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 B1831 00: Lumbar Forward Switch StuckDTC B1836 00: Lumbar Rearward Switch Stuck
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Lumbar Forward Switch Signal | 1 | 1 | B1831 00 | -- |
Lumbar Rearward Switch Signal | 1 | 1 | B1836 00 | -- |
1. Lumbar Support Inoperative | ||||
Circuit/System Description
When the lumbar switches are pressed, they send 12 V signal through the switch signal circuit to the memory seat module (MSM). The MSM interprets the signal and commands the lumbar motor 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 lumbar 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. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Memory Seats 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 MSM Lumbar Switch parameter while pressing and releasing the lumbar switch in both directions. The reading should change between Inactive and Active
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the lumbar switch.
- Ignition ON, verify the scan tool Lumbar Switch parameter is Inactive.
- If all circuits test normal, test or replace the lumbar 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. |
| • | Lumbar forward switch signal terminal 2 |
| • | Lumbar rearward switch signal terminal 4 |
Component Testing
Lumbar Switch
- Ignition OFF, disconnect the harness connector at the lumbar switch.
- Test for infinite resistance between the 12 V reference terminal 3 and each signal terminal listed below and with the switch in the open position.
- Test for less than 1 Ω between the 12 V reference terminal 3 and each signal terminal listed below and with the appropriate switch in the closed position.
| • | Lumbar forward switch signal terminal 2 |
| • | Lumbar rearward switch signal terminal 4 |
| ⇒ | If not the specified value, replace the lumbar switch. |
| • | Lumbar forward switch signal terminal 2 |
| • | Lumbar rearward switch signal terminal 4 |
| ⇒ | If greater than the specified range, replace the lumbar switch. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for MSM replacement, setup, and programming |
