Yamaha YZF-R25, Service Manual

Page: 396 / 456

FUEL INJECTION SYSTEM
8-51
Fault code No. 39
Fault code No. 39
Item Fuel injector: open or short circuit detected.
Fail-safe system
Able to start engine (depending on the number of faulty cylinders)
Able to drive vehicle (depending on the number of faulty cylinders)
Diagnostic code No. 36, 37
36
Actuation
Actuates fuel injector #1 five times at one-second intervals.
The “CHECK” indicator and “
” on the Yamaha diagnostic tool screen
comes on each time the fuel injector is actuated.
Procedure
Disconnect the fuel pump coupler, and then check that fuel injector #1 is
actuated five times by listening for the operating sound.
37
Actuation
Actuates fuel injector #2 five times at one-second intervals.
The “CHECK” indicator and “
” on the Yamaha diagnostic tool screen
comes on each time the fuel injector is actuated.
Procedure
Disconnect the fuel pump coupler, and then check that fuel injector #2 is
actuated five times by listening for the operating sound.
Item
Probable cause of malfunc-
tion and check
Maintenance job
Confirmation of service com-
pletion
1 Identify the malfunctioning fuel
injector Execute the diagnostic mode.
(Code Nos. 36, 37)
Identify the fuel injector that
does not produce an operating
sound.
Perform the following proce-
dures for the defective fuel injec-
tor.
2 Connection of fuel injector #1
and/or fuel injector #2 coupler.
Check the locking condition of
the coupler.
Disconnect the coupler and
check the pins (bent or broken
terminals and locking condition
of the pins). Improperly connected
→
Con-
nect the coupler securely or re-
place the wire harness.
Execute the diagnostic mode.
(Code Nos. 36, 37)
No operating sound
→
Go to
item 3.
Operating sound
→
Go to item
7.
3 Defective fuel injector #1 and/or
fuel injector #2. Measure the fuel injector resis-
tance.
Replace if out of specification.
Refer to “CHECKING THE
FUEL INJECTORS” on page
8-94. Execute the diagnostic mode.
(Code Nos. 36, 37)
No operating sound
→
Go to
item 4.
Operating sound
→
Go to item
7.
4 Connection of ECU coupler.
Check the locking condition of
the coupler.
Disconnect the coupler and
check the pins (bent or broken
terminals and locking condition
of the pins). Improperly connected
→
Con-
nect the coupler securely or re-
place the wire harness.
Execute the diagnostic mode.
(Code Nos. 36, 37)
No operating sound
→
Go to
item 5.
Operating sound
→
Go to item
7.