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 B1735: Driver Seat Front Up Switch CircuitDTC 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
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
MSM B+ Terminal B11 X2 | B1420 | B1420 | -- | -- |
MSM B+ Terminal A X1 | 2 | 2 | -- | -- |
Seat Adjuster Switch B+ | B1420 | 1 | -- | -- |
Power Seat Front Vertical Up Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760 | -- |
Power Seat Front Vertical Down Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760 | -- |
Power Seat Horizontal Rearward Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760 | -- |
Power Seat Horizontal Forward Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760 | -- |
Power Seat Rear Vertical Up Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760 | -- |
Power Seat Rear Vertical Down Switch Signal | B1420 | 1 | B1735, B1740, B1745, B1750, B1755, B1760 | -- |
1. Power seat inoperative 2. The scan tool does not communicate with the memory seat module | ||||
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 pressed, battery voltage is applied through the switch contacts and the appropriate switch signal circuit to the memory seat module (MSM). The MSM then commands the driver seat motors to move in response to the switch signals.
Conditions for Running the DTC
| • | DTC B1327 must not be present. |
| • | Battery voltage must be between 9-16 volts. |
Conditions for Setting the DTC
B1735, B1740, B1745, B1750, B1755, or B1760
| • | 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. |
| • | The history DTC will clear once 50 consecutive fault-free ignition cycles have occurred. |
Diagnostic Aids
The memory seat module is also referred to as the Driver Position Module in certain scan tool menus.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Memory Seats Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Ignition ON, observe all scan tool Driver Position Module seat switch parameters while pressing and releasing each seat directional switch. The readings should change between Inactive and Active.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the driver seat adjuster switch.
- Ignition ON, verify the scan tool seat switch parameters listed below are Inactive:
- If all circuits test normal, test or replace the driver seat adjuster switch.
| • | Front Vertical Upward Switch |
| • | Front Vertical Downward Switch |
| • | Rear Vertical Upward Switch |
| • | Rear Vertical Downward Switch |
| • | Horizontal Forward Switch |
| • | Horizontal Rearward Switch |
| ⇒ | If not the specified value, test the appropriate signal circuit terminal listed below for a short to voltage. If the circuit tests normal, replace the MSM. |
| • | Front vertical upward switch terminal B |
| • | Front vertical downward switch terminal D |
| • | Rear vertical upward switch terminal A |
| • | Rear vertical downward switch terminal G |
| • | Horizontal forward switch terminal C |
| • | Horizontal rearward switch terminal F |
Component Testing
Seat Adjuster Switch
- Ignition OFF, disconnect the harness connector at the seat adjuster switch.
- Test for infinite resistance between the B+ terminal E and each seat direction signal terminal listed below with the switch in the open position:
- Test for less than 1 Ω between the B+ terminal E and each seat direction signal terminal listed below with the appropriate switch in the closed position:
| • | Front vertical upward switch terminal B |
| • | Front vertical downward switch terminal D |
| • | Rear vertical upward switch terminal A |
| • | Rear vertical downward switch terminal G |
| • | Horizontal forward switch terminal C |
| • | Horizontal rearward switch terminal F |
| ⇒ | If not the specified value, replace the seat adjuster switch. |
| • | Front vertical upward switch terminal B |
| • | Front vertical downward switch terminal D |
| • | Rear vertical upward switch terminal A |
| • | Rear vertical downward switch terminal G |
| • | Horizontal forward switch terminal C |
| • | Horizontal rearward switch terminal F |
| ⇒ | If greater than the specified range, replace the seat adjuster switch. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for MSM replacement, setup, and programming |
