B1938 – Air Bag Passenger Circuit Short To Ground

The ODBII code B1938 indicates a short circuit in the passenger airbag circuit, meaning there is an unintended connection to ground that could affect the airbag’s operation.

The severity of ODBII code B1938 is moderate to high.

Common Causes For: B1937 Air Bag Passenger Pressure Switch Circuit Open

• Damaged wiring or connectors in the airbag system
• Faulty airbag module
• Shorted or damaged passenger airbag sensor
• Corroded or loose connections
• Faulty seat occupancy sensor
• Issues with the airbag control module
• Improper installation or repair of airbag components

Common misdiagnosis for B1938 Air Bag Passenger Circuit Short To Ground

• Faulty airbag module
• Defective passenger seat sensor
• Wiring issues or shorts in the harness
• Malfunctioning airbag control unit
• Incorrectly installed or damaged seat components
• Faulty connectors or terminals
• Issues with the vehicle’s body control module (BCM)

Common Troubleshooting Steps

When dealing with OBD-II code B1938, which indicates a “Passenger Air Bag Circuit Short to Ground,” it’s important to follow a systematic approach to troubleshoot the issue. Here are common troubleshooting steps:

• Scan Tool Verification:
• Use an OBD-II scanner to confirm the presence of the B1938 code. Check for any other related codes that may provide additional context.
• Visual Inspection:
• Inspect the wiring and connectors related to the passenger airbag system. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the wiring harness under the passenger seat, as it can be prone to wear and tear.
• Check for Ground Issues:
• Verify that the ground connections for the airbag system are secure and free of corrosion. A poor ground can cause short circuits.
• Inspect the Airbag Module:
• Check the airbag control module for any signs of damage or water intrusion. Ensure that all connectors are properly seated.
• Test the Passenger Airbag:
• If accessible, test the passenger airbag itself for continuity and resistance. Refer to the vehicle’s service manual for the specific resistance values.
• Check for Shorts:
• Use a multimeter to check for shorts in the wiring harness. Disconnect the airbag module and measure resistance between the airbag circuit wires and ground. A low resistance reading indicates a short.
• Examine the SRS System:
• Review the entire Supplemental Restraint System (SRS) for any other components that may be causing the issue, such as seat belt pretensioners or other sensors.
• Clear Codes and Test Drive:
• After performing repairs or adjustments, clear the codes using the OBD-II scanner and take the vehicle for a test drive to see if the code reappears.
• Consult Technical Service Bulletins (TSBs):
• Check for any TSBs related to the airbag system for your specific vehicle make and model. There may be known issues or recalls that could be relevant.
• Professional Diagnosis:
• If the issue persists after performing the above steps, consider seeking help from a professional technician who specializes in automotive electrical systems or airbag systems.Safety Note: Working with airbag systems can be dangerous due to the potential for accidental deployment. Always follow safety precautions, including disconnecting the battery and waiting a specified time before working on the airbag system. If unsure, consult a professional.