P0507

Diagnostic Chart:

Wiring Diagram:

Circuit Description
The VCM controls the idle speed with an Idle Air Control (IAC) valve to a calculated desired RPM based on sensor inputs and actual engine RPM. The VCM uses 4 circuits in order to move an Idle Air Control (IAC) valve, allowing a varying amounts of air flow into the intake manifold.

In order to increase the idle RPM, the VCM moves the IAC valve out, allowing more air to bypass the throttle plate. In order to decrease the RPM, the VCM moves the IAC valve in, reducing the amount of air bypassing the throttle plate. A scan tool reads the VCM commands to the IAC valve in counts. The higher the counts, the more air that is allowed to bypass the throttle plate (higher idle). The lower the counts, the less air that is allowed to bypass the throttle plates (lower idle). This Diagnostic Trouble Code (DTC) is a type B DTC.

Conditions For Setting DTC

Non-intrusive

^ No TP sensor DTCs set.
^ No ECT DTCs set.
^ No Vehicle Speed Sensor (VSS) DTCs set.
^ No MAP DTCs set.
^ ECT is greater than 50°C.
^ IAT is greater than -25°C.
^ BARO is greater than 75 kPa (10,300 ft.).
^ Vehicle Speed is less than 2 mph.
^ System voltage is between 10 volts and 16 volts.
^ Engine run time is greater than 30 seconds.
^ TP is less than 1%.
^ Above met for a time greater than 3 seconds.

If the non-intrusive test fails, the intrusive test is ran.

Intrusive

^ Calculated Air Flow is between 17.5 grams per second and less than 50 grams per second.
^ Vehicle Speed is between 25 MPH and 85 MPH.
^ Change in TP Sensor is less than 1%.
^ Change in engine speed is less than 50 RPM.
^ IAC motor commanded to 10% for 100 msec.

Action Taken When the DTC Sets
The VCM will turn ON the Malfunction Indicator Lamp (MIL) after 2 consecutive driving cycles with the fault active.

Conditions for Clearing the MIL/DTC
The VCM turns the MIL off after 3 consecutive driving trips without a fault condition present. A history DTC will clear if no fault conditions have been detected for 40 warm-up cycles (coolant temperature has risen 40°F from the start-up coolant temperature and the engine coolant temperature exceeds 160°F during that same ignition cycle) or the scan tool clearing feature has been used.

Diagnostic Aids

The following items could cause this DTC:

^ An IAC valve which is stopped and cannot respond to the VCM.

^ A throttle stop screw which has been tampered with.

^ A damaged throttle or linkage.

A slow, unstable, or fast idle may be caused by a non - IAC valve system problem that cannot be overcome by the IAC valve. Out of range control IAC scan tool counts will read above 60 if the idle is too low and zero if the idle is too high. Check for the following:

^ Fuel system too lean and rich.

^ Throttle body - inspect the bore for foreign material.

^ Refer to Rough, Unstable, or Incorrect Idle, Stalling. Rough, Unstable, or Incorrect Idle, Stalling

^ IAC reset is done with the scan tool misc. functions mode.