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FUEL SYSTEM (DFI) 3-39
Self-Diagnosis
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,
thou
gh 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
Coi
l) *
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.
62
Subthrottle
Valve
Actuator
The
actuator operates
open and close of the
subthrottle valve by the
pu
lse signal from the
ECU.
If the subthrottle valve actuator fails (the signal is
out of the usable range, w iring short or open), the
ECU stops the current to the actuator.
Note:
(1) D-J Method and α – N Method: When the engine load is light like at idling or l ow 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 α – N method (high-speed
mode).
(*) This depends on the number of stopped cylinders.