P0507

DTC P0507

CIRCUIT DESCRIPTION




The engine idle speed is controlled by the idle air control (IAC) valve. The IAC valve is on the throttle body. The IAC valve pintle moves in and out of an idle air passage bore to control air flow around the throttle plate. The valve consists of a movable pintle, driven by a gear attached to a two phase bi-polar permanent magnet electric motor called a stepper motor. The stepper motor is capable of highly accurate rotation, or of movement, called steps. The stepper motor has two separate windings that are called coils. Each coil is fed by two circuits from the engine control module (ECM). When the ECM changes polarity of a coil, the stepper motor moves one step. The ECM uses a predetermined number of counts to determine the IAC pintle position. Observe IAC counts with a scan tool. The IAC counts will increment up or down as the ECM attempts to change the IAC valve pintle position. An IAC Reset will occur when the ignition key is turned OFF. First, the ECM will seat the IAC pintle in the idle air passage bore. Second, the ECM will retract the pintle a predetermined number of counts to allow for efficient engine start-up. If the engine idle speed is out of range for a calibrated period of time, an idle speed DTC P0507 may set.

CONDITIONS FOR RUNNING THE DTC
- DTCs P0106, P0107, P0108, P0117, P0118, P0122, P0123, P0300, P0336, P0340, P0341, P0500, and P0641 are not set.
- The ECT Sensor parameter is more than 50°C (122°F).
- The IAT Sensor parameter is more than -25°C (-13°F)
- The BARO parameter is more than 70 kPa.
- The Engine Run Time parameter is more than 3 seconds.
- The Ignition 1 Signal parameter is between 9-18 volts.
- The Vehicle Speed parameter is 0 km/h (0 mph).
- The TP Sensor parameter is 0 percent.

CONDITIONS FOR SETTING THE DTC
The actual engine speed is 200 RPM more than the desired engine speed for more than 17 seconds.

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

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

DIAGNOSTIC AIDS
Inspect for the following conditions:
- A high resistance in an IAC circuit
- The correct positive crankcase ventilation (PCV) valve, properly installed and proper operation of the PCV valve
- The proper operation and installation of all air intake components
- The proper installation and operation of the mass airflow (MAF) sensor, if equipped
- A tampered with or damaged throttle stop screw
- A tampered with or damaged throttle plate, throttle shaft, throttle linkage, or cruise control linkage, if equipped
- A misadjusted throttle cable
- A skewed high throttle position (TP) sensor
- Excessive deposits in the IAC passage or on the IAC pintle
- Excessive deposits in the throttle bore or on the throttle plate
- Vacuum leaks
- A high or unstable idle condition could be caused by a non-IAC system condition that can not be overcome by the IAC valve. Refer to Symptoms - Computers and Control Systems. Symptom Related Diagnostic Procedures
- If the condition is determined to be intermittent, refer to Intermittent Conditions. Diagnostic Strategies

TEST DESCRIPTION

Steps 1 - 6:

Steps 7 - 14:

Steps 15 - 18:

The numbers below refer to the step numbers on the diagnostic table.
5. This test will determine the ability of the ECM and IAC valve control circuits to control the IAC valve.
7. This test will determine the ability of the ECM to provide the IAC valve control circuits with a ground. On a normally operating system, the test lamp should not flash while the IAC Counts are incrementing.