B1438 – Wiper Mode Select Switch Circuit Failure

The ODBII code B1438 indicates a malfunction in the wiper mode select switch circuit, which may affect the operation of the windshield wipers.

The severity of ODBII code B1438 is generally considered moderate.

Common Causes For: B1437 Wiper Hi/Low Speed Relay Coil Circuit Short To Ground

• Faulty wiper mode select switch
• Damaged wiring or connectors
• Short circuit in the circuit
• Open circuit in the circuit
• Corrosion or poor connections
• Malfunctioning body control module (BCM)
• Faulty ground connection

Common misdiagnosis for B1438 Wiper Mode Select Switch Circuit Failure

• Faulty wiper motor
• Bad wiper relay
• Wiring issues or shorts in the harness
• Malfunctioning body control module (BCM)
• Incorrectly installed or damaged wiper switch
• Issues with the fuse related to the wiper system
• Problems with the windshield washer pump or circuit

Common Troubleshooting Steps

The OBD-II code B1438 indicates a problem with the Wiper Mode Select Switch Circuit. This code typically relates to the windshield wiper system and can be triggered by various issues. Here are some common troubleshooting steps to diagnose and potentially resolve the problem:

• Check for Additional Codes: Use an OBD-II scanner to check for any other related trouble codes. This can provide more context and help identify if there are multiple issues.
• Inspect the Wiper Switch:
• Check the wiper mode select switch for any visible damage or wear.
• Ensure that the switch is functioning properly. You can test the switch with a multimeter to see if it is sending the correct signals when toggled.
• Examine Wiring and Connectors:
• Inspect the wiring harness and connectors associated with the wiper mode select switch for any signs of damage, corrosion, or loose connections.
• Look for frayed wires or broken connectors that could interrupt the circuit.
• Test the Wiper Motor:
• Ensure that the wiper motor is functioning correctly. If the motor is faulty, it may not respond to the switch inputs.
• You can test the motor by applying direct power to it to see if it operates.
• Check the Body Control Module (BCM):
• The BCM may be responsible for interpreting the signals from the wiper switch. If the BCM is malfunctioning, it may not process the switch inputs correctly.
• Inspect the BCM for any signs of damage or failure.
• Inspect Fuses and Relays:
• Check the fuses related to the wiper system to ensure they are intact.
• Test the relays associated with the wiper system to ensure they are functioning properly.
• Look for Ground Issues:
• Ensure that the ground connections for the wiper system are secure and free of corrosion. Poor grounding can lead to circuit failures.
• Perform a Visual Inspection:
• Look for any signs of water intrusion or debris in the wiper assembly that could affect operation.
• Ensure that the wiper blades are not stuck or obstructed.
• Clear the Code and Test Drive:
• After performing the above checks and repairs, clear the trouble code using the OBD-II scanner.
• Take the vehicle for a test drive to see if the code reappears.
• Consult a Professional:
• If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician for further diagnosis. By following these troubleshooting steps, you should be able to identify and resolve the issue related to the B1438 code.