Yamaha MT-09 2021 - Page 637

9-207
P0638
TIP
Disconnect the ECU related connectors before checking.
Refer to “PARTS CONNECTED TO THE ECU” on page 9-4.
Ground short circuit check “A”
Lines short circuit check “B”
5. Defective throttle bodies.
• Check the throttle bodies.
Refer to “CHECKING THE THROTTLE SERVO MOTOR” on page 8-63.
Between ECU coupler “2” and ground
yellow/red–ground
light green/red–ground
red/blue–ground
Throttle servo motor coupler “1”
yellow/red–any other coupler terminal
light green/red–any other coupler terminal
ECU coupler “2”
yellow/red–any other coupler terminal
light green/red–any other coupler terminal
red/blue–any other coupler terminal
Is resistance ∞ Ω?
YES
→ Go to step 5.
NO
a. Replace the wire harness.
b. Turn the main switch to “ON”, and then check the condition of the DTC using the malfunction
mode of the YDT.
Is it in the “Recovered” condition?
YES
→ Go to step 7, and complete the service.
NO
→ Go to step 5.
Y/R
Lg/R
O
Gy/RO/GP/BY/R
B R/BG/BL/BLg/R
B
G/YR/L
B/WB/WR/LL/WY/BY/RR/G
O
Gy/RO/GP/BY/R
B R/BG/BL/BLg/R
B
G/YR/L
B/WB/WR/LL/WY/BY/RR/G
2
2
1
A B