P0506
Diagnostic Chart (Part 1 Of 2):
Diagnostic Chart (Part 2 Of 2):
Schematic:
CIRCUIT DESCRIPTION
The Powertrain Control Module (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 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 higher number of counts indicates more commanded airflow, pintle retracted. 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 low of an idle speed is present and the PCM is unable to adjust Idle speed by increasing the IAC counts, DTC P0506 will set.
CONDITIONS FOR RUNNING THE DTC
^ No VSS, TP Sensor, EVAP System, Misfire, IAT Sensor, MAP Sensor, Fuel Trim, Fuel Injector, EGR Pintle Position, ECT Sensor, CKP Sensor, or MAF Sensor DTCs set.
^ BARO is more than 65 kPa.
^ Engine has been running for at least 2 minutes. System voltage is between 9-16 volts.
^ Engine coolant temperature is more than 70°C (158°F).
^ Vehicle speed is less than 3 mph.
^ Intake air temperature is more than -18°C (0°F).
^ The throttle is closed.
CONDITIONS FOR SETTING THE DTC
^ Engine speed is more than 100 RPM lower than Desired Idle. Negative idle speed error is more than 100 RPM.
^ The above conditions are present for longer than 15 seconds.
ACTION TAKEN WHEN THE DTC SETS
^ The PCM will illuminate the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.
^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.
^ If the misfire is determined to be catalyst damaging, the PCM will flash the MIL.
CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed.
^ The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The DTC can be cleared by using a scan tool.
DIAGNOSTIC AIDS
Inspect for the following conditions:
^ Restricted air intake system Inspect for a possible collapsed air intake duct, restricted air filter element, or foreign objects blocking the air intake system.
^ Throttle body-Inspect for objects blocking the IAC passage or throttle bore, excessive deposits in the IAC passage and on the IAC pintle, and excessive deposits in the throttle bore and on the throttle plate.
^ Large vacuum leak - Inspect for a condition that causes a large vacuum leak, such as an incorrectly installed or malfunctioning crankcase ventilation valve or brake booster hose disconnected.
IMPORTANT: Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
^ Poor terminal connection-Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension.
^ Damaged harness-Inspect the wiring harness for damage. If the harness inspection does not reveal a problem, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the scan tool display may indicate the location of the fault.
^ PCM and engine grounds for clean and secure connections
If the DTC is determined to be intermittent, reviewing the Failure Records can be useful in determining when the DTC was last set.
TEST DESCRIPTION
The number below refers to the step number 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.