B1820

DTC B1735, B1740, B1745, B1750, B1755, B1760, B1815, or B1820

Circuit Description

When the power seat switches are pressed they send a 12-volt signal to the memory seat module (MSM). The MSM then commands the driver seat to move in response to the switch inputs.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

* DTC B1735 Seat Front Up Switch Circuit
* DTC B1740 Seat Front Down Switch Circuit
* DTC B1745 Seat Rear Up Switch
* DTC B1750 Seat Rear Down Switch Circuit
* DTC B1755 Seat Assembly Horizontal Forward Switch Circuit
* DTC B1760 Seat Assembly Horizontal Rearward Switch Circuit
* DTC B1815 Seat Recline Forward Switch Circuit
* DTC B1820 Seat Recline Rearward Switch Circuit

Conditions for Running the DTC

The MSM must be powered and cannot have B1327 - Battery Voltage Low as an active DTC for this DTC to set.

Conditions for Setting the DTC

* If a seat switch 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 a switch DTC.
* If a position sensor DTC is current and the associated switch is active for 30 continuous seconds, the switch will be considered shorted and the MSM will set a switch DTC.

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 command are ignored.
* The MSM will respond to any other switch signal that has not set a DTC.

Conditions for Clearing the DTC

The DTC automatically clears when the switch circuit setting the DTC is no longer active.

Test Description

Step 1 - Step 10:

The numbers below refer to the step numbers on the diagnostic table.
2. Checks the existing state of the driver's seat switch by using the current state of the seat switch parameter. If all of the seat switch parameters display active, possibly one of the seat switch signal circuits is shorted to voltage.
4. When the seat switch is disconnected, this step determines if the seat switch contacts are stuck closed, or if one of the switch signal circuits is possibly shorted to battery voltage.