Yamaha UMAX Service Manual page 302

Fault code No.
Display name
Symptom
Step Inspection items
4 Wire harness continuity
5 Malfunction in MCU
6 Operation check
Fault code No. 37
Fault code No.
Display name
Symptom
Step Inspection items
1 Resetting the MCU
2 Shift switch
3 Wire harness continuity
4 Malfunction in MCU
PC GENIUS DIAGNOSTIC SYSTEM (YUM2E)
36
Invalid logic for TPS and switch
Mismatch between the accelerator switch and throttle position sensor
Vehicle stopped
Diagnostic procedure
Open or short circuit → Properly
connect or replace the wire
harness.
Between the accelerator switch
coupler and MCU coupler.
Red/white–Red/white
Brown–Brown
Between the throttle position
sensor coupler and MCU
coupler.
Orange–Orange
Blue–Blue
Black–Black
Replace the MCU.
Set the TOW switch to RUN, the
main switch to ON, depress the
accelerator pedal, and check if
the vehicle runs.
37
Invalid logic for shift switch
Shift switch mismatch
Vehicle stopped
Diagnostic procedure
Cycle the TOW switch off and
on (RUN → TOW → RUN).
Checking the shift switch.
Refer to "CHECKING THE
SWITCHES" on page 8-61.
Replace if defective.
Open or short circuit → Properly
connect or replace the wire
harness.
Between the shift switch coupler
and MCU coupler.
Yellow–Yellow
White–White
Black–Black
Replace the MCU.
9-17
Confirmation steps after
diagnostic procedure
Connect the PC Genius
diagnostic tool, and check if any
errors are continuously
occurring.
OK → Go to step 6.
NG → Go to step 5.
Go to step 6.
OK → Maintenance job
completion.
NG → Refer to "Vehicle
stopped" on page 9-23.
Confirmation steps after
diagnostic procedure
Connect the PC Genius
diagnostic tool, and check if any
errors are continuously
occurring.
OK → Go to step 5.
NG → Go to step 2.
Connect the PC Genius
diagnostic tool, and check if any
errors are continuously
occurring.
OK → Go to step 5.
NG → Go to step 3.
Connect the PC Genius
diagnostic tool, and check if any
errors are continuously
occurring.
OK → Go to step 5.
NG → Go to step 4.
Go to step 5.