Yamaha MTN850-A 2017 Service Manual page 471

Standard key code voiding method
a. Main switch "ON"
b. Main switch "OFF"
c. LED on
d. LED off
e. Less than 5.0 s
f. Code re-registering key
g. Remaining standard key
h. Registration mode
A. If the immobilizer system indicator light stops
flashing 5 seconds after the first standard key
is registered, the second standard key cannot
be registered.
IMMOBILIZER SYSTEM
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