Ecu's Self-Diagnostic Function - Yamaha YBR250 2007 Service Manual

ECU'S SELF-DIAGNOSTIC FUNCTION

The ECU is equipped with a self-diagnostic function in order to ensure that the engine control 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, it becomes
stored in the ECU memory in the form of a fault code.
• To inform the rider that the fuel injection stop function is active, the engine trouble warning light
blinks while the start switch is being pressed to start the engine.
• If a malfunction in the system is detected by the self-diagnostic function, this mode provides an
appropriate substitute characteristic operation, and alerts the rider of the detected malfunction by
illuminating a engine trouble warning light.
• After the engine has been stopped, the lower fault code will be displayed at the failure warning
light (or at the F.I. diagnostic tool display). Once a self-diagnostic fault code has been displayed,
it remains stored in the ECU memory until a deletion operation is performed.
Engine trouble warning light fault code indication
Ten digit: Cycles of 1 sec ON and 1.5 sec OFF.
Unity digit: Cycles of 0.5 sec ON and 0.5 sec OFF.
<Example>: Fault code number 42.
Light ON
Light OFF
FUEL INJECTION SYSTEM
6-3
FI