Yamaha YBR250 2007 Service Manual page 349

6. The speedometer fails to operate.
1. Voltage
• Connect the pocket tester (DC 20 V) to the
panel coupler (wire harness), as shown.
Positive tester probe --> blue/yellow 1
Negative tester probe --> blue/black 2
2
1
• Set the main switch to "ON".
• Lift the rear wheel and spin it slowly.
• Measure the voltage (DC 5 V) of blue/
yellow 1 on the panel coupler (wire
harness).
• Is the voltage within the specified?
YES
SIGNALING SYSTEM
NO
Replace the panel.
7-39
2. Speed sensor
• Connect the pocket tester (DC 20 V) to
the speed sensor, as shown.
Positive tester probe --> blue/yellow 1
Negative tester probe --> blue/black 2
1
LYLB
2
• Set the main switch to "ON".
• Lift the rear wheel and spin it slowly.
• Measure the voltage (DC 5 V) at each full
turn of the rear wheel, the voltage reading
should oscillate around the levels 0.6 V to
4.8 V to 0.6 V to 4.8 V.
• Is the voltage reading routes correctly
through the cycles?
YES
The circuit is OK.
ELEC
LB
LY
NO
Replace the speed
sensor.