P1519

Schematic:

CIRCUIT DESCRIPTION
When the ignition is turned to the ON position, the ECM operates the throttle valves in order to determine the integrity of the throttle control system prior to engine start-up. The ECM commands the throttle valves open momentarily and then commands the throttle valves to the closed position. Using information from the throttle position sensors, the ECM determines if the throttle valves are responding as commanded. The Engine Control Module (ECM) controls the throttle valves by applying a varying voltage to the throttle valve motor.

CONDITIONS FOR RUNNING THE DTC
^ The idle learn procedure is not active.
^ The duty cycle range switch is more than 80 percent.

CONDITIONS FOR SETTING THE DTC
The ECM determines that an open or a short to ground is present in the throttle valve motor circuit, or an internal circuit fault was detected.

ACTION TAKEN WHEN THE DTC SETS
The ECM illuminates the Malfunction Indicator Lamp (MIL) and records the operating conditions in the Freeze Frame on the first drive trip that the diagnostic runs and fails.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The ECM turns OFF the MIL after 3 consecutive drive trips that the diagnostic runs and passes.
^ A History DTC clears after 40 consecutive warm-up cycles in which there is no failure reported by this diagnostic or any other emission related diagnostic.
^ The scan tool clears the MIL/DTC.

TEST DESCRIPTION

Steps 1 - 8:

Steps 9 - 17:

The numbers below refer to the step numbers on the diagnostic table.
3. The throttle valves are spring loaded in a slightly open position and should move in either direction without binding. The throttle valves should always be under spring pressure.
6. When the ignition is turned ON, the ECM operates the throttle control motor to verify the integrity of the system prior to start-up. This can be seen by the momentary flash of the test lamp as the ignition is turned ON.