B1547

DTC B1547, B1770, or B1785

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 B1547 0B
- Seat Back Rotation Motor Circuit Current Above Threshold

DTC B1770 0B
- Seat Motor (Assembly Horizontally) Circuit Current Above Threshold

DTC B1785 0B
- Seat Motor (Recline) Circuit Current Above Threshold




Diagnostic Fault Information






Circuit/System Description

Battery positive voltage is supplied to the rear seat module (RSM) from the 30 A RSM fuse located in the left rear fuse block. When commanded, this voltage is used by the RSM to power the seat motors through there respective motor control circuits. During seat operation, the driven motor current is monitored through the motor control circuits by the RSM. When an overcurrent condition is detected, the RSM disables the seat motors in order to protect the internal RSM circuitry.


Conditions for Running the DTC

The RSM monitors for overcurrent only when the seat motors are active.


Conditions for Setting the DTC

The RSM will set this DTC when the current draw on an active motor exceeds a calibrated threshold.


Action Taken When the DTC Sets

* If the seat is moving when this condition occurs, the operation will be aborted.
* The RSM will not respond to all third row seat switch inputs.
* The RSM will set a history DTC.



Conditions for Clearing the DTC

* The RSM does not detect an overcurrent condition during seat movement.
* The history code will clear if the RSM does not detect an overcurrent for 100 ignition cycles.



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. Connect a test lamp between control circuits terminal 1 and terminal 2.
3. Ignition ON, 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 the control circuits for a short ground. If the circuits test normal, replace the RSM.

4. If all circuits test normal, test or replace the seat motor.



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