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 01: Seat Front Up Switch Circuit Short to BatteryDTC B1740 01: Seat Front Down Switch Circuit Short to Battery
DTC B1745 01: Seat Rear Up Switch Circuit Short to Battery
DTC B1750 01: Seat Rear Down Switch Circuit Short to Battery
DTC B1755 01: Seat Assembly Forward Switch Circuit Short to Battery
DTC B1760 01: Seat Assembly Rearward Switch Circuit Short to Battery
DTC B1815 01: Seat Recline Forward Switch Circuit Short to Battery
DTC B1820 01: Seat Recline Rearward Switch Circuit Short to Battery
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Front Vertical Up Switch Signal | 3 | 1 | B1735 01, B1740 01, B1745 01, B1750 01, B1755 01, B1760 01, B1815 01, B1820 01 | -- |
Front Vertical Down Switch Signal | 3 | 1 | B1735 01, B1740 01, B1745 01, B1750 01, B1755 01, B1760 01, B1815 01, B1820 01 | -- |
Rear Vertical Up Switch Signal | 3 | 1 | B1735 01, B1740 01, B1745 01, B1750 01, B1755 01, B1760 01, B1815 01, B1820 01 | -- |
Rear Vertical Down Switch Signal | 3 | 1 | B1735 01, B1740 01, B1745 01, B1750 01, B1755 01, B1760 01, B1815 01, B1820 01 | -- |
Horizontal Forward Switch Signal | 3 | 1 | B1735 01, B1740 01, B1745 01, B1750 01, B1755 01, B1760 01, B1815 01, B1820 01 | -- |
Horizontal Rearward Switch Signal | 3 | 1 | B1735 01, B1740 01, B1745 01, B1750 01, B1755 01, B1760 01, B1815 01, B1820 01 | -- |
Recline Forward Switch Signal | 3 | 1 | B1735 01, B1740 01, B1745 01, B1750 01, B1755 01, B1760 01, B1815 01, B1820 01 | -- |
Recline Rearward Switch Signal | 3 | 1 | B1735 01, B1740 01, B1745 01, B1750 01, B1755 01, B1760 01, B1815 01, B1820 01 | -- |
Lumbar Forward Switch Signal | 3 | 2 | 2 | -- |
Lumbar Rearward Switch Signal | 3 | 2 | 2 | -- |
1. Power Seat Inoperative with Memory-A45 2. Lumbar Support Inoperative with Memory-A45 3. Scan Tool Does Not Communicate with Low Speed GMLAN Device | ||||
Circuit/System 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 and lumbar motors to move in response to the switch signals.
Conditions for Running the DTC
The MSM must be powered.
Conditions for Setting the DTC
| • | If a seat switch circuit is active in one direction and the switch for the opposite direction is pressed, this DTC will set. |
| • | 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 and set the code to history, 3 seconds after the fault is no longer present and the ignition is cycled OFF then back to ACC or RUN. |
| • | The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred. |
Diagnostic Aids
If one of the switch signal circuits is shorted to battery, multiple codes will set.
Reference Information
Schematic Reference
Connector End View Reference
Power Seat Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Ignition ON, observe the scan tool seat switch parameters while pressing the related seat adjuster switches. The reading should change between Inactive and Active.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the seat adjuster switch.
- 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 Upward Switch |
| • | Front Vertical Downward Switch |
| • | Rear Vertical Upward Switch |
| • | Rear Vertical Downward Switch |
| • | Horizontal Forward Switch |
| • | Horizontal Rearward Switch |
| • | Recline Forward Switch |
| • | Recline Rearward Switch |
| ⇒ | If not Inactive, test the signal circuit that displays Active for a short to voltage. If the circuit tests normal, replace the MSM. |
Component Testing
Seat Adjuster Switch
- Ignition OFF, disconnect the harness connector at the seat adjuster switch.
- Test for infinite resistance between each signal terminal (A, B, D, E, and J-M) and the B+ terminal F with the switch in the open position.
- Test for less than 1 ohm of resistance between each signal terminal (A, B, D, E, and J-M) and the B+ terminal F with the switch in the closed position.
| ⇒ | If less than the specified value, replace the seat adjuster switch. |
| ⇒ | 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 memory seat module replacement, setup, and programming |
