Ecu Self-Diagnostic Function - Yamaha XT660R S Service Manual

EAS00899

ECU SELF-DIAGNOSTIC FUNCTION

The ECU is equipped with a self-diagnostic function to ensure the normal operation of the fuel injec-
tion system. If a malfunction is detected in the fuel injection system, the self-diagnostic function
immediately operates the engine with alternate operating instructions and the engine trouble warn-
ing light comes on to alert the rider of the malfunction. Once a malfunction has been detected, its
corresponding fault code is stored in the memory of the ECU.
• To alert the rider that the fuel injection system is not functioning, the engine trouble warning light
flashes when the start switch is pushed to start the engine.
• If a malfunction is detected in the fuel injection system, the ECU provides the proper alternate
operating instructions necessary to operate the engine and the engine trouble warning light
comes on to alert the rider of the malfunction.
• After the engine has been turned off, the lowest fault code appears on the odometer/fuel reserve
tripmeter/tripmeter 2 LCD. Once a fault code has been displayed, it remains stored in the mem-
ory of the ECU until it is deleted.
EAS00900
Engine trouble warning light indication and FI system operation
Engine trouble
warning light
Flashes*
Remains on
* The warning light flashes if any one of the following conditions is present and the start switch is
pushed:
12: Crankshaft position sensor
19: Sidestand switch
(open circuit in the wire to the ECU)
30: Lean angle cut-off switch
(latch up detected)
FUEL INJECTION SYSTEM
ECU operation
Warning provided
when unable to start
engine
Malfunction detected
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FI operation
Operation stopped
Operated with alter-
nate characteristics in
accordance with the
description of the mal-
function
41: Lean angle cut-off switch
(open or short circuit)
50: ECU internal malfunction
(faulty ECU memory)
7 - 3
FI
Vehicle operation
Cannot be operated
Can or cannot be
operated depending
on the fault code