Ecu (Engine) Self-Diagnostic Function - Yamaha XP500 Service Manual

EAS00899

ECU (engine) SELF-DIAGNOSTIC FUNCTION

The ECU (engine) is equipped with a self-diagnostic function in order to ensure that the fuel injec-
tion system is operating normally. If this function detects a malfunction in the system, it immediately
operates the engine 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 is stored in the memory of the ECU (engine).
• To inform the rider that the fuel injection system is not functioning, the engine trouble warning
light flashes when 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 (engine) pro-
vides an appropriate substitute characteristic operation, and alerts the rider of the detected mal-
function by illuminating the engine trouble warning light.
• After the engine has been stopped, the lowest fault code number appears on the clock LCD.
Once a fault code has been displayed, it remains stored in the memory of the ECU (engine) until
it is deleted.
EAS00900
Engine trouble warning light indication and FI system operation
Warning light
indication
Flashing*
Remains ON
* The warning light flashes when any one of the conditions listed below is present and the start
switch is pushed:
12: Crankshaft position sensor
19: Sidestand switch
(open circuit in the wire to the ECU
(engine))
30: Lean angle cut-off switch
(latch up detected)
FUEL INJECTION SYSTEM
ECU (engine) opera-
tion
Warning provided
when unable to start
engine
Malfunction detected
FI operation
Operation stopped
Operated with substi-
tute characteristics in
accordance with the
description of the mal-
function.
41: Lean angle cut-off switch
(open or short-circuit)
50: ECU (engine) internal malfunction
(faulty ECU (engine) memory)
7 - 3
FI
Vehicle operation
Can not be operated
Can or cannot be
operated depending
on the fault code