B2509

DTC B2508 or B2509

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptors
DTC B2508 01
- Left Seat Cushion Heater Sensor Circuit Shorted to Ground

DTC B2508 02
- Left Seat Cushion Heater Sensor Circuit Shorted to Battery or Open




Diagnostic Fault Information






Circuit/System Description

The rear heated seat heating elements are controlled by a common high current relay internal to the rear heated seat module and individual low side element control circuits for each heating element. Before the heated seat module will allow heated seat operation, it checks to see if the heating element supply voltage circuits and control circuits are 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 will continue to monitor for a shorted circuit.


Conditions for Running the DTC

The rear heated seat module must be powered.


Conditions for Setting the DTC

B2508 01

Before the heated seats are activated, the heated seat module 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 heated seat module 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 both 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

Heated/Cooled Seat Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Rear Heated Seats Description and Operation (Rear Heated Seats Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Programming and Relearning (Programming and Relearning) for Scan Tool Information


Circuit/System Testing

1. Ignition OFF, disconnect the X1 harness connector at the rear heated seat module.
2. Test for infinite resistance between the left seat heating element supply voltage circuit terminal 3 and ground.

• If less than the specified range, test the supply voltage circuit and the seat cushion and seat back heating element control circuits for a short to ground.

3. Test for infinite resistance between the right seat heating element supply voltage circuit terminal 6 and ground.

• If less than the specified range, test the supply voltage circuit and the seat cushion and seat back heating element control circuits for a short to ground.

4. Ignition ON, verify that a test lamp does not illuminate between the supply voltage circuit terminal 3 and ground.

• If the test lamp illuminates, test the supply voltage circuit and the seat cushion and seat back heating element control circuits for a short to voltage.

5. Ignition ON, verify that a test lamp does not illuminate between the supply voltage circuit terminal 6 and ground.

• If the test lamp illuminates, test the supply voltage circuit and the seat cushion and seat back heating element control circuits for a short to voltage.

6. If all circuits test normal, replace the heated seat module.



Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Rear Seat Cushion Heater Replacement (Rear Seat Cushion Heater Replacement)
* Rear Seat Back Cushion Heater Replacement (Rear Seat Back Cushion Heater Replacement)
* Programming and Relearning (Programming and Relearning) for the rear heated seat module replacement, setup, and programming