B1438: Wiper Mode Select Switch Circuit Failure

Definition

The OBD2 code B1438 indicates a malfunction in the wiper mode select switch circuit, which may affect the operation of the windshield wipers

Common causes

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 misdiagnoses

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

Troubleshooting steps

1. 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
2. Inspect the Wiper Switch
3. Check the wiper mode select switch for any visible damage or wear
4. 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
5. Examine Wiring and Connectors
6. Inspect the wiring harness and connectors associated with the wiper mode select switch for any signs of damage, corrosion, or loose connections
7. Look for frayed wires or broken connectors that could interrupt the circuit
8. Test the Wiper Motor
9. Ensure that the wiper motor is functioning correctly. If the motor is faulty, it may not respond to the switch inputs
10. You can test the motor by applying direct power to it to see if it operates
11. Check the Body Control Module (BCM)
12. 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
13. Inspect the BCM for any signs of damage or failure
14. Inspect Fuses and Relays
15. Check the fuses related to the wiper system to ensure they are intact
16. Test the relays associated with the wiper system to ensure they are functioning properly
17. Look for Ground Issues
18. Ensure that the ground connections for the wiper system are secure and free of corrosion. Poor grounding can lead to circuit failures
19. Perform a Visual Inspection
20. Look for any signs of water intrusion or debris in the wiper assembly that could affect operation
21. Ensure that the wiper blades are not stuck or obstructed
22. Clear the Code and Test Drive
23. After performing the above checks and repairs, clear the trouble code using the OBD-II scanner
24. Take the vehicle for a test drive to see if the code reappears
25. Consult a Professional
26. 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

Definition

Common causes

Common misdiagnoses

Troubleshooting steps

1. Check for Additional Codes

2. Inspect the Wiper Switch

3. Check the wiper mode select switch for any visible damage or wear

4. 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

5. Examine Wiring and Connectors

6. Inspect the wiring harness and connectors associated with the wiper mode select switch for any signs of damage, corrosion, or loose connections

7. Look for frayed wires or broken connectors that could interrupt the circuit

8. Test the Wiper Motor

9. Ensure that the wiper motor is functioning correctly. If the motor is faulty, it may not respond to the switch inputs

10. You can test the motor by applying direct power to it to see if it operates

11. Check the Body Control Module (BCM)

12. 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

13. Inspect the BCM for any signs of damage or failure

14. Inspect Fuses and Relays

15. Check the fuses related to the wiper system to ensure they are intact

16. Test the relays associated with the wiper system to ensure they are functioning properly

17. Look for Ground Issues

18. Ensure that the ground connections for the wiper system are secure and free of corrosion. Poor grounding can lead to circuit failures

19. Perform a Visual Inspection

20. Look for any signs of water intrusion or debris in the wiper assembly that could affect operation

21. Ensure that the wiper blades are not stuck or obstructed

22. Clear the Code and Test Drive

23. After performing the above checks and repairs, clear the trouble code using the OBD-II scanner

24. Take the vehicle for a test drive to see if the code reappears

25. Consult a Professional

26. 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