P0072 OBD-II Trouble Code: Ambient Air Temperature Sensor Circuit Low

P0072 code definition

Ambient Air Temperature Sensor Circuit Low Input

Depending on the type of vehicle these are some related OBD-II Diagnostic Trouble Codes:

• P0070: Ambient Air Temperature Sensor Circuit
  
• P0071: Ambient Air Temperature Sensor Range/Performance
  
• P0073: Ambient Air Temperature Sensor Circuit High Input
  

What the P0072 code means

The power control module (PCM) and the ambient air temperature sensor work together to ensure the ambient air temperature does not reach levels that are higher than the intake air temperature. If this happens, the ambient air temperature sensor sends that information to the PCM, which then stores the P0072 trouble code. The Check Engine Light will come on to alert the driver of a problem in the engine.

What causes the P0072 code?

• An ambient air temperature sensor that is not working properly
• Broken or shorted wires
• Corrosion in the electric circuitry or the connector
• Ambient air temperature harness break or short
• Sensor covered by debris

What are the symptoms of the P0072 code?

The Check Engine Light will come on, and sometimes the climate control system (heat and/or air condition controls) will not work properly.

How does a mechanic diagnose the P0072 code?

• A technician will use an OBD-II scanner to get information from the PCM about why the Check Engine Light is on.

• Using the OBD-II scanner will allow the technician to record freeze frame data about the trouble codes that have been stored by the PCM.

• If the P0072 trouble code is present, the technician will then inspect the ambient air temperature sensor to make sure that there is no debris covering the sensor.

• The technician will also inspect the wires and connector for shorts, opens, wires that are bare, and corrosion in the connector.

• If necessary, these components will be repaired or replaced and the technician will clear the trouble code and conduct a test drive to see if the P0072 trouble code returns.

• If the P0072 trouble code does not return, the ambient air temperature sensor error has been resolved and the sensor does not need to be replaced.

• If the P0072 trouble code returns immediately, the ambient air sensor will need to be replaced.

• If the P0072 trouble code takes some time before it returns, this indicates that there may be an intermittent problem with the voltage going to the PCM, which will require further diagnosis.

• Very rarely, when these diagnostic steps have not resolved the P0072 ambient air temperature sensor trouble code, it may be an indication that there is a problem with the PCM.

Common mistakes when diagnosing the P0072 code

The most common mistake that is made when diagnosing the P0072 trouble code is that the ambient air temperature sensor is replaced without first inspecting the wiring and connector. If this is the first step that technicians take in the diagnostic and repair process, it will prevent having to replace an ambient air temperature sensor that is otherwise in good operation condition.

How serious is the P0072 code?

A faulty ambient air temperature sensor may prevent the climate control system (heat and/or air condition controls) from working properly.

Depending on weather and the driver’s preferences, this could make driving conditions uncomfortable. The P0072 trouble code is not considered a serious one because it does not prevent the car from running or affect its drivability.

What repairs can fix the P0072 code?

• Repairing or replacing wires that have broken or shorted
• Clearing the electric circuitry and/or connector from corrosion
• Replacing the ambient air temperature sensor

Additional comments for consideration regarding the P0072 code

The quickest and easiest way to resolve the ambient air temperature sensor problem is to replace the sensor itself, which is why this is also the most common mistake that is made. It is important to emphasize the importance of checking the ambient air temperature sensor’s wiring, connector, and harness to see if these things are the cause of the P0072 trouble code before replacing the sensor.

Need help with a P0072 code?

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