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 |
|---|---|---|---|---|
Left Rear Heated Seat Back Element Supply Voltage | B2508 02 | B1935 0D | B2508 01 | B1935 0E |
Left Rear Heated Seat Back Element Control | B2508 02 | B1935 0D | B2508 01 | B1935 0E |
Left Rear Heated Seat Back Temperature Sensor Signal | B2435 02 | B2435 05 | B2435 05 | B2345 13, B2345 42, B2345 4B |
Left Rear Heated Seat Back Temperature Sensor Low Reference | -- | B2435 05 | -- | B2345 13, B2345 42, B2345 4B |
Left Rear Heated Seat Cushion Element Supply Voltage | B2508 02 | B2425 0D | B2508 01 | B2425 0E |
Left Rear Heated Seat Cushion Element Control | B2508 02 | B2425 0D | B2508 01 | B2425 0E |
Left Rear Heated Seat Cushion Temperature Sensor Signal | B1925 02 | B1925 05 | B1925 05 | B2345 13, B2345 42, B2345 4B |
Left Rear Heated Seat Cushion Temperature Sensor Low Reference | -- | B1925 05 | -- | B2345 13, B2345 42, B2345 4B |
Right Rear Heated Seat Back Element Supply Voltage | B2508 02 | B2180 0D | B2508 01 | B2180 0E |
Right Rear Heated Seat Back Element Control | B2508 02 | B2180 0D | B2508 01 | B2180 0E |
Right Rear Heated Seat Back Temperature Sensor Signal | B2440 02 | B2440 05 | B2440 05 | B2345 13, B2345 42, B2345 4B |
Right Rear Heated Seat Back Temperature Sensor Low Reference | -- | B2440 05 | -- | B2345 13, B2345 42, B2345 4B |
Right Rear Heated Seat Cushion Element Supply Voltage | B2508 02 | B2430 0D | B2508 01 | B2430 0E |
Right Rear Heated Seat Cushion Element Control | B2508 02 | B2430 0D | B2508 01 | B2430 0E |
Right Rear Heated Seat Cushion Temperature Sensor Signal | B2170 02 | B2170 05 | B2170 05 | B2345 13, B2345 42, B2345 4B |
Right Rear Heated Seat Cushion Temperature Sensor Low Reference | -- | B2170 05 | -- | B2345 13, B2345 42, B2345 4B |
Circuit/System Description
The left and right rear heated seat heating elements are controlled by a common high current relay internal to the rear heated seat module (RHSM) and the low side by individual element control circuits. The RHSM 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 RHSM will allow heated seat operation, it checks to see if this reference voltage is shorted to ground or battery voltage. Once the module verifies that it is not closing to a shorted heating element, it allows heated seat operation. After which it continues to monitor for a shorted circuit.
Conditions for Running the DTC
The RHSM must be powered.
Conditions for Setting the DTC
B2508 01
Before the heated seats are activated, the RHSM detects a short to battery voltage on the seat heating element supply voltage circuit or control circuit.
B2508 02
Before the heated seats are activated, the RHSM detects a short to ground on the seat heating element supply voltage circuit or control circuit.
Action Taken When the DTC Sets
The heated seat function for the left and right rear passenger seats will be disabled.
Conditions for Clearing the DTC
| • | The current DTC will clear and set to history 3 seconds after the reference voltage returns to the normal operating range and the power mode changes to 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
Description and Operation
Rear Heated Seats Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disconnect the X1 harness connector at the RHSM.
- Test for infinite resistance between the control circuit terminal 3 and ground.
- Test for infinite resistance between the control circuit terminal 6 and ground.
- Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 3 and ground.
- Verify that a test lamp does not illuminate between the control circuit terminal 6 and ground.
- If all circuits test normal, replace the RHSM.
| ⇒ | If not the specified value, test the control circuits listed below for a short to ground. |
| • | Left rear seat cushion and back element terminal 3 |
| • | Left rear seat cushion element terminal 5 |
| • | Left rear seat back element terminal 1 |
| ⇒ | If not the specified value, test the control circuits listed below for a short to ground. |
| • | Right rear seat cushion and back element terminal 6 |
| • | Right rear seat cushion element terminal 2 |
| • | Right rear seat back element terminal 4 |
| ⇒ | If the test lamp illuminates, test the control circuits listed below for a short to voltage. |
| • | Left rear seat cushion and back element terminal 3 |
| • | Left rear seat cushion element terminal 5 |
| • | Left rear seat back element terminal 1 |
| ⇒ | If the test lamp illuminates, test the control circuits listed below for a short to voltage. |
| • | Right rear seat cushion and back element terminal 6 |
| • | Right rear seat cushion element terminal 2 |
| • | Right rear seat back element terminal 4 |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for RHSM replacement, setup, and programming |
