Yamaha MT-09 2021 - P056 C; Troubleshooting

9-194
P056C
EAS20595
P056C
EAS33075
TROUBLESHOOTING
Item
• Front brake light switch: open or short circuit is detected.
• Rear brake light switch: open or short circuit is detected.
Fail-safe system
• Able to start engine
• Able to drive vehicle
Procedure
1. Locate the malfunction.
a. Execute the diagnostic mode. (Code 82, 83)
TIP
Perform the procedure from step 2 to step 5, and from step 10 to step 11.
b. Execute the diagnostic mode. (Code 82, 83)
c. Confirm that it is defective.
d. Go to step 6.
TIP
Perform the procedure from step 6 to step 11.
2. Connection of ECU coupler, front brake light switch coupler, brake light relay coupler and main
switch coupler.
• Check the locking condition of the coupler.
• Disconnect the coupler and check the pins (bent or broken terminals and locking condition of the
pins).
When the front brake is applied ON
When the front brake is not applied OFF
Is check result OK?
YES
→Go to step b.
NO
→Go to step 2.
When the rear brake is applied ON
When the rear brake is not applied OFF
Is the coupler condition normal?
YES
→Go to step 3.
NO
a. Connect the coupler securely or replace the wire harness.
b. Turn the main switch to “ON”.
c. Operate the front brake lever, and then check the condition of the DTC using the malfunction
mode of the YDT.