* Poor Fuel Economy: The Powertrain Control Module (PCM) uses the AAT sensor input to adjust the air/fuel ratio. An inaccurate reading leads to either a rich (too much fuel) or lean (too little fuel) mixture, resulting in decreased fuel efficiency.
* Rough Idle or Stalling: An incorrect air/fuel ratio, especially a lean condition, can cause a rough idle, hesitation, or even stalling, particularly when the engine is cold.
* Hesitation or Lack of Power: Similar to rough idling, an inaccurate AAT reading can lead to hesitation during acceleration or a general lack of power.
* Check Engine Light (CEL): The PCM will likely detect a problem with the AAT sensor and illuminate the check engine light, storing a diagnostic trouble code (DTC). This code will need to be read with an OBD-II scanner to pinpoint the issue.
* Incorrect Emissions: The inaccurate fuel mixture could lead to higher emissions, potentially failing an emissions test.
It's important to note that while these are common symptoms, a bad AAT sensor isn't the *only* cause of these issues. Other problems could be responsible, so proper diagnostics using an OBD-II scanner are necessary to pinpoint the root cause. A mechanic can also test the sensor directly to confirm its functionality.
