Error Code P0074: What It Means & What To Do?

<<See All OBD Codes

The P0074 code is related to Ambient Air Temperature Sensor Circuit Intermittent. The meaning of this error code is that Ambient Air Temperature Sensor electrical circuit has some issue which is not constant. Doe to this the signal coming from the sensor to the engine control unit would keep on going on and off.

This error code gives an indication that the powertrain control module has received an uncommon signal from the ambient air temperature sensor. The most visible symptom of this condition is service engine soon lamp.

What causes this problem with the Ambient Air Temperature Sensor Circuit Intermittent?

• You can face an issue that the signal circuit to the AAT sensor might be opened up
• The voltage circuit to the AAT sensor can be opened up
• The problem of short to ground in the signal circuit to the AAT sensor
• The AAT sensor can be defective
• Powertrain control module may start failing

1. Powertrain Control Module - Faulty PCM can easily distorted engine timing causing frequent halting. Find all the Powertrain related parts with us.
2. Intake Air Temperature - Faulty Intake Air Temperature can flash and store wrong OBD error. It’s better to get the faulty Intake Air Temperature replaced as soon as possible.
3. Engine Coolant Temperature Sensor - OBD Error Code P0074 can simply be due to faulty Engine Coolant Temperature Sensor. Replace old and damage components now!
4. ECU - Faulty/damaged ECU will reduce the performance, fuel economy or emissions of the vehicle. Thus, it is important to replace it immediately.
5. Engine Light - If there is any fault detected in the Engine Light, it will get stored and flash OBD Code P0074. Replace faulty Engine Light components now!
6. Indicator Light - Did your mechanic just found out that there is some fault in the Indicator Light? Buy top notch Indicator Light from us at economical prices.
7. Air Conditioning - P0074 code can display due to some issues in the car Air Conditioning. So it is very important to replace the damaged Air Conditioning parts with us at equitable prices.
8. Instrument cluster - Do you remember when was the last time you got your car Instrument cluster repaired? A faulty Instrument cluster can cause a lot of issues like displaying P0074 code.

There can be some symptoms of the AAT sensor intermittent circuit due to which the ECU can start miscalculating the ambient air temperature to control the fuel to air ratio of the car engine and then it would let to the roughly running of the car engine as well as erratic when the circuit is not working. Now once the intermittent condition is detected by the engine control module, then the check engine light would start illuminating.

Common Symptoms

• The malfunction indicator light can start turning on
• The car air conditioning might stop working efficiently
• The instrument cluster may not be able to read outside temperature accurately
• The overhead console may not be able to read the outside temperature accurately

The defective ambient air temperature sensor should be replaced

There is no need to get strained if your OBD Code is still flashing up as we are here at your service. Have a look at our superior variety of ambient temperature sensor, intake air temp sensor, air intake sensor and many more. Now all your problems would vanish within no time.

• If your vehicle is equipped with an ambient temperature sensor (usually a two or three-wire variable resistance sensor), then it is designed in such a way to provide the PCM and the body control module with data
• The sensor has a voltage wire generally it is a 5-volt reference signal and a ground wire
• A reference voltage wires to monitor ambient air temperature is used by the power control module
• As ambient air temperature increases, sensor resistance keeps on decreasing and reference voltage would also increase
• When the ambient air becomes cool, then the sensor resistance is high, driving reference voltage to the powertrain control module goes down
• The PCM receives input reference voltage readings as variations in ambient air temperature and reacts according to the situation
• If in any case the ambient air temperature exceeds intake air temperature, a code is stored and a service engine soon lamp may start illuminating. You can diagnose this code with the help of a scanner or a code reader and a digital volt ohmmeter
• You can begin the diagnosis by visually inspecting all wiring as well as connectors
• You can always search for shorted or burned wiring and you can replace circuitry and connectors as per the requirement
• If you find out that the system wiring, connectors, and components are in normal working order, then you should connect the scanner to the diagnostic connector and record all stored trouble codes as well as freeze frame data
• This information can be extremely helpful in diagnosing intermittent conditions that may have contributed to this code being stored
• Once all the codes have been cleared, operate the vehicle to see if the code returns
• If the code fails to immediately return, you may have an intermittent condition
• Intermittent conditions can prove to be quite a challenge to diagnose and in extreme cases may have to be allowed to worsen before a correct diagnosis can be made. Proceed by unplugging the electrical connector from the ambient air temperature sensor and testing for reference voltage
• It is generally 5-volts but you can always consult your manufacturer’s service manual to avoid any confusion
• If there is a 5-volt signal present with the ignition turned to the run position, and then the sensor ground wire should be properly checked
• If both the reference signal and the ground signal are present, test the sensor resistance using the manufacturer’s temperature to resistance chart
• You can always compare your findings to the manufacturer’s specifications and replace the sensor if it fails to comply. If the sensor and voltage at the sensor are within acceptable specifications, disconnect the PCM electrical connector and test circuit continuity and resistance between the sensor and the PCM
• The system circuitry and components should be repaired or replaced as required and retest the system. All the system circuitry and sensors should be checked out; a defected PCM should be suspected but keep in mind that PCM failure is rare and PCM replacement would need proper reprogramming

Common Mistakes When Diagnosing the P0074 Code

You must not start assuming that there is some issue with the sensor unless and until you get your car wiring and connectors inspected properly to ensure that they have no issues. The ignition should be turned on and then the mechanic should check the car wiring as well as sensor. They can always use a multi meter as it would be helpful in checking the voltages in and out of the sensor. The ambient air temperature signal can be indicated with a 0-5-volt signal. If you find out that there is no voltage, then there is surely a circuit or sensor failure which must be determined.