DTC P0506: Idle Control System Rpm Less Than Expected: Condition
WARNING: This page is about a different car, the 2002 Mazda 626. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
If ambient pressure is less than 21.3 in. Hg or intake air temperature is less than 14°F (-10°C), PCM cancels DTC P1506.
DTC is set when Powertrain Control Module (PCM) detects idle speed 100 RPM less than expected for 14 seconds when brake pedal is depressed (brake switch on) and steering wheel is held in straight ahead position (power steering pressure switch off). This is a continuous monitor. MIL is illuminated when PCM detects malfunction during 2 consecutive drive cycles. Possible causes are:
- IAC valve malfunction.
- Air cleaner element plugged.
- Air intake passage plugged.
- A/C relay control circuit malfunction.
- Generator control circuit malfunction.
- Low engine compression.
- PCM malfunction.