Ecu Self-Diagnostic Function - Yamaha WR250F 2022 Owner's Service Manual

EAM30352

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 en-
gine under substitute characteristics and illuminates the engine trouble warning light to alert the rider
that a malfunction has occurred in the system. Once a malfunction has been detected, a fault code
number is stored in the memory of the ECU.
• To inform the rider that the fuel injection system is not functioning, the engine trouble warning light
flashes while the start switch is being pushed to start the engine.
• If a malfunction is detected in the system by the self-diagnostic function, the ECU provides an appro-
priate substitute characteristic operation, and alerts the rider of the detected malfunction by illuminat-
ing the engine trouble warning light.
Engine trouble warning light indication and fuel injection system operation
Warning light indication
Flashing*
Remains on
* The engine trouble warning light flashes when any one of the following conditions is present and the
start switch is pushed:
12: Crankshaft position sensor
Lean angle sensor
30:
(latch up detected)
Ignition coil
33: (Malfunction detected in the primary wire of
the ignition coil)
Checking the engine trouble warning light
The engine trouble warning light comes on for around 2 seconds when pushing the start switch.
a. Start switch is not being pushed.
b. Start switch is being pushed.
c. Engine trouble warning light goes off
d. Engine trouble warning light comes on for
around 2 seconds
ECU operation
Warning provided when
unable to start engine
Malfunction detected
a b
c
8-29
FUEL INJECTION SYSTEM
Fuel injection operation
Operation stopped
Operated with substitute
characteristics in accor-
dance with the descrip-
tion of the malfunction
Lean angle sensor
41:
(open or short circuit)
ECU internal malfunction
50:
(faulty ECU memory)
d c
Vehicle operation
Cannot be operated
Can or cannot be oper-
ated depending on the
fault code