Electric Throttle
The Powertrain Control Module (PCM) uses the electric throttle to regulate engine torque.
The electric throttle is located between the clean air duct and the supercharger.
For additional information, refer to: INTAKE AIR DISTRIBUTION AND FILTERING
The throttle butterfly valve is operated by an electric Direct Current (DC) motor integrated into the throttle body. The PCM uses a Pulse Width Modulation (PWM) signal to control the DC motor. The PCM compares the Accelerator Pedal Position (APP) sensor inputs against an electronic map to determine the required position of the throttle butterfly valve. The PCM and electric throttle are also required to:
- Monitor requests for cruise control operation.
- Automatically operate the electric throttle for accurate cruise control.
- Implement all dynamic stability control engine interventions.
- Monitor and implement maximum engine speed and road speed cut outs.
- Provide different engine maps for the ride and handling optimization system.
A software strategy within the PCM calibrates the position of the throttle butterfly valve at the beginning of each ignition cycle. When the ignition is turned ON (Power Mode 6), the PCM does a self test and calibration routine. The PCM fully closes the throttle butterfly valve and then opens it again. This tests the default position springs and allows the PCM to learn the fully closed position.
Throttle Position Sensor
The Throttle Position Sensor (TPS) allows the PCM to determine the position and angular rate of change of the throttle butterfly valve.
There are 2 TPS located in the electric throttle.
If a TPS fails, the PCM:
- Adopts a limp home mode where engine speed is limited to a maximum of approximately 2, 000 Revolutions Per Minute (RPM).
- Discontinues evaporative emissions control.
- Discontinues closed loop control of engine idle speed.
If the TPS fails, the engine will suffer from poor running and throttle response.