P0507
Circuit Description
The PCM controls engine idle speed by adjusting the position of the Idle Air Control (IAC) motor pintle. The IAC is a bi-directional motor driven by two coils. The PCM sends pulses (steps) to the IAC to extend or retract the IAC pintle into a passage in the Throttle body to decrease or increase air flow. The commanded IAC position (displayed in counts) can be monitored on the scan tool; a lower number of counts indicates less commanded airflow (pintle extended). This method allows highly accurate control of idle speed and quick response to changes in engine load. If the PCM detects a condition where too high of an idle speed is present and the PCM is unable to adjust idle speed by decreasing the IAC counts, DTC P0507 will set indicating a problem with the idle control system.
Conditions for Running the DTC
^ No Fuel injector faults, Misfire, Fuel Trim, EVAP, EGR, VSS, TP, IAT, MAP, ECT, CKP or MAF sensor DTCs set.
^ BARO is greater than 65 kPa.
^ Engine has been running for at least 3 minutes.
^ System voltage is between 9 and 18 volts.
^ Engine Coolant Temperature is greater than 70°C (158°F).
^ Vehicle Speed is less than 3 MPH.
^ Intake Air Temperature is greater than -18°C (0°F).
^ The Throttle is closed.
^ Conditions stable for at least 15 seconds.
Conditions for Setting the DTC
Engine Speed is more than 175 RPM higher than Desired Idle (positive idle speed error greater than 175 RPM).
Action Taken When the DTC Sets
^ The PCM illuminates the Malfunction Indicator Lamp 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 MIL Off after three consecutive drive trips 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 forty 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.
^ Interrupting the PCM battery voltage may or may not clear DTCs. This practice is not recommended.
Diagnostic Aids
Notice: Use the Connector Test Adapter Kit J 35616-A for any test that requires probing the following items:
^ The PCM harness connectors
^ The electrical center fuse/relay cavities
^ The component terminals
^ The component harness connector Using this kit will prevent damage caused by the improper probing of connector terminals. Check for the following conditions:
^ Poor connection at PCM or IAC motor. Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
^ Damaged harness. Inspect the wiring harness for damage.
^ Vacuum leak. Check for a condition that causes a vacuum leak, such as disconnected or damaged hoses, leaks at EGR valve and EGR pipe to intake manifold, leaks at Throttle body, malfunctioning or incorrectly installed PCV valve, leaks at intake manifold, etc.
^ Throttle body. Check for a sticking Throttle plate. Also inspect the IAC passage for deposits or objects which will not allow the IAC pintle to fully extend.
Reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to set occurs. This may assist in diagnosing the condition.
Test Description
Number(s) below refer to the step number(s) on the Diagnostic Table.
10. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.