DTC P0506: Idle Control System, Rpm Less Than Expected: Condition

DTC is set when actual engine speed is 100 RPM less than programmed target speed for more than 14 seconds with brake pedal depressed and front wheels in straight ahead position. This is a continuous monitor. MIL is illuminated when Powertrain Control Module (PCM) detects malfunction during 2 consecutive drive cycles. Possible causes are:

• Idle Air Control (IAC) valve malfunction.
• Air filter or intake passage plugged.
• A/C relay control circuit malfunction.
• Generator control circuit malfunction.
• Purge solenoid valve malfunction.
• Low engine compression or to much blow by.
• PCM malfunction.