Circuit Description
The heated seat switch and a heat sensor located in the seat cushion are connected in series and provide a single input to the driver seat module (DSM). A 5-volt reference voltage is supplied to the heated seat switch from the driver seat module. When the heated seat switch is in the high or low positions voltage is supplied through one of the internal resistors to the switch signal circuit. The heated seat switch signal circuit is grounded through the seat heat sensor which is a temperature sensitive variable resistor. The heated seat switch signal circuit input to the driver seat module is spliced from the circuit between the switch and the heat sensor, where the voltage level is determined by the resistance of both components.
DTC Descriptors
This diagnostic procedure supports the following DTCs:
| • | DTC B2435 Driver Seat Back Heater Sensor Circuit |
| • | DTC B2440 Passenger Seat Back Heater Sensor Circuit |
Conditions for Running the DTC
Battery voltage to the seat module must be within 8-17 volts.
Conditions for Setting the DTC
| • | The heated seat sensor signal circuit voltage to the seat module is greater than 5 volts for 30 seconds or more. |
| • | The heated seat sensor signal circuit input to the seat module indicates that the desired seat temperature has not been reached within 34 minutes after activation. |
Action Taken When the DTC Sets
The heated seat with a current status DTC will be disabled.
Conditions for Clearing the DTC
| • | The DTC will be stored as a history code when the fault is no longer present. |
| • | A history DTC will be cleared after completing 100 consecutive ignition cycles, or by using the scan tool clearing DTCs feature. |
Diagnostic Aids
If the DTC is only found in history and the heated seat is operating normally, the fault may be intermittent. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Step | Action | Values | 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 |
Does the scan tool indicate that the seat heat sensor value is greater than the specified value? | 4 V | Go to Step 4 | Go to Step 3 |
3 | Continue to operate the heated seat in the low mode for several minutes. Is the seat heat sensor value reducing as the heated seat operates? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Heated Seat Inoperative |
4 |
Is the voltage value greater than the specified value? | 5 V | Go to Step 6 | Go to Step 5 |
5 | Test the heated seat switch high/low signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 7 |
6 | Repair the heated seat switch 5-volt supply circuit for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Is the repair complete? | -- | Go to Step 9 | -- |
7 | Inspect for poor connections at the driver seat module (DSM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 8 |
8 | Replace the DSM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming . Is the repair complete? | -- | Go to Step 9 | -- |
9 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
