Ecu Self-Diagnostic Function - Yamaha YXR70FX Service Manual

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 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.
1 Engine trouble warning light
Engine trouble warning light indication and fuel injection system operation
Warning light indi-
cation
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
Lean angle sensor
30:
(latch up detected)
FUEL INJECTION SYSTEM
1
ECU operation
Warning provided
when unable to start
engine
Malfunction detected
6 - 4
• To inform the rider that the fuel injection sys-
tem 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 pro-
vides an appropriate substitute characteristic
operation, and alerts the rider of the detected
malfunction by illuminating the engine trou-
ble warning light.
• After the engine has been stopped, the low-
est fault code number appears on the odom-
eter/tripmeter LCD. Once a fault code has
been displayed, it remains stored in the
memory of the ECU until it is deleted.
Fuel injection opera-
tion
Operation stopped
Operated with substi-
tute characteristics in
accordance with the
description of the mal-
function
Lean angle sensor
41:
(open or short-circuit)
ECU internal malfunction
50:
(memory check error)
FI
Vehicle operation
Cannot be operated
Can or cannot be
operated depending
on the fault code