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
This diagnostic procedure supports the following DTCs:
DTC B1735 00: Front Vertical Up Switch StuckDTC B1740 00: Front Vertical Down Switch Stuck
DTC B1745 00: Rear Vertical Up Switch Stuck
DTC B1750 00: Rear Vertical Down Switch Stuck
DTC B1755 00: Horizontal Forward Switch Stuck
DTC B1760 00: Horizontal Back Switch Stuck
DTC B1815 00: Recline Up Switch Stuck
DTC B1820 00: Recline Down Switch Stuck
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Front Vertical Up Switch Signal | 2 | 1 | B1735 00, B1740 00, B1745 00, B1750 00, B1755 00, B1760 00, B1815 00, B1820 00 | -- |
Front Vertical Down Switch Signal | 2 | 1 | B1735 00, B1740 00, B1745 00, B1750 00, B1755 00, B1760 00, B1815 00, B1820 00 | -- |
Rear Vertical Up Switch Signal | 2 | 1 | B1735 00, B1740 00, B1745 00, B1750 00, B1755 00, B1760 00, B1815 00, B1820 00 | -- |
Rear Vertical Down Switch Signal | 2 | 1 | B1735 00, B1740 00, B1745 00, B1750 00, B1755 00, B1760 00, B1815 00, B1820 00 | -- |
Horizontal Forward Switch Signal | 2 | 1 | B1735 00, B1740 00, B1745 00, B1750 00, B1755 00, B1760 00, B1815 00, B1820 00 | -- |
Horizontal Rearward Switch Signal | 2 | 1 | B1735 00, B1740 00, B1745 00, B1750 00, B1755 00, B1760 00, B1815 00, B1820 00 | -- |
Recline Forward Switch Signal | 2 | 1 | B1735 00, B1740 00, B1745 00, B1750 00, B1755 00, B1760 00, B1815 00, B1820 00 | -- |
Recline Rearward Switch Signal | 2 | 1 | B1735 00, B1740 00, B1745 00, B1750 00, B1755 00, B1760 00, B1815 00, B1820 00 | -- |
1. Power seat inoperative 2. Scan Tool Does Not Communicate with Low Speed GMLAN Device | ||||
Circuit Description
When the power seat switches are pressed, they send a 12 volt signal through the switch signal circuits 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
The MSM must be powered and cannot have DTC B1327 Battery Positive Low as an active DTC for this DTC to set.
Conditions for Setting the DTC
| • | If a seat switch circuit continues to be active for 30 seconds after a motor controlled by that switch reaches the end of its travel, the switch will be considered shorted and the MSM will set the DTC. |
| • | A short to voltage on a switch signal circuit. |
Action Taken When the DTC Sets
| • | A motor output driven in response to a switch considered failed, is deactivated for both directions. |
| • | All memory recall commands are ignored. |
| • | The MSM will respond to any other switch signal that has not set a DTC. |
Conditions for Clearing the DTC
| • | The current DTC will clear when the switch circuit setting the DTC is no longer active. |
| • | The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, observe the scan tool Memory Seat Module seat switch parameters while pressing the appropriate seat directional switches. The reading should change between Inactive and Active.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the 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 seat adjuster switch.
| • | Front Vertical Switch |
| • | Rear Vertical Switch |
| • | Horizontal Switch |
| • | Recline Switch |
| ⇒ | If not the specified value, test the appropriate signal circuit listed below for a short to voltage. If the circuit tests normal, replace the MSM. |
| • | Front vertical upward switch terminal 10 |
| • | Front vertical downward switch terminal 7 |
| • | Rear vertical upward switch terminal 9 |
| • | Rear vertical downward switch terminal 8 |
| • | Horizontal forward switch terminal 3 |
| • | Horizontal rearward switch terminal 6 |
| • | Recline forward switch terminal 2 |
| • | Recline rearward switch terminal 4 |
Component Testing
- Ignition OFF, disconnect the harness connector at the seat adjuster switch.
- Test for infinite resistance between the B+ terminal 5 and each signal terminal listed below with the switch in the open position.
- Test for less than 1 Ω between the B+ terminal 5 and each signal terminal listed below with the appropriate switch in the closed position.
| • | Front vertical upward switch terminal 10 |
| • | Front vertical downward switch terminal 7 |
| • | Rear vertical upward switch terminal 9 |
| • | Rear vertical downward switch terminal 8 |
| • | Horizontal forward switch terminal 3 |
| • | Horizontal rearward switch terminal 6 |
| • | Recline forward switch terminal 2 |
| • | Recline rearward switch terminal 4 |
| ⇒ | If not the specified value, replace the seat adjuster switch. |
| • | Front vertical upward switch terminal 10 |
| • | Front vertical downward switch terminal 7 |
| • | Rear vertical upward switch terminal 9 |
| • | Rear vertical downward switch terminal 8 |
| • | Horizontal forward switch terminal 3 |
| • | Horizontal rearward switch terminal 6 |
| • | Recline forward switch terminal 2 |
| • | Recline rearward switch terminal 4 |
| ⇒ | 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 |
