B2508

DTC B2508 or B2509

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

Left Seat Heater Relay Circuit Shorted to Battery or Open

Diagnostic Fault Information





Circuit/System Description

When the heated seat function is active, the heated seat module supplies battery voltage through the element supply voltage circuit to the seat cushion and seat back heater elements. The module then controls the seat temperature by providing a path to ground through the element control circuit. The module then monitors the current flow through the heating elements and the temperature sensor rate of change to verify correct operation.

Conditions for Running the DTC

The heated seat module is active, and none of the power diagnostic DTCs are current.

Conditions for Setting the DTC

B2508 02

The heated seat module detects a short to ground for 10 seconds on the seat heater element supply voltage circuit or the low reference circuit.

B2508 01

The heated seat module detects a short to battery voltage on the seat heater element supply voltage circuit or the low reference 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 3 seconds after the reference voltage returns to normal operating range.
* The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.

Circuit/System Testing

1. Ignition OFF, disconnect the C1 harness connector at the heated seat module.
2. Test for infinite resistance between the supply voltage circuit terminal 3 and ground.

• If less than infinite, test the element supply voltage circuit and control circuit for a short to ground.

3. Test for infinite resistance between the supply voltage circuit terminal 6 and ground.

• If less than infinite, test the element supply voltage circuit and control circuit 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 element supply voltage circuit and control circuit for a short to voltage.

5. Verify that a test lamp does not illuminate between the supply voltage circuit terminal 6 and ground.

• If the test lamp illuminates, test the element supply voltage circuit and 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.

* Seat Back Heater Element Replacement - Front (Impala) Seat Back Heater Element Replacement - Front (Monte Carlo)
* Seat Cushion Heater Element Replacement - Front (Impala) Seat Cushion Heater Element Replacement - Front (Monte Carlo)
* Programming and Relearning Programming and Relearning>