Diodes; Electronic Throttle Control (Workman Hdx) - Toro Workman HD Series Service Manual

Diodes

A diode is used for starting circuit protection from voltage
spikes that occur when the starter solenoid is de−ener-
gized.
If a vehicle is equipped with the optional High Flow Hy-
draulics Kit, an additional diode is used for circuit protec-
tion from voltage spikes that occur when the Kit hydraulic
solenoid is de−energized.
If a vehicle is equipped with the optional light kit that in-
cludes flashers, two (2) additional diodes are used for
flasher circuit logic.
These diodes plug into the vehicle wiring harness at vari-
ous locations (see appropriate vehicle electrical sche-
matic and wire harness drawings in Chapter 11 −
Electrical Drawings).
Testing
The diodes can be individually tested using a digital
multimeter (diode test or ohms setting) and the table to
the right.

Electronic Throttle Control (Workman HDX)

The engine speed on the Workman HDX (Kubota EFI
gasoline engine) is controlled by an electronic throttle
system. The system includes an electronic throttle con-
trol at the accelerator pedal and a throttle control valve
at the Kubota gasoline engine. The engine ECU uses the
position of the throttle control at the accelerator pedal as
an input to determine the appropriate signal output for
the throttle control valve at the engine to set the engine
speed.
The electronic throttle control at the accelerator pedal is
a non−contact rotary hall effect sensor that varies output
voltage based on the sensor position. Use the Kubota
Gasoline Service Tool (KGST) and software, and the
Kubota Diagnostic Manual for WG972 engines to test
the electronic throttle control. Contact your Toro distrib-
utor for assistance in Kubota engine troubleshooting.
Electrical System
1
1. Diode
2. Male terminal
Multimeter
Red Lead (+)
on Terminal
Female
Male
1. Accelerator pedal
Page 8 − 20
Figure 26
3. Female terminal
Multimeter
Black Lead (−) Continuity
on Terminal
Male
Female
Figure 27
2. Rotary hall effect sensor
Workman HD Series
2
3
YES
NO
2
1