Chevrolet Trax: DTC B242A (WITH MEMORY A45): Seat heaters common circuit

Diagnostic Instructions

• Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
• Review Strategy Based Diagnosis for an overview of the diagnostic approach.
• 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 memory 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 s 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 (Encore), Heated/Cooled Seat Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Description and Operation

Heated Seats Description and Operation

Electrical Information Reference

• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs

Scan Tool Reference

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 infinite resistance between the B+ circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance

3. 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 fuse.
• 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 after completing the repair.

Control Module References for K40 Seat Memory Control Module replacement, programming and setup

SYMPTOMS - SEAT HEATING AND COOLING

NOTE: The following steps must be completed before using the symptom tables.

1. When diagnosing a heated seat system condition perform the Diagnostic System Check - Vehicle , before using the symptom tables in order to verify that all of the following are true:

• There are no DTCs set.
• The control module(s) can communicate via the serial data link.

2. Review the system operation in order to familiarize yourself with the system functions. Refer to Heated Seats Description and Operation.

Visual/Physical Inspection

• Inspect for aftermarket devices which could affect the operation of the power seats. Refer to Checking Aftermarket Accessories .
• Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
• Inspect the seat adjuster track for conditions which may cause binding or objects within the seat adjustment range which obstruct movement or interfere with wiring.

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections .

Symptom List

Refer to the Front Heated Seat Malfunction (Without Memory A45), Front Heated Seat Malfunction (With Memory A45) diagnostic procedure in order to diagnose the symptom.

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