Circuit Description
The driver and passenger seat heaters are controlled by the driver seat module (DSM). Power is supplied to the driver seat cushion and back heater elements through individual voltage supply circuits. Power is supplied to the passenger seat cushion and back heater elements through a common voltage supply circuit. All of the driver and passenger seat heater elements are grounded by the DSM through individual low side drive control circuits. The heater element control circuits are pulse width modulated to ground by the DSM in order to control the seat temperatures by regulating the current flow through the heater elements.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B3941 Front Seat Heaters Circuit
Conditions for Running the DTC
The system voltage must be between 9-16 volts.
Conditions for Setting the DTC
The DSM determines that one of the seat heater element voltage supply circuits is shorted to ground.
Action Taken When the DTC Sets
| • | Both heated seats will be disabled. |
| • | When the fault is no longer present a history status DTC will be stored, and heated seat operation will be restored. |
Conditions for Clearing the DTC
| • | The DTC will be current for as long as the fault is present. |
| • | When the fault is no longer present the DTC will be a history status code. |
| • | The history DTC will be cleared after 100 error free ignition cycles, or by using the scan tool clearing DTCs feature. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Driver Seat Schematics , Passenger Seat Schematics Connector End View Reference: Power Seat Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 | Verify the condition is present. Does the system operate normally? | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 3 |
3 |
Is continuity to ground present on any of the heater element supply circuits? | Go to Step 4 | Go to Step 6 |
4 |
Did you find and correct the condition? | Go to Step 9 | Go to Step 5 |
5 | Inspect for poor connections at the seat heater element harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 7 |
6 | Inspect for poor connections at the DSM harness connectors. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 9 | Go to Step 8 |
7 | Replace the seat heater element. Refer to Driver Seat and Passenger Seat Back Cushion Heater Replacement or Driver Seat and Passenger Seat Cushion Heater Replacement . Did you complete the replacement? | Go to Step 9 | -- |
8 | Replace the DSM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Did you complete the replacement? | Go to Step 9 | -- |
9 |
Does the DTC reset? | Go to Step 2 | System OK |
