System Outline
The engine control system utilizes a microcomputer and maintains overall control of the engine, transmission and so on. An outline of the engine control system is explained here.
- Input Signals
- Engine coolant temp. signal circuit
The engine coolant temp. sensor detects the engine coolant temperature and has a built-in thermistor whose resistance varies according to the engine coolant temperature. The engine coolant temperature is input into TERMINAL THW of the engine control module as a control signal.
- Intake air temp. signal circuit
The inlet air temp. sensor is installed in the air flow meter and detects the intake air temperature, which is input as a control signal to TERMINAL THA of the engine control module.
- Oxygen sensor signal circuit
The oxygen density in the exhaust emissions is detected and is input as a control signal from the heated oxygen sensors to TERMINALS OX1B and OX2B of the engine control module.
- RPM signal circuit
The engine RPM is detected by the crankshaft position sensor which is installed in the cylinder block and the signal is input into TERMINAL NE+ of the engine control module as a control signal.
- Throttle position sensor signal circuit
The throttle position sensor detects the throttle valve opening angle as a control signal, which is input into TERMINALS VTA1 and VTA2 of the engine control module.
- Vehicle speed circuit
The vehicle speed sensor detects the vehicle speed, and the signal is input into TERMINAL SPD of the engine control module via the combination meter, from TERMINAL SP1 of the skid control ECU with actuator.
- Battery signal circuit
Voltage is constantly applied to TERMINAL BATT of the engine control module. When the ignition SW is turned on, the voltage for the engine control module start up power supply is applied through the EFI relay to TERMINALS +B and +B2 of the engine control module via the EFI MAIN relay.
- Intake air volume signal circuit
The intake air volume is detected by the mass air flow meter, and is input as a control signal to TERMINAL VG of the engine control module.
- Stop lamp SW signal circuit
The stop lamp SW is used to detect whether the vehicle is braking or not, and the signal is input into TERMINAL STP of the engine control module as a control signal.
- Starter signal circuit
To confirm whether the engine is cranking, the voltage which is being applied to the starter motor when the engine is cranking is detected, and is input into TERMINAL STA of the engine control module as a control signal.
- Engine knock signal circuit
Engine knocking is detected by the knock sensors, and is input into TERMINALS KNK1 and KNK2 of the engine control module as a control signal.
- Air fuel ratio signal circuit
The air fuel ratio is detected and input as a control signal into TERMINALS A1A+, A2A+ of the engine control module.
- Engine coolant temp. signal circuit
- Control System
* SFI system
The SFI system optimizes the fuel injection levels by adjusting and correcting the basic timing calculated for the engine conditions, in accordance with sensor signals.
* ESA system
The ESA system optimizes the ignition by adjusting and correcting the basic timing calculated for the engine conditions, in accordance with sensor signals.
* ETCS-i
The ETCS-I optimizes the throttle opening by adjusting and correcting the basic opening calculated for the engine conditions, in accordance with sensor signals.
* Dual VVT-i
Dual VVT-i optimizes the intake and exhaust valve timing in accordance with the engine conditions.
- Diagnosis System
When there is a malfunction in the engine control module signal system, the malfunctioning system is recorded in the memory. The malfunctioning system can be found by reading the code displayed on the malfunction indicator lamp.
- Fail-Safe System
When a malfunction has occurred in any system, there is a possibility of causing engine trouble due to continued control based on that system. In that case, the fail-safe system either controls the system using the data (Standard values) recorded in the engine control module memory, or else stops the engine.