P0506

Diagnostic Chart:

Schematic:

The PCM controls the air entering into the engine with an Idle Air Control (IAC) valve. To increase the idle rpm, the PCM commands the pintle inside of the IAC valve away from the throttle body seat. This allows more air to bypass the throttle blade. To decrease the rpm, the PCM commands the pintle towards the throttle body seat. This reduces the amount of air bypassing the throttle blade. A scan tool will read the IAC valve pintle position in counts. The higher the counts, the greater the airflow that bypasses the throttle blade.

DTC PARAMETERS
DTC P0506 will set if idle speed is below desired idle by more than 100 rpm for 19 seconds and the following conditions have been met:
^ DTCs P0105, P0107, P0108, P0112, P0113, P0117, P0118, P0122, P0123, P0125, P0128, P0130, P0131, P0132, P0133, P0134, P0171, P0172, P0201-P0204, P0300, P0301, P0302, P0303, P0304, P0336, P0440, P0442, P0446, P0452, P0453, P0480, P0481, P0502, P0503, P1133, and P1441 are not set.
^ BARO is greater than 72 kPa.
^ Engine Coolant Temperature (ECT) is greater than 40°C (104°F).
^ Engine has been running more than 20 seconds.
^ IAC command is greater than 145 counts.
^ Idle has stabilized for 5 seconds.
^ The battery voltage is between 11.6 and 17 volts.

DIAGNOSTIC AIDS
^ Inspect the IAC valve electrical connection for proper mating.
^ Inspect the wiring harness for damage.
^ Inspect the throttle stop screw for signs of tampering.
^ Inspect the throttle linkage for signs of binding or excessive wear.
^ A slow or unstable idle may be caused by one of the following conditions:
- A too rich or too lean fuel system.
- Foreign material in the throttle body bore or in the air induction system.
- A leaking or a restricted intake manifold.
- Excessive engine overloading. Check for seized pulleys, pumps, or motors on the accessory drive.
^ Refer to "Rough, Unstable, or Incorrect Idle Stalling". Rough, Unstable, or Incorrect Idle and Stalling