• Inconsistent cabin temperature
• Air conditioning not working properly
• Check engine light may be on
• Faulty air temperature sensor
• Wiring issues or poor connections
• Malfunctioning climate control module
OBD-II: On-Board Diagnostics, a system for self-diagnosing and reporting vehicle issues.
HVAC: Heating, Ventilation, and Air Conditioning, the system that controls the interior climate of a vehicle.
• B0120
• B0122
This code means there's a problem with the car's temperature sensor that helps control the air conditioning. It's like when your thermometer at home is broken and can't tell if it's hot or cold.
B0121 is triggered when there is a malfunction in the air temperature sensor circuit.
The B0121 code indicates an issue with the interior air temperature sensor circuit, which is responsible for sending temperature data to the climate control system. This data helps the system adjust the heating and cooling to maintain the desired cabin temperature.
• Use an OBD-II scanner to confirm the code.
• Inspect the air temperature sensor and wiring for damage.
• Test the sensor with a multimeter to ensure it's functioning.
• Replace the faulty air temperature sensor.
• Repair or replace damaged wiring or connectors.
• Reset the system and clear the code.
• OBD-II scanner
• Multimeter
• Screwdrivers
$100 - $300
Moderate
• Toyota Camry
• Honda Accord
• Ford Focus
• Regularly inspect sensor connections.
• Keep the interior clean to prevent sensor blockage.
• Perform routine diagnostics to catch issues early.
Sensor Issue
• Have a professional inspect the system if unsure.
• Do not ignore the problem as it may lead to discomfort.
• Regular maintenance can prevent such issues.
Check your vehicle's warranty as sensor issues may be covered under emissions or powertrain warranties.
This code has been associated with climate control issues in vehicles with automatic temperature control systems.
Moderate – It affects comfort but not immediate safety.
Driving with a malfunctioning temperature sensor can lead to discomfort but is not typically a safety hazard.
• Vehicle at operating temperature
• Climate control system active
The air temperature sensor is usually located near the dashboard or within the HVAC system.
Q: Can I drive with a B0121 code?
A: Yes, but your climate control system may not work properly, leading to discomfort.
Q: How do I reset the B0121 code?
A: After repairs, use an OBD-II scanner to clear the code from the vehicle's computer.
