B1548

DTC B1548, B1825, or B2375

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)provides an overview of each diagnostic category.



DTC Descriptors
DTC B1548 0A
- Seat Back Rotation Position Sensor Circuit

DTC B1825 0A
- Seat Recline Position Sensor Circuit

DTC B2375 0A
- Seat Assembly Horizontal Position Sensor Circuit




Diagnostic Fault Information






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 must not be present.
* Battery voltage must be between 9-16 volts.
* The seat adjuster motor must be active.



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, short to ground, or short to battery voltage in the position sensor signal circuit.
* An open in the position senor low reference circuit.
* An open in one of 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

Rear Seat Schematics (Rear Seat Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Power Seats System Description and Operation (Folding Seat) (Power Seats System Description and Operation (Folding Seat))Power Seats System Description and Operation (Front Seat) (Power Seats System Description and Operation (Front Seat))
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning)


Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate seat adjuster motor for which the DTC set.
2. Ignition OFF, test for less than 2 ohms of resistance between the low reference circuit terminal 3 and ground.

• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the RSM.

3. Ignition ON, test for 4.5-12 volts between the signal circuit terminal 4 and ground.

• 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.

4. Connect a test lamp between control circuits terminal 1 and terminal 2.
5. 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 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.

6. If all circuits test normal, test or replace the motor/position sensor.



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. The RSM must be calibrated before the folding seat system will operate. Refer to Power Folding Seat Calibration (Programming and Relearning) .



Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Rear Seat Number 2 Back Pivot Actuator Motor Replacement - Cushion (Rear Seat Number 2 Back Pivot Actuator Motor Replacement - Cushion)
* Rear Seat Number 2 Back Pivot Actuator Motor Replacement - Back Cushion (Rear Seat Number 2 Back Pivot Actuator Motor Replacement - Back Cushion)
* Rear Seat Number 2 Back Recliner Actuator Motor Replacement (Rear Seat Number 2 Back Recliner Actuator Motor Replacement)
* Control Module References (Programming and Relearning)for RSM replacement, setup, and programming