Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means there's a problem with a part in your car that helps keep a sensor clean by blowing air on it. Think of it like a tiny fan that isn't working right.
The B0104 code indicates an issue with the control relay responsible for operating the air blower actuator, which is used to clean sensors.
The B0104 code is triggered when the vehicle's control module detects a malfunction in the relay that controls the air blower actuator. This actuator is designed to blow air over specific sensors to keep them free from dust and debris, ensuring accurate readings. A failure in this relay can lead to sensor contamination and incorrect sensor data being sent to the vehicle's control systems.
• Check engine light is on
• Sensors providing inaccurate data
• Possible decrease in vehicle performance
• Faulty air blower actuator relay
• Wiring issues or loose connections
• Blown fuse related to the actuator circuit
Actuator: A device that causes a machine or other device to operate.
Relay: An electrical device that opens or closes a circuit under the control of another electrical circuit.
• Check for any blown fuses in the actuator circuit
• Inspect wiring and connections for damage or corrosion
• Test the air blower actuator relay for proper operation
• Replace the faulty relay
• Repair or replace damaged wiring
• Ensure all connections are secure
• Multimeter
• Relay puller tool
• Screwdriver set
$50 - $150
Moderate
• Toyota Camry
• Honda Accord
• Ford Focus
• Regularly inspect and maintain electrical connections
• Replace relays at manufacturer-recommended intervals
• Keep sensors clean and free from debris
Sensor Issue
• Have the vehicle inspected by a professional if the check engine light comes on
• Regular maintenance can help prevent such issues
• Keep a log of any recurring issues for reference during repairs
Check with your vehicle manufacturer for warranty coverage on electrical components.
This code has been reported in vehicles with aging electrical systems, often due to wear and tear on relays and connectors.
Moderate – While the vehicle may still operate, sensor inaccuracies can lead to other issues if not addressed.
Driving with malfunctioning sensors can lead to safety risks and potential legal issues if the vehicle fails emissions tests.
• Vehicle at operating temperature
• Sensors free from external contamination
The air blower actuator relay is typically located in the fuse box under the hood or dashboard.
Q: Can I drive with the B0104 code?
A: It's possible to drive, but it's best to get it checked soon to avoid sensor issues.
Q: How can I prevent this code from appearing?
A: Regular maintenance and inspections of the electrical system can help prevent this issue.
Pro · Four-system diagnostics
A handheld scanner aimed at engine, transmission, ABS, and airbag diagnostic work.
Body and airbag faults often need a scanner that can access more than generic powertrain codes.
View on Amazon
Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking power, ground, and continuity in body-system circuits.
View on Amazon
Universal · Fuse kit
Useful for electrical diagnosis when blown fuses or circuit faults are part of the troubleshooting process.
Useful when body electrical faults trace back to blown fuses or shared circuits.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.