Yamaha Fz1n Service Manual

FUEL INJECTION SYSTEM
8-37
EAS27350
ECU SELF-DIAGNOSTIC FUNCTION
The ECU is equipped with a self-diagnostic function in order to ensure that the fuel injection system 
is operating normally. If this function detects a malfunction in the system, it immediately operates the 
engine under substitute characteristics and illuminat es the engine trouble warning light to alert the 
rider that a malfunction has occurred in the syst em. Once a malfunction has been detected, a fault 
code is stored in the memory...

FUEL INJECTION SYSTEM
8-38
ET2D1027
SELF-DIAGNOSTIC FUNCTION TABLE
If the ECU detects an abnormal signal from a sensor while the vehicle is being driven, the ECU illu-
minates the engine trouble warning light and provides the engine with alternate operating instruc-
tions that are appropriate for the type of malfunction.
When an abnormal signal is received from a sensor, the ECU processes the specified values that 
are programmed for each sensor in order to provide the engine with alternate operating...

FUEL INJECTION SYSTEM
8-39
21Coolant temperature 
sensor
(open or short circuit) Coolant temperature sensor:
open or short circuit detected. Able Able
22 Intake air temperature 
sensor
(open or short circuit) Intake air temperature sensor:
open or short circuit detected. Able Able
23 Atmospheric pressure 
sensor
(open or short circuit) Atmospheric pressure sensor:
open or short circuit detected. Able Able
24 O
2 sensor No normal signal is received from the O2 
sensor. Able Able
30 Lean angle sensor...

FUEL INJECTION SYSTEM
8-40
Communication error with the meter39
Injector
(open circuit)
Injector:
open circuit detected. Able 
(depend- ing on 
the num- ber of faulty 
cylin- ders) Able 
(depend- ing on 
the num- ber of faulty 
cylin- ders)
41 Lean angle sensor
(open or short-circuit) Lean angle sensor:
open or short circuit detected.
Unable Unable
42 Speed sensor No normal signals are received from the 
speed sensor. Able Able
Neutral switch Neutral switch:
open or short circuit detected.
43 Fuel...

FUEL INJECTION SYSTEM
8-41
EAS27400
TROUBLESHOOTING METHOD
The engine operation is not normal and the
engine trouble warning light comes on.
1. Check: Fault code number
▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼▼
a. Check the fault code number displayed on  the meter.
b. Identify the faulty system with the fault 
code. Refer to “Self-Diagnostic Function 
table”.
c. Identify the probable cause of malfunction.  Refer to “Diagnostic code table”.
▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲▲
2. Checking and repair the probable cause...

FUEL INJECTION SYSTEM
8-42
If a malfunction is detected in the sensors 
or actuators, repair or replace all faulty 
parts.If no malfunction is detected in the sensors 
and actuators, check and repair inner parts 
of the engine.
EAS27420
DIAGNOSTIC MODE
Setting the diagnostic mode
1. Turn the main switch to “OFF” and set the engine stop switch to “ ”.
2. Disconnect the wire harness coupler from the fuel pump.
3. Press and hold the “SELECT” and “RESET” buttons
, turn the main switch to “ON”, and continue...

FUEL INJECTION SYSTEM
8-43
The data representing the operating conditions of the sensor appears on the odometer/tripme-
ter/fuel reserve tripmeter LCD.
 Actuator operation Set the engine stop switch to “ ” to operate the actuator.
NOTE:
If the engine stop switch is set to “ ”, set it to “ ”, and then set it to “ ” again.
9. Turn the main switch to “OFF” to cancel the diagnostic mode.
Fault code table
Fault code  No. Symptom Probable cause of malfunction
Diagnostic 
code No.
11  No normal signals are...

FUEL INJECTION SYSTEM
8-44
20When the main switch is 
turned to “ON”, the atmo-
spheric pressure sensor 
voltage and intake air pres-
sure sensor voltage differ 
greatly.  Atmospheric pressure sensor hose is 
clogged.
 Intake air pressure sensor hose is clogged, 
kinked, or pinched.
 Malfunction of the atmospheric pressure  sensor in the intermediate electrical poten-
tial.
 Malfunction of the intake air pressure sen- sor in the intermediate electrical potential.
 Malfunction in ECU. 02
03
21...

FUEL INJECTION SYSTEM
8-45
36Open circuit detected in the 
primary lead of the cylinder-
#4 ignition coil.  Open or short circuit in wire harness.
 Malfunction in ignition coil.
 Malfunction in a component of ignition cut-
off circuit system.
 Malfunction in ECU. 33
39 Open circuit detected in a 
injector.
 Open or short circuit sub-wire- harness.
 Open or short circuit in wire harness.
 Improperly installed injector.
 Defective injector. 36
37
38
39
41 Lean angle sensor: open or 
short circuit...

FUEL INJECTION SYSTEM
8-46
Sensor operation tableEr-2
No signals are received 
from the ECU within the 
specified duration.  Improper connection in wire harness.
 Malfunction in meter.
 Malfunction in ECU.
—
Er-3 Data from the ECU cannot 
be received correctly.  Improper connection in wire harness.
 Malfunction in meter.
 Malfunction in ECU. —
Er-4 Non-registered data has 
been received from the 
meter.  Improper connection in wire harness.
 Malfunction in meter.
 Malfunction in ECU.
—
Diag-...