P0507

Diagram Chart:

CIRCUIT DESCRIPTION

The IAC system controls the idle speed by allowing a controlled amount of air to bypass the throttle blade via a passage in the IAC valve. One of the ECM's uses for the IAC system is to maintain a desired idle speed, which can vary depending on input to the ECM and other criteria. If the ECM detects that the engine speed is outside of the IAC system's range of control at idle, a DTC will set.

CONDITIONS FOR RUNNING THE DTC

^ The following DTCs are not set: P0115, P0116, P0120, P0440, P0441, P0443, P0501, P0505.

^ The IAT is greater than -8.3°C (17°F)

^ The ECT is greater than 80.3°C (176.5°F)

^ The EVAP diagnostic is not running

^ The EVAP is not purging

^ The Vehicle speed = 0

CONDITIONS FOR SETTING THE DTC

^ The actual engine RPM is greater than the Desired Idle Speed by at least 200 RPM.

^ The Short Term Air Trim is lower than -1.66 g/s

^ The above condition met for more than 8 seconds

OR

^ The fuel cutoff occurs more than 3 times when the diagnostic is performed.

^ The above conditions met for longer than 8 seconds.

ACTION TAKEN WHEN THE DTC SETS

The ECM illuminates the Malfunction Indicator Lamp (MIL) and records the operating conditions in the Freeze Frame on the second consecutive drive trip that the diagnostic runs and fails.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The ECM turns off the MIL after three consecutive drive trips that the diagnostic runs and does not fail.

^ A History DTC clears after forty consecutive warm-up cycles if no failures report by this diagnostic or any other emission related diagnostic.

^ The ECM battery voltage is interrupted.

^ The scan tool clears the MIL/DTC.

DIAGNOSTIC AIDS

Use the Connector Test Adapter Kit J 35616-A for any test that requires probing the ECM harness connector or a component harness connector. Using this kit will prevent damage to the harness connector terminals.

Check for the following conditions:

^ Poor connections at the ECM or at the component. Inspect the harness connectors for any backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection. Refer to Overall Vehicle Information / Diagrams / Diagnostic Aids for Terminal Contact Checking procedure.

^ Damaged harness. Inspect the wiring harness for any damage. If the harness appears to be OK, observe the scan tool while moving the related connectors and the wiring harnesses. A change in the display may help in order to locate the fault.

Refer to Symptoms / Intermittents. Testing and Inspection

TEST DESCRIPTION

The number(s) below refer to the step number(s) on the Diagnostic Table.

2. Verifies that the fault is currently present.

4. The IAC valve is very sensitive to dirt and other contaminants. If contaminants are allowed to enter the air intake system, the IAC operation may be affected. Make sure that the duct work and the air cleaner assembly are absolutely clean. Check the IAC valve for dirt contamination. Do Not immerse the IAC valve in carburetor cleaners or other chemical solvents. If deposits are present, clean the IAC shutter and air passages using a GM Top Engine Cleaner, PIN 1052626 or AC-Delco Carburetor Tune-Up Conditioner, P/N X66-P, or an equivalent product. The IAC valve should be blown out with compressed air and the shutter checked for free movement. If free movement of the shutter cannot be restored, replace the valve and gasket.

NOTICE: Do not use any solvent that contains Methyl Ethyl Ketone (MEK). This solvent may damage fuel system components.

5. The IAC valve is very sensitive to dirt and other contaminants. If contaminants are allowed to enter the air intake system, the IAC operation may be affected. Make sure that the ductwork and the air cleaner assembly are absolutely clean. Check the IAC valve for dirt contamination. Do Not immerse the IAC valve in carburetor cleaners or other chemical solvents. If deposits are present, clean the IAC shutter and air passages using a GM Top Engine Cleaner, P/N 1052626 or AC-Delco Carburetor Tune-Up Conditioner, P/N X66-P, or an equivalent product. The IAC valve should be blown out with compressed air and the shutter checked for free movement. If free movement of the shutter cannot be restored, replace the valve and gasket.