Ecu Self-Diagnostic Function - Yamaha 2009 XP500Y TMAX Service Manual

EAS27350

ECU SELF-DIAGNOSTIC FUNCTION

The ECU (engine control unit) 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 (engine control unit).
• 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 control unit)
provides 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 control unit) until
it is deleted.
Engine trouble warning light indication and FI system operation
Warning light indica-
tion
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
Sidestand switch
19: (open circuit in the wire to the ECU (en-
gine control unit))
Lean angle sensor
30:
(latch up detected)
Checking for a defective engine trouble warning light bulb
The engine trouble warning light comes on for 1.4 seconds after the main switch has been turned to
"ON" and when the start switch is being pushed. If the warning light does not come on under these con-
ditions, the warning light bulb may be defective.
ECU (engine control
unit) operation
Warning provided
when unable to start
engine
Malfunction detected
8-31
FUEL INJECTION SYSTEM
FI operation
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 (engine control unit) internal
malfunction
50:
(faulty ECU (engine control unit)
memory)
Vehicle operation
Cannot be operated
Can or cannot be oper-
ated depending on the
fault code