ENGINE AND EMISSION CONTROL SYSTEM DESCRIPTION
EF & EC-21prose procedureExhaust Gas Sensor Heater Control section applies to catalyzer model only.
Exhaust Gas Sensor Heater Control (For catalyzer model)
INPUT/OUTPUT SIGNAL LINE
Exhaust Gas Sensor Heater Control - Input/Output Signal Line
Components (5)
Crank angle sensorAir flow meterEngine temperature sensorE.C.C.S. control unitExhaust gas sensor heater
Connections (4)
Crank angle sensor
Crank angle sensorE.C.C.S. control unit— Engine speed
Air flow meter
Air flow meterE.C.C.S. control unit— Amount of intake air
Engine temperature sensor
Engine temperature sensorE.C.C.S. control unit— Engine coolant temperature
E.C.C.S. control unit
E.C.C.S. control unitExhaust gas sensor heater
SYSTEM DESCRIPTION
The exhaust gas sensor heater helps activate the sensor quickly to stabilize closed-loop control under all operating conditions.
Fail-safe System
AIR FLOW METER MALFUNCTION
If the air flow meter output voltage is above or below the specified value, the E.C.U. senses an air flow meter malfunction. In case of a malfunction, the throttle sensor substitutes for the air flow meter. Though air flow meter is malfunctioning, it is possible to drive the vehicle and start the engine. But engine speed will not rise more than 2,000 rpm in order to inform the driver of fail-safe system operation while driving.
ENGINE TEMPERATURE SENSOR MALFUNCTION
When engine temperature sensor output voltage is below or above the specified value, engine temperature is fixed at the preset value as follows:
Engine Temperature Preset Value
Start
Engine temperature preset value °C (°F)20 (68)
Running
Engine temperature preset value °C (°F)80 (176)
Direct Ignition System
This system has no conventional distributor and high-tension wires. Small, very efficient ignition coils are fitted directly to each spark plug.
Direct Ignition System Schematic
Components (18)
Ignition switchE.C.C.S. relayBatteryTo starterE.C.U.Crank angle sensorPower transistor relayPower transistorIgnition coil No. 1Ignition coil No. 2Ignition coil No. 3Ignition coil No. 4Spark plug No. 1Spark plug No. 2Spark plug No. 3Spark plug No. 4Air flow meterEngine temperature sensor
Connections (17)
Ignition switch
Ignition switchE.C.C.S. relay
Ignition switchTo starter
E.C.C.S. relay
E.C.C.S. relayE.C.U.
Battery
BatteryE.C.C.S. relay
Crank angle sensor
Crank angle sensorE.C.U.— pins 43, 49, 16
E.C.U.
E.C.U.Power transistor— pins 1, 2, 3, 11
Power transistor relay
Power transistor relayPower transistor
Power transistor
Power transistorIgnition coil No. 1— No. 1
Power transistorIgnition coil No. 2— No. 2
Power transistorIgnition coil No. 3— No. 3
Power transistorIgnition coil No. 4— No. 4
Ignition coil No. 1
Ignition coil No. 1Spark plug No. 1— No. 1
Ignition coil No. 2
Ignition coil No. 2Spark plug No. 2— No. 2
Ignition coil No. 3
Ignition coil No. 3Spark plug No. 3— No. 3
Ignition coil No. 4
Ignition coil No. 4Spark plug No. 4— No. 4
Air flow meter
Air flow meterE.C.U.
Engine temperature sensor
Engine temperature sensorE.C.U.