Yamaha 2003 YZ450F Owner's Service Manual page 584

TPS (THROTTLE POSITION SENSOR) SYSTEM
EC690000
TPS (THROTTLE POSITION SENSOR) SYSTEM
INSPECTION STEPS
If the TPS will not operate, use the following inspection steps.
Check entire ignition
system for connection.
Check TPS.
*Check CDI magneto.
Check CDI unit.
*marked: Refer to "IGNITION SYSTEM" section.
NOTE:
Use the following special tools in this inspection.
Pocket tester:
YU-3112-C/90890-03112
OK
OK
Source coil
OK
TPS input
No good
No good
TPS coil
No good
No good
voltage
Inductive tachometer:
Engine tachometer:
6 - 7
ELEC
Repair or replace.
Replace.
Replace.
Replace.
YU-8036-B
90890-03113
– +