Circuit Operation

SYSTEM OUTLINE

This system utilizes an engine control module and maintains overall control of the engine, transmission and so on. An outline of the engine control is explained here.

1. INPUT SIGNALS

1. Engine coolant temperature signal circuit
The engine coolant temperature sensor detects the engine coolant temperature and has a built-in thermistor with a resistance which varies according to the engine coolant temperature thus the engine coolant temperature is input in the form of a control signal into TERMINAL THW of the engine control module.

2. Intake air temperature signal circuit
The intake air temperature sensor detects the intake air temperature, which is input as a control signal into TERMINAL THA of the engine control module.

3. Oxygen sensor signal circuit
The oxygen density in the exhaust gases is detected and input as a control signal into TERMINAL OX1B of the engine control module.

4. RPM signal circuit
Camshaft position and crankshaft position are detected by the camshaft position sensor and crankshaft position sensor. Camshaft position is input as a control signal to TERMINAL G22+ of the engine control module, and engine RPM is input into TERMINAL NE+.

5. Throttle signal circuit
The throttle control motor detects the throttle valve opening angle, which is input as a control signal into TERMINAL VTA of the engine control module.

6. Vehicle speed signal circuit
The vehicle speed sensor, installed inside the transmission, detects the vehicle speed and inputs a control signal into TERMINAL SPD of the engine control module.

7. Park/Neutral position SW signal circuit (A/T)
The Park/Neutral position SW detects whether the shift position are in neutral, parking or not, and inputs a control signal into TERMINAL STA of the engine control module.

8. A/C SW signal circuit
The A/C amplifier function is built in the engine control module. The A/C SW signal inputs into the TERMINAL A/CS of the engine control module.

9. 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 engine control module start-up power supply is applied to TERMINAL +B of engine control module via EFI relay.

10. Intake air volume signal circuit
Intake air volume is detected by the mass airflow meter and a signal is input into TERMINAL VG of the engine control module as a control signal.

11. NSW signal circuit
To confirm whether the engine is cranking, the voltage applied to the starter motor during cranking is detected and the signal is input into TERMINAL NSW of the engine control module as a control signal.

12. Engine knock signal circuit
Engine knocking is detected by knock sensor and the signal is input into TERMINAL KNK1 as a control signal.

13. Air fuel ratio signal circuit
The air fuel ratio is detected and input as a control signal into TERMINAL AF1A+ of the engine control module.

2. CONTROL SYSTEM
- SFI system
The SFI system monitors the engine condition through the signals, which are input from each sensor (Input signals from (1) to (13) etc.) to the engine control module. The best fuel injection volume is decided based on this data and the program memorized by the engine control module, and the control signal is output to TERMINALS #10, #20, #30 and #40 of the engine control module to operate the injector. (Inject the fuel). The SFI system produces control of fuel injection operation by the engine control module in response to the driving conditions.

- ESA system
The ESA system monitors the engine condition through the signals, which are input to the engine control module from each sensor (Input signals from (1), (2), (4) to (12) etc.) the best ignition timing is detected according to this data and the memorized data in the engine control module, and the control signal is output to TERMINALS IGT1, IGT2, IGT3 and IGT4. This signal controls the igniter to provide the best ignition timing for the driving conditions.

- Fuel pump control system
The engine control module operation outputs to TERMINAL FC and controls the CIR OPN relay. Thus controls the fuel pump drive speed in response to conditions.

3. DIAGNOSIS SYSTEM
With the diagnosis system, when there is a malfunctioning in the engine control module signal system, the malfunction system is recorded in the memory.

4. FAIL-SAFE SYSTEM
When a malfunction occurs in any systems, if there is a possibility of engine trouble being caused by continued control based on the signals from that system, the fail-safe system either controls the system by using data (Standard values) recorded in the engine control module memory or else stops the engine.