FUNCTION OF MAIN COMPONENTS
The main components of the engine control system are as follows:
| Component | Outline | Quantity | Function |
|---|---|---|---|
| ECM | 16-bit CPU | 1 | The ECM effects overall control of the engine control system to suit the operating conditions of the engine in accordance with the signals provided by the sensors. |
| Air Pressure Sensor | Semiconductor Silicon Chip Type | 1 | This sensor uses built-in semiconductors to detect the intake manifold pressure. |
| Intake Air Temperature Sensor | Thermistor Type | 1 | This sensor detects the intake air temperature by means of an internal thermistor. |
| Crank Position Sensor (Rotor Teeth/1) |
Pick-up Coil Type | 1 | This sensor detects the engine speed and performs the cylinder identification. |
| Accelerator Pedal Sensor Assembly | Non-contact Type | 1 | This sensor detects the amount of pedal effort applied to the accelerator pedal. |
| Engine Coolant Temperature Sensor | Thermistor Type | 1 | This sensor detects the engine coolant temperature by means of an internal thermistor. |
| Engine Speed Sensor (Rotor Teeth/56-8) |
Pick-up Coil Type | 1 | This sensor is attached to the roller ring in the injection pump to detect the engine speed. |
| Spill Control Valve | Solenoid Valve Type | 1 | This valve controls the fuel injection volume in accordance with the signals received from the ECM. |
| Timing Control Valve | Duty Solenoid Type | 1 | This valve controls the fuel injection timing based on signals from the ECM. |
| Fuel Temperature Sensor | Thermistor Type | 1 | This sensor detects the fuel temperature in the injection pump by means of an internal thermistor. |
SYSTEM CONTROL
The engine control system has the following features. The ECM controls these systems.
| System | Outline |
|---|---|
| Fuel Injection Volume Control | Based on the signals received from the sensors, the ECM determines the fuel injection volume in accordance with the engine condition. |
| Fuel Injection Timing Control | Based on the signals received from the sensors, the ECM determines the fuel injection timing in accordance with the engine condition. |
| Idle Speed Control | The ECM determines the idle speed in accordance with the engine condition, and controls the fuel injection volume in order to maintain the target idle speed. |
| Glow Plug Control | Controls the length of time when the current is applied to the glow plugs, in accordance with engine coolant temperature. |
| Diesel Throttle Control | Fully closes the diesel throttle valve in order to reduce the vibration when the engine is stopped. |
| Air Conditioning Cut-off Control* | By controlling the air conditioning compressor on or off in accordance with the engine condition, driveability is maintained. |
| Brake Override System | The driving torque is restricted when both the accelerator and brake pedals are depressed. (For the activation conditions and inspection method, refer to the Repair Manual.) |
| Diagnosis | When the ECM detects a malfunction, it diagnoses and memorizes the failed section. |
| Fail-safe | When the ECM detects a malfunction, it stops or controls the engine in accordance with the data already stored in the memory. |
*: Models with air conditioning system