Intake Air Temperature Sensor 2 Circuit Intermittent/Erratic
This code indicates that the PCM has detected a voltage reading that is out of the normal range for the intake air temperature sensor 2 circuit.
Code Set Parameters
A voltage or resistance reading that exceeds a variation of greater than 10-percent of the manufacturer’s reference voltage will cause a trouble code to be stored and a malfunction indicator illuminated.
A trouble code will be stored and a malfunction indication illuminated.
The most common cause of this code is an IAT sensor that has been left unplugged after replacing the air filter. Other possible causes are a faulty IAT sensor (usually near the air filter housing), faulty electrical wiring or connectors, a faulty PCM.
IAT sensor failure is rare and most problems can be contributed to a disconnected electrical connector.
- If your vehicle is equipped with an intake air temperature sensor (usually a two or three-wire variable resistance sensor), it is designed to provide the PCM and the body control module (for convenience display items) with data
- The sensor has a voltage wire (typically it is a 5-volt reference signal) and a ground wire
- The PCM uses the reference voltage wire to monitor intake air temperature
- As intake air temperature increases, sensor resistance decreases and reference voltage increases
- When intake air is cool, sensor resistance is high, driving reference voltage to the PCM down
- The PCM receives input reference voltage readings as variations in intake air temperature and reacts accordingly
- If ambient air temperature exceeds intake air temperature, a code is stored and a service engine soon lamp is illuminated.
You will need a scanner or a code reader and a digital volt ohmmeter to successfully diagnose this code.
Begin your diagnosis by visually inspecting all wiring and connectors
- Look for shorted or burned wiring and replace circuitry and connectors as required
If the system wiring, connectors, and components appear to be in normal working order, connect the scanner to the diagnostic connector and record all stored trouble codes and freeze frame data
- This information can be extremely helpful in diagnosing intermittent conditions that may have contributed to this code being stored
- After the codes are 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 intake air temperature sensor and testing for reference voltage
- This is usually 5-volts but consult your manufacturer’s service manual to be sure
- If there is a 5-volt signal present with the ignition turned to the run position, check the sensor ground wire
- If both the reference signal and the ground signal are present, test the sensor resistance using the manufacturer’s temperature to resistance chart
- 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
- Repair or replace system circuitry and components as required and retest the system.
Should all system circuitry and sensors check out, suspect a faulty PCM but keep in mind that PCM failure is rare and PCM replacement will require reprogramming.
You may also compare scanner temperature readings for the intake air temperature with the actual ambient temperature
- The temperature readings should be within 50-degrees of one another
- If temperature readings do not coincide with manufacturer’s specifications, remove the sensor itself and test it in ambient air
- If the sensor proves to read correctly, then test the electrical connector at the sensor and work backward toward the PCM.