P2199 indicates that the powertrain control module (PCM) has detected a mismatch between the readings of the two intake air temperature (IAT) sensors on bank 1. The PCM expects the sensors to correlate within a specific range; when they diverge beyond that threshold, the code is set. This usually points to a problem with one of the sensors, its wiring, or the connector rather than the PCM itself.
One of the intake air temperature sensors may have failed internally, providing an incorrect voltage or resistance signal that does not match the other sensor.
Damage to the wires connecting the IAT sensors to the PCM can cause intermittent or incorrect readings, leading to a correlation fault.
Poor electrical contact at the sensor or PCM connector can introduce noise or signal loss, causing the PCM to see a mismatch between the two sensors.
If an IAT sensor is not seated correctly or there is an air leak near the sensor tip, the measured temperature may be inaccurate relative to the other sensor.
A fault inside the PCM’s IAT sensor input circuitry can produce erroneous correlation, but this is uncommon and should be considered only after sensor and wiring checks.
No. Replacing the PCM is rarely needed for P2199. The code is almost always caused by a faulty IAT sensor, wiring, or connector. PCM replacement should be a last resort after those components have been verified as good.
A dirty air filter alone does not trigger P2199. However, if it leads to abnormal airflow temperature extremes that affect sensor readings, it could contribute indirectly, but the primary causes remain sensor or wiring issues.
Clearing the code can be part of the diagnostic process, but if the underlying fault is present, the code will return. It is better to perform the inspection and tests first to avoid unnecessary repeat trips.