P0506

Schematic:

CIRCUIT DESCRIPTION
The Idle Air Control valve is a PCM controlled stepper motor located on the throttle body. The stepper motor drives a valve pintle which protrudes into a passage that bypasses the throttle plates. The PCM commands the IAC valve pintle to extend to decrease the idle speed. The bypass air flow is reduced and the idle speed decreases as the pintle approaches its seat. The PCM retracts the IAC valve pintle away from its seat to increase the idle speed. The retracting of the IAC valve pintle allows more air to bypass the throttle plates. The PCM uses the IAC system to maintain a desired idle speed. This DTC sets when the PCM detects an engine speed outside of the IAC's range of control.

CONDITIONS FOR RUNNING THE DTC
^ DTCs P0101, P0102, P0103, P0107, P0108, P0112, P0113, P0117, P0118, P0121, P0122, P0123, P0125, P0171, P0172, P0174, P0175, P0220, P0300, P0401, P0404, P0405, P0443, P0500-P0503, P1414 and P1441 are not set.
^ The engine run time is more than 60 seconds.
^ The engine coolant temperature is more than 60°C (140°F).
^ The intake air temperature is more than -10°C (14°F).
^ The barometric pressure is more than 65 kPa.
^ The ignition voltage is between 9.0 and 17.0 volts
^ The vehicle speed is no more than 1 mph (1.6 km/h).
^ The throttle position is less than 1 percent.

CONDITIONS FOR SETTING THE DTC
^ The actual idle speed is 100 RPM less than the desired idle speed.
^ All of the above conditions are present for 5 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
^ The PCM records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the PCM stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the PCM records the operating conditions at the time of the failure. The PCM writes the conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM turns the Malfunction Indicator Lamp (MIL) OFF after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A last test failed (current DTC) clears when the diagnostic runs and does not fail.
^ A History DTC clears after 40 consecutive warm-up cycles, if this or any other emission related diagnostic does not report any failures.
^ Use a scan tool in order to clear the MIL/DTC.

DIAGNOSTIC AIDS

IMPORTANT:
^ Remove any debris from the PCM connector surfaces before servicing the PCM. Inspect the PCM connector gaskets when diagnosing/replacing the PCM. Ensure that the gaskets are installed correctly. The gaskets prevent water intrusion into the PCM.
^ For any test that requires probing the PCM or a component harness connector, use the J 35616-A connector test adapter kit. Using this kit prevents damage to the harness/component terminals. Refer to Using Connector Test Adapters in Diagrams.

For an intermittent, refer to Symptoms. Symptom Related Diagnostic Procedures

TEST DESCRIPTION

Steps 1 - 6:

Steps 7 - 14:

The numbers below refer to the step numbers on the diagnostic table.
2. This test determines whether or not the engine can achieve the commanded RPM, and if not, whether the RPM is too high or too low.