Possible Cause
WARNING: This page is about a different car, the 2003 Mazda Tribute. However, it is still accessible from the selected car via links, so may be relevant.
Idle Air Control (IAC) valve controls engine speed and provides a dashpot function. IAC valve meters intake air around throttle plate through a bypass within IAC valve assembly and throttle body. PCM determines desired idle speed or bypass air and signals IAC valve through a specified duty cycle. The IAC valve responds by positioning to control amount of bypass air. Possible causes are:
- Air inlet leakage (DTC P1507).
- Air inlet plugged (DTCs P0505, P0506 or P1507).
- Damaged IAC solenoid (DTCs P1504 or P1507).
- Damaged throttle body (DTCs P0505, P0506 or P1507).
- Damaged PCM (DTCs P0505, P0506, P1504 or P1507).
- IAC circuit open (DTCs P0505, P0506, P1504 or P1507).
- IAC circuit shorted to GND (DTCs P1504).
- IAC circuit shorted to PWR (DTCs P0505, P0506, P1504 or P1507).
- VPWR circuit open (DTCs P0505, P0506, P1504 or P1507).
- VPWR to IAC solenoid open (DTCs P0505, P0506, P1504 or P1507).