Circuit Description
The throttle actuator control (TAC) module contains a direct current actuator motor controlled by the engine control module (ECM) used to move the throttle plate, in either direction and 2 throttle position (TP) sensors to determine throttle plate position. The throttle plate is held at a 7 percent rest position to a mechanical stop by a constant force return spring. This spring will hold the throttle plate to the stop when there is no current flowing to the actuator motor. There is another return spring, which creates constant force on the throttle plate only when the throttle plate is moved towards the full closed position. The ECM will monitor both the actuator motor and TP sensors for circuit faults as well as check to make sure both springs can return the throttle to the 7 percent position no matter where the throttle plate remains. DTC P1519 will set if the driver internal to the ECM that controls the actuator motor shuts OFF due to an over-temperature/over-current condition for a certain length of time.
Conditions for Setting the DTC
DTC P1519 will set if the throttle actuator motor driver internal to the ECM shuts OFF due to an overtemperature/overcurrent condition for longer than 5 seconds.
DTC P1519 diagnostic runs continuously with the engine running.
DTC P1519 is a type A DTC.
The malfunction indicator lamp (MIL) will only illuminate if the fault is present for longer than 5 seconds.
Diagnostic Aids
Important: If DTC P1516 is also set, diagnose that DTC first. A short between circuit 581 and 582 may have caused the ECM internal driver to overheat and set P1519.
If DTC P1519 is set, the ECM will default to 1 of the 2 limp home modes, random injector disable with engine speed limited to 1,800 RPM. The REDUCED POWER telltale will be illuminated and the ECM will remain in this condition for the entire ignition cycle even if the fault is corrected.
Make sure the ECM is bolted securely to the intake manifold. If DTC P1516 is not set and the ECM is secured correctly, replace the ECM. Refer to DTC P0601 in this section for reprogramming and ECM relearning instructions.
