P0507

Idle Speed High:

P0507- IDLE SPEED HIGH
The ECM can control idle speed by electrically controlling the throttle plate, advancing/retarding spark timing or increasing/decreasing the air/fuel ratio. The ability for the ECM to control the throttle plate is performed by the use of the throttle actuator control (TAC) module. This assembly (internal to the throttle body assembly) houses a DC motor along with two independent throttle position sensors, which relay the position of the throttle plate. The throttle plate is held open 7% to a mechanical stop by the use of spring pressure for minimum idle air and in the event of a motor circuit malfunction. The ECM monitors the throttle actuator control system for faults in the TP sensors, TAC motor circuit and for a correlation between the actual and desired throttle plate position. The ECM also compares its commanded idle speed to the actual idle speed to ensure idle control is in check. DTC P0507 will set if the actual idle speed is greater than a calibrated amount from the ECM commanded idle speed after a certain period of time.

DTC PARAMETERS
DTC P0507 will set if the actual idle speed is greater than 200 rpm from the ECM commanded idle speed when:
^ Condition exists for longer than 2 seconds after the ECM has attempted to correct the condition within a limited range
^ ECT is greater than 80°C (176°F)
^ TAT is greater than 34°C (93°F)
^ Vehicle speed = 0 mph
^ EVAP leak diagnostics are not running
^ No ECT, EVAP leak, EVAP purge solenoid, IAT, TP or vehicle speed DTCs have been set

DTC P0507 diagnostic runs continuously once the above conditions have been met.

P0507 is a type B DTC

DIAGNOSTIC AIDS

IMPORTANT: If an EGR. fuel trim, HO2S, MAF. misfire, system voltage or throttle actuator DTC is also set. diagnose that DTC first.

Verify the ECM ability to control engine speed by using the Scan tool to perform the ENGINE SPEED CONTROL special function. The test will allow the RPM to be raised or lowered in increments of 25, 100 and 500 rpm. Compare the actual ENGINE SPEED to the DESIRED IDLE SPEED. Both should be within 100 rpm of each other.

Make an underhood visual inspection first. Possible causes of high idle speed:
^ Vacuum leak
^ Air induction tubing cracked or damaged
^ System voltage out of range ECT sensor skewed