825 0A | B1825 0A | -- |
Folding Seat Rotation Position Sensor Signal | B1548 0A | B1548 0A | B1548 0A | -- |
Folding Seat Horizontal Motor Forward Control | B1770 0B | B2375 0A or 1 | -- | -- |
Folding Seat Horizontal Motor Rearward Control | B1770 0B | B2375 0A or 1 | -- | -- |
Folding Seat Recline Motor Forward Control | B1785 0B | B1825 0A or 1 | -- | -- |
Folding Seat Recline Motor Rearward Control | B1785 0B | B1825 0A or 1 | -- | -- |
Folding Seat Rotation Motor Forward Control | B1547 0B | B1548 0A or 1 | -- | -- |
Folding Seat Rotation Motor Rearward Control | B1547 0B | B1548 0A or 1 | -- | -- |
Low Reference | -- | B1548 0A, B1825 0A, B2375 0A | -- | -- |
1. Rear folding seat inoperative | ||||
Circuit/System 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.
Conditions for Running the DTC
| • | DTC B1327 - Device Power Circuit 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.
Reference Information
Schematic Reference
Connector End View Reference
Power Seat Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the appropriate seat adjuster motor for which the DTC set.
- Ignition OFF, test for less than 2 ohms of resistance between the low reference circuit terminal 3 and ground.
- Ignition ON, test for 4.5-12 volts between the signal circuit terminal 4 and ground.
- Connect a test lamp between the control circuits terminal 1 and terminal 2.
- Command the appropriate motor to the FORWARD and REARWARD directions with a scan tool. The test lamp should momentarily turn ON when commanding the FORWARD and REARWARD states.
- If all circuits test normal, test or replace the motor/position sensor.
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the RSM. |
| ⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the RSM. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the RSM. |
| ⇒ | If the test lamp remains OFF during either of the commands, test for a short to ground or an open/high resistance on either control circuit. If the circuits test normal, replace the RSM. |
Repair Instructions
Important: After performing this diagnostic test and 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 .
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for rear seat module replacement, setup, and programming |
