B1904 – OBD-II DTC

OBD-II DTC B1904 – Air Bag Crash Sensor #2 Feed/Return Circuit Failure

DTC B1904 meaning

DTC B1904 refers to a diagnostic trouble code indicating a failure in the feed/return circuit of Air Bag Crash Sensor #2. This code is part of the airbag system diagnostics and suggests that there is an issue with the electrical circuit that connects to the second crash sensor, which is crucial for the proper deployment of airbags during a collision.

DTC B1904 symptoms

Common symptoms associated with DTC B1904 may include:

• Illumination of the airbag warning light on the dashboard.
• Potential malfunction of the airbag system, leading to non-deployment in an accident.
• Diagnostic scanner may show the B1904 code along with other related codes.

DTC B1904 causes

Several factors can lead to the triggering of DTC B1904, including:

• Faulty Air Bag Crash Sensor #2.
• Damaged wiring or connectors in the feed/return circuit.
• Corrosion or poor connections at the sensor or module.
• Issues with the airbag control module itself.
• Accidental disconnection or damage during repairs or maintenance.

DTC B1904 seriousness

DTC B1904 is considered serious because it indicates a potential failure in the airbag system. If the airbag system is not functioning correctly, it may not deploy in the event of a collision, increasing the risk of injury to the occupants. Therefore, it is crucial to address this code promptly to ensure passenger safety.

How to diagnose DTC B1904

To diagnose DTC B1904, follow these steps:

1. Use an OBD-II scanner to confirm the presence of the B1904 code.
2. Inspect the wiring and connectors associated with Air Bag Crash Sensor #2 for any visible damage or corrosion.
3. Check the resistance and continuity of the feed/return circuit using a multimeter.
4. Test the functionality of Air Bag Crash Sensor #2 by replacing it with a known good sensor if necessary.
5. Examine the airbag control module for any faults or issues.

How to fix DTC B1904 step-by-step instructions

To fix DTC B1904, follow these steps:

1. Disconnect the vehicle’s battery to ensure safety while working on the airbag system.
2. Inspect and repair any damaged wiring or connectors in the feed/return circuit.
3. If the crash sensor is faulty, replace Air Bag Crash Sensor #2 with a new or tested good sensor.
4. Reconnect all connectors and ensure they are secure and free of corrosion.
5. Reconnect the vehicle’s battery.
6. Use an OBD-II scanner to clear the DTC and check if the code reappears after a test drive.

How to erase DTC B1904

To erase DTC B1904, follow these steps:

1. Connect an OBD-II scanner to the vehicle’s diagnostic port.
2. Turn on the ignition without starting the engine.
3. Navigate to the option to clear or erase trouble codes on the scanner.
4. Confirm the action to erase the DTC.
5. Disconnect the scanner and turn off the ignition.
6. Start the vehicle and monitor for any reoccurrence of the code.

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