Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC B2508 01: Seat Heater Relay Circuit Short to BatteryDTC B2508 02: Seat Heater Relay Circuit Short to Ground
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Driver Heated Seat Element Supply Voltage | B2508 02 | B2425 0C, B2425 0D | B2508 01 | -- |
Driver Heated Seat Element Control | B2508 02 | B2425 0C, B2425 0D | B2508 01 | -- |
Driver Heated Seat Temperature Sensor Signal | B1925 02 | B1925 05, B2425 04, B2425 1F | B1925 05, B2425 04, B2425 1F | -- |
Driver Heated Seat Temperature Sensor Low Reference | -- | B1925 05, B2425 04, B2425 1F | -- | -- |
Passenger Heated Seat Element Supply Voltage | B2508 02 | B2430 0C, B2430 0D | B2508 01 | -- |
Passenger Heated Seat Element Control | B2508 02 | B2430 0C, B2430 0D | B2508 01 | -- |
Passenger Heated Seat Temperature Sensor Signal | B2170 02 | B2170 05, B2430 04, B2430 1F | B2170 05, B2430 04, B2430 1F | -- |
Passenger Heated Seat Temperature Sensor Low Reference | -- | B2170 05, B2430 04, B2430 1F | -- | -- |
Circuit/System Description
The driver and passenger seat heating elements are controlled by a common high current relay internal to the heated seat module and by individual low side element control circuits. The heated seat module connects the heated seat heater element supply voltage circuits for both seats to a common reference point. This reference point is biased to approximately 2.0 volts. Before the heated seat module will allow heated seat operation, it checks to see if this reference voltage is shorted to ground or voltage. Once the module verifies that it is not closing to a shorted heating element, it allows for heated seat operation. The module will then continue to monitor the heating elements for a shorted circuit.
Conditions for Running the DTC
The heated seat module must be powered.
Conditions for Setting the DTC
B2508 01
The heated seat module detects a short to voltage on the heater element supply voltage circuit or the control circuit.
B2508 02
The heated seat module detects a short to ground on the heater element supply voltage circuit or the control circuit.
Action Taken When the DTC Sets
The heated seat function for both the driver and passenger seats will be disabled.
Conditions for Clearing the DTC
| • | The current DTC will clear and set the code to history 3 seconds after the reference voltage returns to the normal operating range and the ignition is cycled OFF then back to ACC or RUN. |
| • | The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred. |
Reference Information
Schematic Reference
Connector End View Reference
Power Seat Connector End Views
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
- Ignition OFF, disconnect the C1 harness connector at the heated seat module.
- Test for infinite resistance between the supply voltage circuit terminal 3 and ground.
- Test for infinite resistance between the supply voltage circuit terminal 6 and ground.
- Ignition ON, verify that a test lamp does not illuminate between the supply voltage circuit terminal 3 and ground.
- Verify that a test lamp does not illuminate between the supply voltage circuit terminal 6 and ground.
- If all circuits test normal, replace the heated seat module.
| ⇒ | If less than the specified range, test the element supply voltage circuit and control circuit for a short to ground. |
| ⇒ | If less than the specified range, test the element supply voltage circuit and control circuit for a short to ground. |
| ⇒ | If the test lamp illuminates, test the element supply voltage circuit and control circuit for a short to voltage. |
| ⇒ | If the test lamp illuminates, test the element supply voltage circuit and control circuit for a short to voltage. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for heated seat control module replacement, programming and setup. |
