Backups

Service

Parts

Output Signal Usable

Backups by ECU

Codes

Range or Criteria

If the main throttle sensor system fails (the signal

is out of the usable range, wiring short or open),

the ECU locks ignition timing into the ignition

11

Main

Main Throttle Sensor

timing at closed throttle position and sets the DFI

Throttle

Output Voltage

in the D-J method.

Sensor

0.2 4.8 V

Also, the main throttle sensor system and inlet air

pressure fails, the ECU locks ignition timing into

the ignition timing at closed throttle position and

sets the DFI in the α-N method.

Inlet Air

Inlet Air Pressure

If the inlet air pressure sensor system fails (the

12

(absolute)

signal Pv is out of the usable range, wiring short

Pressure

Pv = 100 mmHg ~ 900

or open), the ECU sets the DFI in the α - N

Sensor

mmHg

method.

13

Inlet Air

Inlet Air Temperature

If the inlet air temperature sensor fails (the signal

Tempera-

is out of the usable range, wiring short or open),

Ta = –47°C +178°C

ture Sensor

the ECU sets Ta at 40°C.

14

Water Tem-

Water Temperature

If the water temperature sensor system fails (the

perature

Tw = –30C° +120°C

signal is out of the usable range, wiring short or

Sensor

open), the ECU sets Tw at 80°C.

Atmo-

Absolute Atmospheric

If the atmospheric pressure sensor system fails

15

spheric

Pressure

(the signal is out of the usable range, wiring short

Pressure

Pa = 100 mmHg 900

or open), the ECU sets Pa at 760 mmHg (the

Sensor

mmHg

standard atmospheric pressure).

Crankshaft sensor must

21

Crankshaft

send 23 signals (output

If crankshaft sensor generates other than 23

Sensor

signal) to the ECU at the

signals, the engine stops by itself.

one cranking.

Camshaft

Cam sensor must send

If the camshaft position sensor system fails

23

one signal (output signal)

(the signal is missing, wiring short or open), the

Position

to the ECU at the two

ECU continues to ignite cylinders in the same

Sensor

cranking

sequence following the last good signal.

Speed sensor must send

4 signals (output signal)

24

to the ECU at the one

If the speed sensor system fails (no signal, wiring

Speed

rotation of the engine

and

short or open), the speedometer shows 0, and

Sensor

sprocket.

25

the ECU sets the top (6) gear position.

The gear position is

decided by the signal of

the speed sensor.

Vehicle

Vehicle-down Sensor

If the vehicle-down sensor system has failures

31

(the output voltage Vd is more than usable range,

-down

Output Voltage (signal)

wiring open), the ECU shuts off the fuel pump,

Sensor

Vd = 0.4 V 4.4 V

the fuel injectors and the ignition system.

FUEL SYSTEM (DFI) 3-39

Self-Diagnosis

Service

Parts

Output Signal Usable

Backups by ECU

Codes

Range or Criteria

Subthrottle Sensor

If the subthrottle sensor system fails (the signal

32

Subthrottle

is out of the usable range, wiring short or open),

Output Voltage

sensor

0.15 4.85 V

the actuator locks sub throttle valve at full open

position.

Stick Coil

The stick coil primary

If the ignition primary winding #1 has failures (no

51

winding must send

signal, wiring short or open), the ECU shuts off

#1 (Ignition

signals (output voltage)

the injector #1 to stop fuel to the cylinder #1,

Coil)*

continuously to the ECU.

though the engine keeps running.

Stick Coil

The stick coil primary

If the ignition primary winding #2 has failures (no

52

winding must send

signal, wiring short or open), the ECU shuts off

#2 (Ignition

signals (output voltage)

the injector #2 to stop fuel to the cylinder #2,

Coil)*

continuously to the ECU.

though the engine keeps running.

Stick Coil

The stick coil primary

If the ignition primary winding #3 has failures (no

53

winding must send

signal, wiring short or open), the ECU shuts off

#3 (Ignition

signals (output voltage)

the injector #3 to stop fuel to the cylinder #3,

Coil)*

continuously to the ECU.

though the engine keeps running.

Stick Coil

The stick coil primary

If the ignition primary winding #4 has failures (no

54

winding must send

signal, wiring short or open), the ECU shuts off

#4 (Ignition

signals (output voltage)

the injector #4 to stop fuel to the cylinder #4,

Coil) *

continuously to the ECU.

though the engine keeps running.

The actuator operates

62

Subthrottle

open and close of the

If the subthrottle valve actuator fails (the signal is

Valve

subthrottle valve by the

out of the usable range, wiring short or open), the

Actuator

pulse signal from the

ECU stops the current to the actuator.

ECU.