B1902 – Air Bag Crash Sensor #1 Ground Circuit Failure

The ODBII code B1902 indicates a failure in the ground circuit of Air Bag Crash Sensor #1, which can affect the airbag system’s ability to function properly in the event of a collision.

The severity of ODBII code B1902 is typically considered moderate to high.

Common Causes For: B1901 Air Bag Crash Sensor #1 Feed/Return Circuit Short To Ground

• Damaged wiring or connectors
• Corroded terminals
• Faulty airbag crash sensor
• Poor ground connection
• Short circuit in the wiring harness
• Open circuit in the ground path
• Faulty airbag control module

Common misdiagnosis for B1902 Air Bag Crash Sensor #1 Ground Circuit Failure

• Faulty airbag control module
• Defective airbag sensor
• Wiring issues unrelated to the ground circuit
• Faulty seat belt pretensioner
• Malfunctioning impact sensor
• Battery or power supply issues
• Corroded connectors or terminals
• Software or calibration errors in the airbag system

Common Troubleshooting Steps

When dealing with an OBD-II code B1902, which indicates an “Air Bag Crash Sensor #1 Ground Circuit Failure,” 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 B1902 code. Check for any additional codes that may provide more context.
• Visual Inspection:
• Inspect the wiring and connectors associated with the airbag system, particularly the crash sensor. Look for signs of damage, corrosion, or loose connections.
• Check the ground connections for the airbag system to ensure they are secure and free of corrosion.
• Check Ground Circuit:
• Use a multimeter to test the ground circuit for continuity. Disconnect the sensor and check the resistance between the ground terminal of the sensor and the vehicle’s ground. There should be minimal resistance (close to 0 ohms).
• If there is high resistance or no continuity, trace the ground wire back to its source and repair any breaks or poor connections.
• Inspect the Crash Sensor:
• If the wiring and ground circuit are intact, the crash sensor itself may be faulty. Check the sensor for any physical damage.
• If possible, test the sensor according to the manufacturer’s specifications. This may involve checking voltage and resistance values.
• Check for Short Circuits:
• Inspect the wiring harness for any signs of short circuits, such as frayed wires or pinched cables. Use a multimeter to check for shorts between the ground circuit and other circuits.
• Clear Codes and Test Drive:
• After performing repairs, clear the trouble codes using the OBD-II scanner. Take the vehicle for a test drive to see if the code reappears.
• Consult Service Manual:
• Refer to the vehicle’s service manual for specific diagnostic procedures and specifications related to the airbag system and crash sensor.
• Professional Help:
• If the issue persists after following these steps, consider seeking assistance from a professional mechanic or an automotive technician with experience in airbag systems.Safety Note: Working with airbag systems can be dangerous. Always follow safety precautions, such as disconnecting the battery and waiting for a period before working on the airbag system to avoid accidental deployment. If you’re unsure about any step, it’s best to consult a professional.