Code 51-01 OAT Open

What does 51-01 mean?

The Outdoor Air Thermistor (OAT) sensor circuit is open, meaning its resistance is too high. The system will use the Outdoor Coil Thermistor (OCT) instead and limit performance.

• Break in the wiring to the OAT sensor.
• Loose or damaged connector for the OAT sensor.
• Failing OAT sensor itself.
• Problem with the PCM (Processor Control Module) board.

Click steps to track your progress.

1. 1

   Visually inspect the OAT sensor wiring and its connector for any breaks, cuts, or loose connections.

2. 2

   Ensure the OAT sensor is securely plugged into its connection point.

3. 3

   If the wiring appears intact, the OAT sensor itself may need to be replaced by a technician.

4. 4

   If the sensor and wiring seem fine, a professional may need to check the PCM connection and resistance values.