Self Diagnosis Backups

OThe ECU takes the following measures to prevent engine damage when the DFI or the ignition system parts have troubles.

Service Codes

Parts

Output Signal Usable Range or Criteria

Backups by ECU

11

Main Throttle Sensor

Main Throttle Sensor Output Voltage 0.2 ~ 4.8 V

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 timing at closed throttle position and sets the DFI in the D-J method.

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 a-N method.

12

Inlet Air Pressure Sensor

Inlet Air Pressure (absolute)

Pv = 100 mmHg ~ 900 mmHg

If the inlet air pressure sensor system fails (the signal Pv is out of the usable range, wiring short or open), the ECU sets the DFI in the a - N method.

13

Inlet Air Temperature Sensor

Inlet Air Temperature Ta = - 47°C ~ + 178°C

If the inlet air temperature sensor fails (the signal is out of the usable range, wiring short or open), the ECU sets Ta at 40°C.

14

Water Temperature Sensor

Water Temperature Tw = - 30C° ~ + 120°C

If the water temperature sensor system fails (the signal is out of the usable range, wiring short or open), the ECU sets Tw at 80°C.

15

Atmospheric Pressure Sensor

Absolute Atmospheric Pressure

Pa = 100 mmHg ~ 900 mmHg

If the atmospheric pressure sensor system fails (the signal is out of the usable range, wiring short or open), the ECU sets Pa at 760 mmHg (the standard atmospheric pressure).

21

Crankshaft Sensor

Crankshaft sensor must send 23 signals (output signal) to the ECU at the one cranking.

If crankshaft sensor generates other than 23 signals, the engine stops by itself.

23

Camshaft Position Sensor

Cam sensor must send one signal (output signal) to the ECU at the two cranking

If the camshaft position sensor system fails (the signal is missing, wiring short or open), the ECU continues to ignite cylinders in the same sequence following the last good signal.

25

Speed Sensor

Speed sensor must send 4 signals (output signal) to the ECU at the one rotation of the engine sprocket.

The gear position is decided by the signal of the speed sensor.

If the speed sensor system fails (no signal, wiring short or open), the speedometer shows 0, and the ECU sets the top (6) gear position.

-down

Sensor

Vehicle-down Sensor Output Voltage (signal) Vd = 0.4 V ~ 4.4 V

If the vehicle-down sensor system has failures (the output voltage Vd is more than usable range, wiring open), the ECU shuts off the fuel pump, the fuel injectors and the ignition system.

32

Subthrottle sensor

Subthrottle Sensor Output Voltage 0.15 ~ 4.85 V

If the subthrottle sensor system fails (the signal is out of the usable range, wiring short or open), the actuator locks sub throttle valve at full open position.

Service Codes

Parts

Output Signal Usable Range or Criteria

Backups by ECU

51

Stick Coil #1 (Ignition Coil)*

The stick coil primary winding must send signals (output voltage) continuously to the ECU.

If the ignition primary winding #1 has failures (no signal, wiring short or open), the ECU shuts off the injector #1 to stop fuel to the cylinder #1, though the engine keeps running.

52

Stick Coil #2 (Ignition Coil)*

The stick coil primary winding must send signals (output voltage) continuously to the ECU.

If the ignition primary winding #2 has failures (no signal, wiring short or open), the ECU shuts off the injector #2 to stop fuel to the cylinder #2, though the engine keeps running.

53

Stick Coil #3 (Ignition Coil)*

The stick coil primary winding must send signals (output voltage) continuously to the ECU.

If the ignition primary winding #3 has failures (no signal, wiring short or open), the ECU shuts off the injector #3 to stop fuel to the cylinder #3, though the engine keeps running.

54

Stick Coil #4 (Ignition Coil) *

The stick coil primary winding must send signals (output voltage) continuously to the ECU.

If the ignition primary winding #4 has failures (no signal, wiring short or open), the ECU shuts off the injector #4 to stop fuel to the cylinder #4, though the engine keeps running.

Valve Actuator

The actuator operates open and close of the subthrottle valve by the pulse signal from the ECU.

If the subthrottle valve actuator fails (the signal is out of the usable range, wiring short or open), the ECU stops the current to the actuator.

Note:

(1) D-J Method and a - N Method: When the engine load is light like at idling or low speed, the ECU determines the injection quantity by calculating from the throttle vacuum (inlet air pressure sensor output voltage) and engine speed (crankshaft sensor output voltage). This method is called D-J method (low-speed mode). As the engine speed increases, and the engine load turns middle to heavy, the ECU determines the injection quantity by calculating from the throttle opening (throttle sensor output voltage) and the engine speed. This method is called a - N method (high-speed mode).

(*) This depends on the number of stopped cylinders.

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