P0073 Fault Code

P0073 OBD-II Trouble Code Short Description

Ambient Air Temperature Sensor Circuit High Input

What does trouble code P0073 mean?

The P0073 fault code indicates a problem with the ambient air temperature sensor circuit in a car. This code is triggered when the sensor detects a high voltage input, suggesting that the temperature being reported is too high or inaccurate.

The ambient air temperature sensor is located on the exterior of the vehicle, usually in the front bumper or grille area. Its purpose is to measure the temperature of the air around the vehicle, which is used by various systems in the car such as the climate control system and engine management system.

When the sensor circuit reports a high input, it can lead to incorrect temperature readings, which may affect the car's performance and efficiency. Some possible causes of this fault code could be a malfunctioning sensor, a short circuit in the wiring or connector, or an issue with the engine control module (ECM).

To diagnose and resolve this issue, the first step would be to visually inspect the sensor and its connection to ensure it is securely plugged in and free from any damage or corrosion. If there are no visible issues, further testing using a multimeter or scan tool may be required to determine if the sensor is functioning correctly or if there is a problem with the wiring.

If the sensor is found to be faulty, it will need to be replaced. In some cases, cleaning or repairing the connections may also resolve the issue. If the fault lies with the wiring or ECM, additional repairs or component replacements may be necessary.

It is important to address this fault code promptly, as incorrect temperature readings can lead to issues with fuel efficiency, emissions, and overall vehicle performance. Consulting with a qualified mechanic or utilizing diagnostic equipment is recommended to accurately diagnose and resolve the P0073 fault code.


What are the symptoms of the P0073 code?

Symptoms of the P0073 fault code (Ambient Air Temperature Sensor Circuit High Input) on cars may include:

  • Malfunctioning cabin temperature display
  • Inaccurate reading on the ambient air temperature gauge
  • Air conditioning system not functioning properly
  • Engine may hesitate or stall
  • Decreased fuel efficiency
  • Check Engine Light (CEL) or Malfunction Indicator Lamp (MIL) illuminates on the dashboard

Please note that these symptoms may vary depending on the make and model of the vehicle. It is always recommended to consult a professional mechanic or use a diagnostic tool for an accurate diagnosis.


What causes the P0073 code?

P0073 - Ambient Air Temperature Sensor Circuit High Input

The P0073 fault code on cars indicates a problem with the ambient air temperature sensor circuit, specifically a high input signal was detected. This fault code usually occurs when the sensor detects an abnormally high voltage or resistance on the circuit.

Possible causes of the P0073 fault code include:

  1. Faulty ambient air temperature sensor: The sensor may be malfunctioning, providing an incorrect reading to the engine control module (ECM).

  2. Wiring issues: Damaged or corroded wiring connections, open circuits, or shorts in the ambient air temperature sensor circuit can lead to the P0073 fault code.

  3. Faulty ECM: In rare cases, a malfunctioning ECM may be responsible for the high input signal detected by the ambient air temperature sensor circuit.

To diagnose and fix the P0073 fault code, the following steps can be taken:

  1. Inspect the ambient air temperature sensor and wiring connections for any visible damage, corrosion, or loose connections. Repair or replace as necessary.

  2. Test the resistance of the ambient air temperature sensor using a multimeter according to manufacturer specifications. If the sensor's resistance does not match the specified values, it may need to be replaced.

  3. If the sensor and wiring are in good condition, further diagnostic testing may be required using a scan tool or diagnostic equipment to pinpoint the exact cause of the high input signal. This may involve checking the voltage signal from the sensor, testing the ECM, or performing other related tests.

  4. Once the issue is identified and resolved, clear the fault code and test the system to ensure the P0073 code does not reappear.

It is recommended to consult the vehicle's repair manual or seek assistance from a certified mechanic for a proper diagnosis and repair of the P0073 fault code.

Possible Solutions

How to fix P0073?

To fix the P0073 fault code, which refers to the Ambient Air Temperature Sensor Circuit High Input, you can try the following steps:

  1. Inspect the sensor: Check the ambient air temperature sensor for any signs of damage, such as wires being frayed or connectors being loose. If any issues are found, repair or replace the sensor as necessary.

  2. Check the wiring: Inspect the wiring harness connected to the temperature sensor for any damages like cuts, breaks, or corrosion. Repair or replace any damaged wiring.

  3. Test the sensor: Use a multimeter to test the resistance of the ambient air temperature sensor. Compare the readings to the specifications provided by the manufacturer. If the readings are outside the acceptable range, replace the sensor.

  4. Clear the fault codes: After making any necessary repairs or replacements, use an OBD-II scanner to clear the fault codes from the vehicle's memory. This will reset the system and allow you to check if the issue has been resolved.

  5. Monitor the system: After clearing the fault codes, monitor the ambient air temperature sensor and its circuit to ensure that the P0073 code does not reappear. If the code returns, further diagnosis may be required.

Remember, if you are not confident in your ability to perform these steps or if the issue persists after attempting these fixes, it's recommended to seek assistance from a qualified mechanic or dealership.