B1755

DTC B1735, B1740, B1745, B1750, B1755, B1760, B1815, or B1820

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 B1735
- Driver Seat Front Up Switch Circuit

DTC B1740
- Driver Seat Front Down Switch Circuit

DTC B1745
- Driver Seat Rear Up Switch Circuit

DTC B1750
- Driver Seat Rear Down Switch Circuit

DTC B1755
- Driver Seat Assembly Horizontal Forward Switch Circuit

DTC B1760
- Driver Seat Assembly Horizontal Rearward Switch Circuit

DTC B1815
- Driver Seat Recline Forward Switch Circuit

DTC B1820
- Driver Seat Recline Rearward Switch Circuit




Diagnostic Fault Information






Circuit/System Description

Battery positive voltage is supplied at all times to the seat adjuster switch from the TELE SWITCH/MSM fuse located in the body control module (BCM) fuse block. When a seat adjustment switch is operated, battery voltage is applied through the switch contacts to the appropriate switch signal circuit to the memory seat module (MSM) input to ground. The MSM responds to the input from the adjuster switch by commanding the selected seat motor to move in response to the switch signal.


Conditions for Running the DTC

* DTC B1327 must not be present.
* Battery voltage must be between 9-16 volts.



Conditions for Setting the DTC

* The MSM will set these DTCs when a short to voltage is detected on a switch signal circuit.
* The MSM will set these DTCs if a seat switch circuit is active in one direction and a switch for the opposite direction is activated.
* The MSM will set these DTCs if a seat adjuster switch is active for 30 seconds after a motor has reached the end of its travel.



Actions Taken When the DTC Sets

* The motor associated with the inoperative switch adjuster signal circuit will be disabled for both directions.
* The memory seat functions for the seat will be disabled.
* The MSM will respond to any other switch adjuster signal that has not set a DTC.



Conditions for Clearing the DTCs

* The condition responsible for setting the DTC no longer exists.
* A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.



Diagnostic Aids

The memory seat module (MSM) is also referred to as the driver position module (DPM) in certain scan tool menus.


Reference Information
Schematic Reference

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

Component Connector End Views (Connector Views)
Description and Operation

Memory Seats Description and Operation (Memory Seats Description and Operation)
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 Verification

Ignition ON, observe the scan tool seat switch parameters located in the driver position module data display menu while activating each switch. The reading should change between ACTIVE and INACTIVE as each switch is activated.


Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the driver seat adjuster switch.
2. Ignition ON, verify the scan tool seat switch parameters display INACTIVE for all switches.

• If the scan tool displays ACTIVE, test the appropriate switch signal circuit for a short to voltage. If the circuit tests normal, replace the MSM.

3. If all circuits test normal, test or replace the driver seat adjuster switch.



Repair Instructions

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

* Driver Seat Adjuster and Recliner Switch Replacement (Driver Seat Adjuster and Recliner Switch Replacement)
* Control Module References (Programming and Relearning) for MSM replacement, setup, and programming