THEORY OF OPERATION
The Electronic Throttle Control (ETC) system uses two Accelerator Pedal Position (APP) sensors to monitor the accelerator pedal position. The APP sensors 1 and 2 are located within the pedal assembly. Each sensor has a 5-volt reference circuit, a low reference circuit, and a signal circuit. Processors are also used to monitor the ETC system data. The processors are located within the Powertrain Control Module (PCM). Each signal circuit provides processors with a signal voltage proportional to pedal movement. The processors share and monitor data to verify that the indicated APP calculation is correct.
The Oxygen sensors (O2 sensor) are used for fuel control and catalyst monitoring. Each O2 sensor compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the Powertrain Control Module (PCM) operates in an Open Loop mode, ignoring the O2 sensor signal voltage while calculating the air-to-fuel ratio. The heating elements inside each O2 sensor heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed Loop earlier and the PCM to calculate the air-to-fuel ratio sooner. While the engine runs, the O2 sensor heats up and begins to generate a voltage within a range of 0-1, 275 mV. Once sufficient O2 sensor voltage fluctuation is observed by the PCM, Closed Loop is entered. The PCM uses the O2 sensor voltage to determine the air-to-fuel ratio. An O2 sensor voltage that increases toward 1, 000 mV indicates a rich fuel mixture. An O2 sensor voltage that decreases toward 0 mV indicates a lean fuel mixture.
The Oxygen sensors (O2 sensor) are used for fuel control and catalyst monitoring. Each O2 sensor compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the Powertrain Control Module (PCM) operates in an Open Loop mode, ignoring the O2 sensor signal voltage while calculating the air-to-fuel ratio. The heating elements inside each O2 sensor heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed Loop earlier and the PCM to calculate the air-to-fuel ratio sooner. While the engine runs, the O2 sensor heats up and begins to generate a voltage within a range of 0-1, 275 mV. Once sufficient O2 sensor voltage fluctuation is observed by the PCM, Closed Loop is entered. The PCM uses the O2 sensor voltage to determine the air-to-fuel ratio. An O2 sensor voltage that increases toward 1, 000 mV indicates a rich fuel mixture. An O2 sensor voltage that decreases toward 0 mV indicates a lean fuel mixture.
For 20 seconds following a vehicle cold start, the air injection system delivers a controlled amount of outside air into the exhaust system, upstream of the catalytic converters, in order to help reduce hydrocarbon and carbon monoxide gas emissions.
For 20 seconds following a vehicle cold start, the air injection system delivers a controlled amount of outside air into the exhaust system, upstream of the catalytic converters, in order to help reduce hydrocarbon and carbon monoxide gas emissions.
The fuel level signal is a direct input to the Cluster. The fuel level signal is sent to the Totally Integrated Power Module (TIPM) over the CAN B bus circuit. The Powertrain Control Module (PCM) receives the fuel level signal from the TIPM over the CAN C bus circuit.
The ambient temperature sensor signal is a direct input to the Totally Integrated Power Module (TIPM). The TIPM sends the Powertrain Control Module (PCM) the ambient temperature signal over the CAN C bus.
The Powertrain Control Module (PCM) receives the vehicle speed signal over the CAN C bus from the Anti-lock Brake Module.
The A/C Pressure Transducer signal is a direct input to the Totally Integrated Power Module (TIPM). The TIPM sends the Powertrain Control Module (PCM) the A/C pressure signal over the CAN C bus.
The Powertrain Control Module (PCM) receives the vehicle speed signal over the CAN C bus from the Anti-lock Brake Module.
The Totally Integrated Power Module (TIPM) receives a fuel level signal over CAN B from the Cluster. The TIPM transmits the fuel level message to the PCM over the CAN C bus.
The ABS Module sends vehicle speed information over the CAN C Bus circuit to the Powertrain Control Module (PCM).
The Anti-Lock Brake (ABS) Module sends an implausible distance signal over the CAN C Bus circuit to the Powertrain Control Module (PCM).
The ABS Module sends an implausible distance signal over the CAN C Bus circuit to the Powertrain Control Module (PCM).