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P0074 Code – What Does It Mean & How To Fix It

This is one of the most frequent OBD2 trouble codes. Read the full article below to know what it means, how to fix it, and what other codes may show related to it.


DTC stands for Diagnostic Trouble Codes, which are the standard system used by vehicles to communicate and identify possible malfunctions. The P0074 is a unique DTC code that corresponds to the transient air temperature sensor circuit.


The P0074 code indicates that there is an intermittent issue within the circuit of the Ambient Air Temperature (AAT) sensor. The temperature of the air in the vicinity of the vehicle shall be measured by an AAT sensor. The sensors help optimize the different systems, e.g. air-fuel mixture of an engine, for increased performance and fuel efficiency when they are able to provide reliable external temperature readings.


The activation of the P0074 code can be driven by a number of factors, including: 

  • Failed Ambient Air Temperature Sensor: The inability to provide consistent temperature readings can occur periodically in the AAT sensor, triggering a P0074 code.
  • Wiring Problems: Damaged or corroded wiring, loose connections, or intermittent short circuits in the AAT sensor circuit can lead to inconsistent signal transmission.
  • Sensor Placement: Incorrect installation or exposure of the AAT sensor to external elements may cause intermittent performance issues, resulting in the code’s activation. 
  • Electronic Control Module (ECM) Issues: Problems with the vehicle’s main computer, the ECM, can intermittently disrupt the interpretation of signals from the AAT sensor, leading to the code being triggered.


A number of symptoms may occur if a P0074 code is activated, including: 

  • Illuminated check engine lights: the common sign of trouble code, such as P0074, is an illuminated check engine light.
  • Unpredictable and erratic external temperature readings may be displayed on the vehicle’s display. 
  • Engine Performance Issues: Depending on the severity of the problem, you may experience reduced engine performance, decreased fuel efficiency, or other drivability concerns.


The following steps should be taken to diagnose the P0074 code accurately: OBDII Scanner: 

  • To retrieve the trouble code and all related codes stored on your car’s computer, an automotive mechanic will use an OBD II scanner.
  • Inspection: In order to ascertain the existence of apparent signs of damage, corrosion, and loose connections, an inspection shall be carried out by a thorough examination of the AAT sensor and its wires. 
  • Sensor Tests: the AAT sensor’s resistance, voltage, and temperature should be tested by a technician using a multimeter or special tools.
  • Circuit Testing: The wiring and circuitry associated with the AAT sensor will be examined for continuity, shorts, or intermittent open circuits.
  • ECM analysis: to determine whether any additional issues are contributing to code activation, we will analyze data from the EDM database if necessary.

Common mistakes

Common errors that can result in unnecessary repair or misdiagnosis should be avoided when dealing with the P0074 code: 

  • Neglecting fundamental checks: Before proceeding to a more complex diagnosis, it is appropriate to perform basic checks such as verifying the correct connection and checking for damaged wires.
  • Ignore related codes: It is possible to provide valuable information about the underlying issue by storing associated codes in the ECM. It can result in incomplete repairs if these codes are ignored. 
  • Skipping OEM Recommendations: In order to ensure a precise and efficient resolution of the P0074 code, it is important to follow the manufacturer’s diagnostic procedures, repair or replacement instructions.

How serious is this?

The specific circumstances and vehicle type have a direct bearing on the P0074 code’s seriousness. Although this may give you some small inconveniences such as incorrect temperature readings, failing to address it could result in undesirable engine performance, reduced fuel efficiency, or a possible detrimental effect on parts of the system. It is advisable to address this code immediately so that further complications can be avoided.

What repairs can fix the code?

repair manuals

The following corrections may have to be performed after determining the cause of the P0074 code: 

  • AAT replacement: If the AAT sensor malfunction or fails to function correctly, it should be replaced by a new reliable sensor in order to resolve the intermittent circuit problem.
  • To restore consistent signal transmission, it is necessary to repair or replace damaged or corroded wires, make sure connections are correct, and replace the wire harness. 
  • ECM repair or replacement: It is often necessary to repair or replace the computer in rare cases of an issue caused by an ECM.

Related codes

There are several related codes that may be associated with the P0074 code, including:

  • P0070: Ambient Air Temperature Sensor Circuit Malfunction
  • P0071: Ambient Air Temperature Sensor Range/Performance
  • P0072: Ambient Air Temperature Sensor Circuit Low Input

These related codes may provide additional insights into the underlying issue and assist in the diagnostic process.


For the diagnosis and resolution of problems with a vehicle, it is essential to understand the P0074 DTC code related to the ambient air temperature sensor circuit intermittent. You are better able to deal with the code in an effective manner by knowing its meaning, causes, symptoms, diagnosis methods, common errors, severity, possible repairs, and related codes.

It is advisable to consult with an expert automotive technician if the P0074 code has been detected or if you suspect that your AAT sensors are malfunctioning. The optimal functioning and reliability of your vehicle’s temperature measurement system will be ensured if the problem is detected promptly and appropriate repairs are made.

P0074 Code – What Does It Mean & How To Fix It