B1840

DTC B1735, B1740, B1745, B1750, B1755, B1760, B1815, B1820, B1830, B1835, B1840, B1845, B2085, or B2090

DTC Descriptors
DTC B1735 01
- Driver Seat Front Up Switch Circuit

DTC B1740 01
- Driver Seat Front Down Switch Circuit

DTC B1745 01
- Driver Seat Rear Up Switch Circuit

DTC B1750 01
- Driver Seat Rear Down Switch Circuit

DTC B1755 01
- Driver Seat Assembly Horizontal Forward Switch Circuit

DTC B1760 01
- Driver Seat Assembly Horizontal Rearward Switch Circuit

DTC B1815 01
- Driver Seat Recline Forward Switch Circuit

DTC B1820 01
- Driver Seat Recline Rearward Switch Circuit

DTC B1830 01
- Driver Seat Lumbar Forward Switch Circuit

DTC B1835 01
- Driver Seat Lumbar Rearward Switch Circuit

DTC B1840 01
- Driver Seat Lumbar Up Switch Circuit

DTC B1845 01
- Driver Seat Lumbar Down Switch Circuit

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview






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 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 power mode changes to OFF then back to ACC or RUN.
* The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.

Diagnostic Aids

* The scan tool may reference the Memory Seat Module (MSM) as the Driver Position Module.
* If one of the switch signal circuits is shorted to battery, multiple codes will set.

Circuit/System Verification

Ignition ON, observe the scan tool Driver Position Module, Seat 1 Inputs seat switch parameters, while pressing the seat directional switches. The reading should change between Inactive and Active.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate seat or lumbar adjuster switch.
2. Ignition ON, verify the scan tool seat or lumbar switch parameters are Inactive.

• If not Inactive, test the signal circuit that displays Active for a short to voltage. If the circuit tests normal, replace the MSM.

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

Component Testing

1. Ignition OFF, disconnect the harness connector at the appropriate seat or lumbar adjuster switch.
2. Test for infinite resistance between each seat direction signal terminal and the switch B+ terminal with the switch in the open position.

• If less than infinite resistance, replace the switch.

3. Test for less than 1 ohm of resistance between each seat direction signal terminal and the B+ terminal with the switch in the closed position.

• If greater than 1 ohm, replace the switch.

Repair Instructions

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

* Seat Switch Replacement - Power
* Lumbar Switch Replacement - Rear
* Programming and Relearning for memory seat module setup, and programming. Programming and Relearning