Circuit Description
The driver and passenger seat heaters are controlled by the driver seat module. 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 driver seat module through individual low side drive control circuits. The heater element control circuits are pulse width modulated to ground by the driver seat module in order to control the seat temperatures by regulating the current flow through the heater elements.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC B2425 Driver Seat Heater Circuit |
| • | DTC B2430 Passenger Seat Heater Circuit |
Conditions for Running the DTC
The system voltage must be between 9-16 volts.
Conditions for Setting the DTC
The driver seat module determines by monitoring the heater element control circuits that a short to voltage, short to ground, or open condition exists.
Action Taken When the DTC Sets
| • | The heated seat with a current status DTC will be disabled. |
| • | Both heated seats may 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 | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: Driver 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 fault 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 voltage present on either of the heater element control circuits? | -- | Go to Step 7 | Go to Step 4 |
4 | Using a DMM test for continuity to ground at the heater element control circuit terminals in the driver seat module harness connector. Refer to Circuit Testing in Wiring Systems. Is continuity to ground present on either of the heater element control circuits? | -- | Go to Step 8 | Go to Step 5 |
5 |
Important: The seat heater elements must be at 20°C (68°F) when measuring resistance values. Using a DMM measure the resistance through the seat heater elements from the voltage supply circuit terminal to each of the control circuit terminals in the memory seat module harness connectors. Refer to Circuit Testing in Wiring Systems. Are the measurements within the specified values? | Cushion 2.0-2.5Ω Back 4.25-4.75Ω | Go to Step 10 | Go to Step 6 |
6 | Test the voltage supply and control circuits to the affected heater element for an open or high resistance. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 9 |
7 | Repair the voltage supply or control circuit to the affected heater element for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 13 | -- |
8 | Repair the voltage supply or control circuit to the affected heater element for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 13 | -- |
9 | Inspect for poor connections at the heater element 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 13 | Go to Step 11 |
10 | Inspect for poor connections at the driver seat module 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 13 | Go to Step 12 |
11 | Replace the affected seat heater element. Is the repair complete? | -- | Go to Step 13 | -- |
12 | Replace the driver seat module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming. Is the repair complete? | -- | Go to Step 13 | -- |
13 |
Does the DTC reset? | -- | Go to Step 3 | System OK |
