4-20 FI SYSTEM DIAGNOSIS
FAIL-SAFE FUNCTION
FI system is provided with fail-safe function to allow the engine to start and the motorcycle to run in a mini-
mum performance necessary even under malfunction condition.
The engine can start and can run even if the above signal is not received from each sensor. But, the engine
running condition is not complete, providing only emergency help (by fail-safe circuit). In this case, it is nec-
essary to bring the motorcycle to the workshop for complete repair.
When two ignition signals or two injector signals are not received by ECM, the fail-safe circuit can not work
and ignition/injection is stopped.
ITEM
FAIL-SAFE MODE
STARTING
ABILITY
RUNNING
ABILITY
IAP sensor
Intake air pressure is fixed to 101
kPa (760 mmHg).
“YES”
“YES”
TP sensor
The throttle opening is fixed to full
open position.
Ignition timing is also fixed.
“YES”
“YES”
ECT sensor
Engine coolant temperature value is
fixed to 80 °C (176 °F).
Cooling fan is fixed on position.
“YES”
“YES”
IAT sensor
Intake air temperature value is fixed
to 40 °C (104 °F).
“YES”
“YES”
Ignition signal
#1 fuel-cut
“YES”
“YES”
#2 cylinder can run.
#2 fuel-cut
“YES”
“YES”
#1 cylinder can run.
Injection signal
—
“YES”
“YES”
#2 cylinder can run.
—
“YES”
“YES”
#1 cylinder can run.
Gear position signal
Gear position signal is fixed to 6th
gear.
“YES”
“YES”
HO2 sensor
Feedback compensation is inhibited.
(Air/fuel ratio is fixed to normal.)
“YES”
“YES”
PAIR control solenoid valve
ECM stops controlling PAIR control
solenoid valve.
“YES”
“YES”
ISC valve
When motor disconnection or lock
occurs, power from ECM is shut off.
“YES”
“YES”
