The rear seat heating elements are controlled by a common high current relay internal to the rear heated seat module (RHSM) and on the low side by
individual element control circuits. The RHSM connects the seat heater element supply voltage circuits to a common reference point. This reference
point is biased to approximately 2.5 V. Before the RHSM 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 RHSM 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 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.
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.
Action Taken When the DTC Sets
The heated seat function for both 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.
Reference Information
Schematic Reference
Heated/Cooled Seat Schematics ()
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Heated Seats Description and Operation (KA1) ()Heated Seats Description and Operation (KA6) ()
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Verification
Verify the type of vehicle and the heated seat system for which the DTC set.
If the DTC set in the rear heated seat module, refer to Circuit/System Testing below.
If the DTC set in a vehicle equipped with memory, refer to DTC B2508 or B2509 (w/o HP2 with memory).
If the DTC set in a hybrid vehicle without memory, refer to DTC B2508 or B2509 (HP2 w/o memory).
If the DTC set in a non-hybrid vehicle without memory, refer to DTC B2508 or B2509 (Dealer installed).
Circuit/System Testing
1. Ignition OFF, disconnect the X1 harness connector at the RHSM.
2. Test for infinite resistance between the control circuit terminal 3 and ground.
