P0073: Ambient Air Temperature Sensor Circuit High Input

Definition

The OBD2 code P0073 indicates that the ambient air temperature sensor circuit is reporting a high voltage input, which may suggest a malfunction in the sensor or its wiring

Common causes

Faulty ambient air temperature sensor
Open or shorted wiring in the sensor circuit
Corroded or damaged connectors
Poor ground connection
Faulty engine control module (ECM)

Common misdiagnoses

Faulty ambient air temperature sensor
Wiring issues or short circuits
Faulty engine control module (ECM)
Incorrect coolant temperature sensor readings
Issues with the HVAC system
Faulty or corroded connectors
Problems with the vehicle's electrical system
Incorrectly calibrated temperature gauge

Troubleshooting steps

1. Check the Code

Use an OBD-II scanner to confirm that the P0073 code is present. Clear the code and see if it returns after a short drive
2. Visual Inspection
3. Inspect the ambient air temperature sensor and its wiring for any visible damage, corrosion, or loose connections
4. Check the connector for any signs of moisture or dirt that could affect the sensor's performance
5. Test the Ambient Air Temperature Sensor
6. Locate the ambient air temperature sensor, which is usually mounted near the front of the vehicle, often in the grille area
7. Use a multimeter to measure the resistance of the sensor. Compare the readings to the manufacturer's specifications (usually found in the service manual)
8. If the resistance is outside the specified range, the sensor may be faulty and should be replaced
9. Check the Wiring and Connectors
10. Inspect the wiring harness for any signs of damage, such as fraying or short circuits
11. Ensure that the connectors are clean and securely attached. Look for bent pins or corrosion
12. Test the Signal Voltage
13. With the ignition on (engine off), measure the voltage at the sensor connector. The voltage should typically be within a specific range (check the service manual for exact values)
14. If the voltage is too high, trace the wiring back to the Engine Control Module (ECM) to check for shorts to power or ground
15. Check for Ground Issues
16. Ensure that the ambient air temperature sensor has a good ground connection. A poor ground can cause high voltage readings
17. Inspect Related Components
18. Check other sensors and components that may be related to the ambient air temperature sensor circuit, such as the Engine Coolant Temperature (ECT) sensor or the Intake Air Temperature (IAT) sensor, to ensure they are functioning correctly
19. ECM/PCM Check
20. If all other components and wiring are in good condition, the issue may lie with the Engine Control Module (ECM). Check for any software updates or known issues with the ECM
21. Clear Codes and Test Drive
22. After making any repairs or replacements, clear the codes and take the vehicle for a test drive to see if the P0073 code returns
23. Consult a Professional
24. If you are unable to resolve the issue after these steps, it may be best to consult a professional mechanic or technician who can perform more advanced diagnostics. By following these steps, you should be able to identify and resolve the issue causing the P0073 code

Definition

Common causes

Common misdiagnoses

Troubleshooting steps

1. Check the Code

2. Visual Inspection

3. Inspect the ambient air temperature sensor and its wiring for any visible damage, corrosion, or loose connections

4. Check the connector for any signs of moisture or dirt that could affect the sensor's performance

5. Test the Ambient Air Temperature Sensor

6. Locate the ambient air temperature sensor, which is usually mounted near the front of the vehicle, often in the grille area

7. Use a multimeter to measure the resistance of the sensor. Compare the readings to the manufacturer's specifications (usually found in the service manual)

8. If the resistance is outside the specified range, the sensor may be faulty and should be replaced

9. Check the Wiring and Connectors

10. Inspect the wiring harness for any signs of damage, such as fraying or short circuits

11. Ensure that the connectors are clean and securely attached. Look for bent pins or corrosion

12. Test the Signal Voltage

13. With the ignition on (engine off), measure the voltage at the sensor connector. The voltage should typically be within a specific range (check the service manual for exact values)

14. If the voltage is too high, trace the wiring back to the Engine Control Module (ECM) to check for shorts to power or ground

15. Check for Ground Issues

16. Ensure that the ambient air temperature sensor has a good ground connection. A poor ground can cause high voltage readings

17. Inspect Related Components

18. Check other sensors and components that may be related to the ambient air temperature sensor circuit, such as the Engine Coolant Temperature (ECT) sensor or the Intake Air Temperature (IAT) sensor, to ensure they are functioning correctly

19. ECM/PCM Check

20. If all other components and wiring are in good condition, the issue may lie with the Engine Control Module (ECM). Check for any software updates or known issues with the ECM

21. Clear Codes and Test Drive

22. After making any repairs or replacements, clear the codes and take the vehicle for a test drive to see if the P0073 code returns

23. Consult a Professional

24. If you are unable to resolve the issue after these steps, it may be best to consult a professional mechanic or technician who can perform more advanced diagnostics. By following these steps, you should be able to identify and resolve the issue causing the P0073 code