With Memory A45
DTC B242A (With Memory A45)
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC B242A 01
- Seat Heaters Common Circuit Short to Battery
DTC B242A 02
- Seat Heaters Common Circuit Short to Ground
Diagnostic Fault Information
Circuit/System Description
The seat memory control module controls seat heating operation for both the driver and front passenger seats. The heating elements are controlled through individual high side and low side control circuits. The low side control circuits for both seats are connected to a common reference point internal to the module. This reference point is biased to approximately 2.5 V. Before the seat heating control module will allow heated seat operation, it checks to see if this biased voltage is shorted to ground or voltage. Once the module verifies that it is not closing to a shorted heating element, it allows for heated seat operation. The module will then continue to monitor the heating elements for a shorted circuit.
Conditions for Running the DTC
* DTC B1325 must not be present.
* The seat memory control module must be powered.
Conditions for Setting the DTC
B242A 01
The seat memory control module detects a short to voltage on the heater element control circuits.
B242A 02
The seat memory control module detects a short to ground on the heater element control circuits.
Action Taken When the DTC Sets
The heated seat function for both seats will be disabled.
Conditions for Clearing the DTC
* The current DTC will clear and set a history code 3 seconds after the reference voltage returns to normal operating range and the ignition is cycled OFF then back to ACC or RUN.
* The history DTC will clear after 40 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 Sunshade - Left (DH6)
Description and Operation
Heated Seats Description and Operation Description and Operation
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the X4 harness connector at the K40 seat memory control module, ignition ON.
2. Verify a test lamp illuminates between the B+ circuit terminal 5 and ground.
• If the test lamp does not illuminate
1. Ignition OFF.
2. Test for less than 2 ohms in the B+ circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, verify the fuse is not open and there is voltage at the circuit breaker.
• If the test lamp illuminates
3. Ignition OFF, connect the X4 harness connector at the K40 seat memory control module and disconnect the X3 harness connector at the K40 seat memory control module.
4. Test for infinite resistance between the control circuit terminals listed below and ground:
* Terminal 11
* Terminal 10
• If less than infinite resistance
Repair the short to ground on the circuit.
• If infinite resistance
5. Ignition ON.
6. Test for less than 1 V between the control circuit terminals listed below and ground:
* Terminal 11
* Terminal 10
• If 1 V or greater
Repair the short to voltage on the circuit.
• If less than 1 V
7. Replace the K40 seat memory control module.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
Control Module References Control Module References for seat memory control module replacement, programming and setup