Yamaha XT660R Service Manual page 429

2. Speed sensor
• Connect the pocket tester (DC 20 V) to the
speed sensor coupler as shown.
Positive tester probe → pink 1
Negative tester probe → black/white 2
P O/R
• Set the main switch to "ON".
• Elevate the rear wheel and slowly rotate it.
• Measure the voltage (DC 5 V) of pink and
black/white. With each full rotation of the
rear wheel, the voltage reading should
cycle from 0.6 V to 4.8 V to 0.6 V to 4.8 V.
• Does the voltage reading cycle correctly?
YES
This circuit is OK.
L W
B/W
B/L
NO
Replace the speed
sensor.
SIGNALING SYSTEM
7. The coolant temperature warning light fails
to come on.
1. Coolant temperature warning light LED
• Check the LED of the coolant temperature
warning light.
Refer to "CHECKING THE BULBS AND
BULB SOCKETS".
• Is the coolant temperature warning light
LED OK?
2. Voltage
• Connect the pocket tester (DC 20 V) to the
meter assembly coupler (wire harness
end) as shown.
Positive tester probe → yellow/blue 1
Negative tester probe → black/white 2
• Set the main switch to "ON".
• Measure the voltage (DC 5 V) of yellow/
blue 1 on the meter assembly coupler
(wire harness end).
• Is the voltage within specification?
8 - 47
ELEC
YES
Replace the meter
assembly.
Ch R/G Y G/W Y/L
Dg G/L R/W B/W Lg
G G/L R/W B/W Lg
Ch R/G Y G/W Y/L
YES
The wiring
from the ECU to the
meter assembly cou-
pler is faulty and
must be repaired.
– +
NO
NO
circuit