Ecu Self-Diagnostic Function; Fail-Safe Actions (Substitute Characteristics Operation Control) - Yamaha 2009 Diversion XJ6S Service Manual

EAS27350

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 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
G
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 provides an appro-
G
priate substitute characteristic operation, and alerts the rider of the detected malfunction by illuminat-
ing the engine trouble warning light.
After the engine has been stopped, the lowest fault code number appears on the clock LCD. Once a
G
fault code has been displayed, it remains stored in the memory of the ECU until it is deleted.
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
Sidestand switch
19:
(open circuit in the wire to the ECU)
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.
a. Main switch "OFF"
b. Main switch "ON"
c. Engine trouble warning light off
EAS27362

FAIL-SAFE ACTIONS (SUBSTITUTE CHARACTERISTICS OPERATION CONTROL)

If the ECU detects an abnormal signal from a sensor while the vehicle is being driven, the ECU illumi-
nates the engine trouble warning light and provides the engine with alternate operating instructions that
are appropriate for the type of malfunction.
When an abnormal signal is received from a sensor, the ECU processes the specified values that are
programmed for each sensor in order to provide the engine with alternate operating instructions that
enable the engine to continue to operate or stop operating, depending on the conditions.
ECU operation
Warning provided when
unable to start engine
Malfunction detected
FUEL INJECTION SYSTEM
FI 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. Engine trouble warning light on for 1.4 sec-
onds
8-45
Vehicle operation
Cannot be operated
Can or cannot be oper-
ated depending on the
fault code