Technical Description of OBD-II Trouble Code
Malfunction in the Circuit of Intake Air Temperature Sensor 2 in Bank 2
What does that signify?
This diagnostic trouble code (DTC) is a generic powertrain code that is applicable to vehicles equipped with OBD-II. Although it is a generic code, the specific repair steps may vary depending on the make and model of the vehicle.
The Intake Air Temperature (IAT) sensor is a thermistor that measures air temperature by detecting resistance in the air. It is typically located in the intake air ductwork, but in some cases, it may be found in the intake manifold. The sensor is supplied with a 5 volt reference wire (which also serves as a signal wire) from the Powertrain Control Module (PCM) and a ground wire.
As air flows over the sensor, the resistance changes, which in turn affects the 5 volts supplied to the sensor. Colder air leads to higher resistance and higher signal voltage, while warmer air results in lower resistance and lower signal voltage. The PCM monitors this change in voltage and calculates the air temperature to optimize engine operation at different temperatures.
If the PCM detects a voltage that is outside the normal operating range for the #2 sensor on bank 2, it will trigger a P00A5 code. Bank 2 refers to the side of the engine that does not contain cylinder #1.
Other related trouble codes for Bank 2 IAT sensor 2 include:
Symptoms
There may not be any noticeable symptoms other than the illumination of the Malfunction Indicator Lamp (MIL). However, there is a possibility of experiencing poor drivability complaints.
Causes
Possible causes of the P00A5 DTC include:
Possible Solutions
First, visually inspect the IAT sensor to ensure it is properly in place and has not been dislodged. As a quick check, use a scan tool to check the IAT reading with the Key On Engine Off (KOEO). If the engine is cold, the IAT reading should be the same as the Coolant Temperature Sensor (CTS) reading. If there is a significant variance (e.g. indicating an extreme temperature like -40°F or 300°F), there is likely a problem. Unplug the IAT sensor and perform a resistance test across the two terminals.
Each sensor will have different resistance values, so refer to a repair manual for the specific information. If the resistance of the IAT sensor is not within specifications, replace the sensor. There should be some resistance, so if it measures infinite resistance, replace the sensor.
If the issue persists, here is some additional diagnostic information:
1. If the KOEO IAT reading is at the high extreme (e.g. 300°F, which is obviously inaccurate), disconnect the IAT sensor. If the reading now shows the lowest extreme (around -50°F), replace the IAT sensor. However, if unplugging the IAT does not change the reading, turn off the ignition and disconnect the PCM connector. Use a voltmeter to check for continuity between a good ground and the signal wire to the IAT. If there is continuity, there may be a short to ground on the signal wire. If there is no continuity, the PCM may be faulty.
2. If the KOEO IAT reading is at the low extreme, disconnect the IAT connector. Check that there is 5 volts on the signal wire and that the other wire is grounded.
a. If there is 5 volts present and a good ground, jumper the two terminals together. The scanner reading should now be at the high extreme. If it is, replace the IAT sensor. However, if the reading remains low even after jumpering the wires, there may be an open in the wiring harness or a problem with the PCM.
b. If there is no 5 volts present, check for reference voltage at the PCM connector. If it is present at the PCM but not at the IAT sensor, repair the open in the signal wire.
