P0071 code definition
Ambient Air Temperature Sensor Range/Performance Issue
Depending on the type of vehicle these are some related OBD-II Diagnostic Trouble Codes:
- P0070: Ambient Air Temperature Sensor Circuit
- P0072: Ambient Air Temperature Sensor Circuit Low Input
- P0073: Ambient Air Temperature Sensor Circuit High Input
What the P0071 code means
The ambient air temperature sensor provides the Power Control Module (PCM) with information that is necessary to monitor the ambient air temperature and intake air temperature. When the ambient air temperature to intake air temperature ratio is abnormal, this triggers the P0071 trouble code, causing the Check Engine Light to come on.
What causes the P0071 code?
The following are known causes for the P0071 trouble code:
- Failed or faulty ambient air temperature sensor
- A short in wires or broken wires
- An open or shorted ambient air temperature harness
- Corroded electrical circuitry and/or connectors
- Sensor covered by foreign objects
What are the symptoms of the P0071 code?
A Check Engine Light is the most common symptom of the P0071 trouble code. It is also possible that the climate control system (heat and/or air condition controls) will stop working as it should, indicating that there is a fault in the ambient air temperature sensor.
How does a mechanic diagnose the P0071 code?
Recording the freeze frame data and diagnostic trouble codes present is the first step in diagnosing the P0071 trouble code. This can be done by using an OBD-II scanner.
After receiving the P0071 trouble code from the OBD-II scanner, the wiring and connectors going to the ambient air temperature sensor should be inspected for shorts, breaks, and corrosion in the circuitry and/or connector. It is also a good idea to make sure that there isn’t anything covering the sensor, which could cause the P0071 code to be triggered.
After inspecting these components and repairing and/or replacing as needed, the trouble code should be cleared and the vehicle test driven. This part of the diagnostic process will ensure that the ambient air temperature sensor issue has been resolved and that there are no other problems attributing to the P0071 trouble code.
The ambient air temperature sensor will need to be replaced if the P0071 diagnostic trouble code quickly returns during the test drive. If the P0071 diagnostic trouble code returns, but the return is not immediate, an intermittent problem has been indicated and further diagnosis of the voltage going to the PCM would be required.
In very rare instances, when all of the above diagnostic measures do not resolve the ambient air temperature sensor issue, this could indicate that there is a problem with the Power Control Module (PCM). This is unusual, but is still a possibility.
Common mistakes when diagnosing the P0071 code
It is important to check the ambient air temperature sensor wiring and connector before replacing the sensor itself. Too often, the ambient air temperature sensor is replaced when a defect in the wiring and/or connector could have resolved the P0071 trouble code.
How serious is the P0071 code?
The ambient air temperature sensor could affect the climate control system (heat and/or air condition controls), which could cause uncomfortable driving conditions. The P0071 trouble code would not be classified as a serious one because it does not interfere with the vehicle's drivability function or prevent the car from running properly.
What repairs can fix the P0071 code?
- Repairing or replacing wires with shorts and/or breaks
- Cleaning corrosion in the electric circuitry and/or connector
- Replacing the faulty ambient air temperature sensor
Additional comments for consideration regarding the P0071 code
Although the most common solution to resolving the P0071 diagnostic trouble code will be to replace the ambient air temperature sensor, the wiring, connector, and harness need to first be excluded as the problem.
Need help with a P0071 code?
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This article originally appeared on YourMechanic.com as P0071 OBD-II Trouble Code: Ambient Air Temperature Sensor Range/Performance and was authored by Jamahl Walker.