Yamaha MTN850-A 2017 Service Manual page 384

The speedometer fails to operate.
1. Check the rear wheel sensor.
Refer to "MAINTENANCE OF THE
REAR WHEEL SENSOR AND
SENSOR ROTOR" on page 4-22.
OK
2. Check the entire wheel sensor wir-
ing.
Refer to TIP.
OK
Replace the hydraulic unit assembly,
ECU, meter assembly.
Refer to "REPLACING THE ECU
(Engine Control Unit)" on page 8-157.
TIP
Repair or replace if there is an open or short circuit.
• Between rear wheel sensor coupler and ABS ECU coupler.
(white–white)
(black–black)
• Between ABS ECU coupler and ECU coupler.
(white/green–white/green)
(white/yellow–white/yellow)
• Between ECU coupler and meter assembly.
(light green/blue–light green/blue)
(light green/white–light green/white)
The coolant temperature warning light fails to come on.
1. Check the coolant temperature sen-
sor.
Refer to "CHECKING THE COOL-
ANT TEMPERATURE SENSOR"
on page 8-169.
OK
2. Check the entire signaling system's
wiring.
Refer to "CIRCUIT DIAGRAM" on
page 8-21.
OK
Replace the ECU or meter assembly.
Refer to "REPLACING THE ECU
(Engine Control Unit)" on page 8-157.
Replace the rear wheel sensor.
NG
Properly connect or repair the wheel sen-
sor wiring.
NG
Replace the coolant temperature sensor.
NG
Properly connect or repair the signaling
system's wiring.
NG
8-27
SIGNALING SYSTEM