Troubleshooting - Yamaha MTN850-A 2017 Service Manual

EAS30492

TROUBLESHOOTING

The ignition system fails to operate (no spark or intermittent spark).
TIP
• Before troubleshooting, remove the following part(s):
1. Rider seat
2. Air scoop
3. Front side panel
4. Fuel tank cover
5. Fuel tank
6. Air filter case
1. Check the fuses.
(Main, ignition and fuel injection
system)
Refer to "CHECKING THE FUSES"
on page 8-156.
OK
2. Check the battery.
Refer to "CHECKING AND
CHARGING THE BATTERY" on
page 8-158.
OK
3. Check the spark plugs.
Refer to "CHECKING THE SPARK
PLUGS" on page 3-5.
OK
4. Check the ignition spark gap.
Refer to "CHECKING THE IGNI-
TION SPARK GAP" on page 8-164.
NG
5. Check the ignition coils.
Refer to "CHECKING THE IGNI-
TION COILS" on page 8-163.
OK
6. Check the crankshaft position sen-
sor.
Refer to "CHECKING THE CRANK-
SHAFT POSITION SENSOR" on
page 8-164.
OK
7. Check the main switch.
Refer to "CHECKING THE
SWITCHES" on page 8-153.
OK
8. Check the start/engine stop switch.
Refer to "CHECKING THE
SWITCHES" on page 8-153.
OK
Replace the fuse(s).
NG
• Clean the battery terminals.
• Recharge or replace the battery.
NG
Re-gap or replace the spark plugs.
NG
Ignition system is OK.
OK
Replace the ignition coils.
NG
Replace the crankshaft position sensor.
NG
Replace the main switch/immobilizer unit.
NG
Replace the handlebar switch (right).
NG
8-5
IGNITION SYSTEM