B2508 (Rear Seat)

DTC B2508 or B2509 (Rear Seat)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* 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 Shorted to Battery or Open

DTC B2508 02
- Seat Heater Relay Circuit Shorted to Ground

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 on the low side by individual element control circuits. 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.

Conditions for Running the DTC

The rear heated seat module must be powered.

Conditions for Setting the DTC

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.

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.

Action Taken When the DTC Sets

The heated seat function for both of the rear passenger seats will be disabled.

Conditions for Clearing the DTC

* The current DTC clears when the malfunction is no longer present 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.

Circuit/System Testing

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

^ If less than infinite resistance, test the supply voltage circuit and the seat cushion heating element control circuit for a short to ground.

3. 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 heating element control circuit for a short to voltage.

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

^ If less than infinite resistance, test the supply voltage circuit and the seat cushion heating element control circuit for a short to ground.

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 heating element control circuit for a short to voltage.

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

Repair Instructions

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

* Rear Seat Cushion Heater Replacement