B3904
Rear Compartment Occupant Sensor Signal Invalid
B3904 is an OBD-II diagnostic trouble code meaning: Rear Compartment Occupant Sensor Signal Invalid. Common causes: rear passenger sensor malfunction, open or short circuit in wiring harness. Estimated repair cost: $56–167.
Symptoms
- Airbag light is on
- The passive safety system may not work in an accident.
- The error is stored in the memory of the control unit
Causes
- Rear passenger sensor malfunction
- Open or short circuit in wiring harness
- Poor contact in sensor connectors
- SRS control unit malfunction
How to Fix
- Check the integrity of the wiring harness to the sensor
- Check the contacts in the sensor and control unit connectors
- Test rear passenger sensor
- If necessary, replace the sensor or wiring harness
- Reset the error and check the system
Related codes
Error B3904 by Vehicle Brand
FAQ
What does the B3904 code mean?
B3904 is an OBD-II diagnostic trouble code that indicates: Rear Compartment Occupant Sensor Signal Invalid
What causes a B3904 error code?
The most common causes of B3904 include: Rear passenger sensor malfunction; Open or short circuit in wiring harness; Poor contact in sensor connectors; SRS control unit malfunction.
How do I fix a B3904 diagnostic trouble code?
To fix B3904: Check the integrity of the wiring harness to the sensor. Check the contacts in the sensor and control unit connectors. Test rear passenger sensor. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with B3904?
Limited driving only, diagnose soon
How much does it cost to fix B3904?
The estimated repair cost for B3904 is $56–167. Actual cost depends on your vehicle, location, and labor rates.
See also: Russian version · NationStat