Possible Cause
WARNING: This page is about a different car, the 2002 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:
- VPWR to IAC solenoid open (P0505, P1504 or P1507).
- IAC circuit open (P0505, P1504 or P1507).
- IAC circuit shorted to PWR (P0505, P1504 or P1507).
- IAC circuit shorted to GND (P1504).
- VPWR circuit open (P0505, P1504 or P1507).
- Air inlet plugged (P0505 or P1507).
- Air inlet leakage (P1507).
- Damaged IAC solenoid (P1504 or P1507).
- Damaged throttle body (P0505 or P1507).
- Damaged PCM (P0505, P1504 or P1507).