Yamaha RST90GTY, Service Manual

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49
FI
FUEL INJECTION SYSTEM
ECU SELF-DIAGNOSTIC FUNCTION
The ECU is equipped with a self-diagnostic function in order to ensure that the fuel injection system is operat-
ing normally. If this function detects a malfunction in the system, it immediately operates the engine under
substitute characteristics and the warning light and self-diagnostic warning indicator on the upper LCD flash to
alert the rider that a malfunction has occurred in the system. Once a malfunction has been detected, a fault
code is stored in the memory of the ECU.
• If a malfunction is detected in the system by the self-diagnostic function, the ECU provides an appropriate
substitute characteristic operation, and the warning light and self-diagnostic warning indicator on the upper
LCD flash to alert the rider of the detected malfunction.
• The lowest fault code number appears on the lower LCD. Once a fault code has been displayed, it remains
stored in the memory of the ECU until it is deleted.
SELF-DIAGNOSTIC FUNCTION TABLE
If the ECU detects an abnormal signal from a sensor while the snowmobile is being driven, the warning light
and self-diagnostic warning indicator on the upper LCD flash to alert the rider that a malfunction has occurred
and the ECU provides the engine with alternate operating instructions that are appropriate for the type of mal-
function.
When an abnormal signal is received from a sensor, the ECU processes the specified values that are pro-
grammed for each sensor in order to provide the engine with alternate operating instructions that enable the
engine to continue to operate or stop operating, depending on the conditions.
Self-Diagnostic-Function table
Fault code
No.
Item Symptom
Able/unable
to start
Able/unable
to drive
12
Crankshaft position sensor No normal signals are received from the
crankshaft position sensor.
Unable Unable
13
Intake air pressure sensor 1 (cylinders #1,
#2, and #3) (open or short circuit) Intake air pressure sensor 1 (cylinders #1,
#2, and #3): open or short circuit detected.
Able Able
14
Intake air pressure sensor 1 (cylinders #1,
#2, and #3) (hose line) Intake air pressure sensor 1 (cylinders #1,
#2, and #3): hose system malfunction
(clogged or detached hose).
Able Able
15
Throttle position sensor (open or short cir-
cuit) Throttle position sensor: open or short cir-
cuit detected.
Able Able
16 Throttle position sensor (stuck) Stuck throttle position sensor detected. Able Able
21
Coolant temperature sensor Coolant temperature sensor: open or short
circuit detected.
Able Able
22
Intake air temperature sensor Intake air temperature sensor: open or
short circuit detected.
Able Able
25
Intake air pressure sensor 2 (cylinder #1)
(open or short circuit) Intake air pressure sensor 2 (cylinder #1):
open or short circuit detected.
Able Able
26
Intake air pressure sensor 2 (cylinder #1)
(hose line) Intake air pressure sensor 2 (cylinder #1):
hose system malfunction (clogged or
detached hose).
Able Able
30
Oil pressure dropped Engine stops when an oil pressure drop is
detected.
Unable Unable
33
Cylinder-#1 ignition coil (faulty ignition) Malfunction detected in the primary lead of
the cylinder-#1 ignition coil. Able
(depending
on the num-
ber of faulty
cylinders)
Able
(depending
on the num-
ber of faulty
cylinders)
34
Cylinder-#2 ignition coil (faulty ignition) Malfunction detected in the primary lead of
the cylinder-#2 ignition coil. Able
(depending
on the num-
ber of faulty
cylinders)
Able
(depending
on the num-
ber of faulty
cylinders)