P0506

CIRCUIT DESCRIPTION
The throttle actuator motor is controlled by the TAC module using various inputs from the PCM which are communicated across serial data. The DC motor located on the throttle body drives the throttle plate. In order to decrease idle speed, the TAC module commands the throttle closed reducing air flow into the engine and the idle speed decreases. In order to increase idle speed, the TAC module commands the throttle plate open allowing more air to bypass the throttle plate. If the Actual idle RPM does not match the Desired idle RPM within a calibrated time, this DTC sets.

CONDITIONS FOR RUNNING THE DTC
^ No Misfire, EGR, TP, VSS, ECT, MAP, IAT, Fuel trim, Fuel injector, CKP or MAF DTCs set.
^ Engine is operating for at least 2 minutes.
^ ECT is more than -40°C (-40°F)
^ IAT is more than -40°C (-40°F)
^ BARO is more than 65 kPa
^ System voltage is between 9.0 and 18.0 volts Vehicle speed is less than 3 mph
^ APP indicated angle is less than 0.25 percent

CONDITIONS FOR SETTING THE DTC
^ The Actual idle speed is approximately 150 RPM lower than the Desired idle speed.
^ All above conditions present for 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/Failure Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn the MIL OFF 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:

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. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Diagrams.
^ Damaged harness.
Inspect the wiring harness for damage. If the harness appears to be OK, observe the display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the display may indicate the location of the fault. Refer to Wiring Repairs in Diagrams.
^ Inspect the PCM and the 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

Diagnostic Chart:

The numbers below refer to the step numbers on the diagnostic table.
2. This test determines whether or not the engine can achieve the commanded RPM, and if not, whether the RPM is too high or too low.