Toro Groundsmaster 5900 Series Service Manual page 387

Solenoid Coil Testing
Groundsmaster ® 5900 & 5910
16227SL Rev B
1. Park machine on a level surface, lower cutting decks, stop engine and
remove key from the key switch.
2. Turn battery−disconnect switch to the OFF position.
3. Locate piston pump solenoid coil to be tested and disconnect wire harness
connector from solenoid coil
Note: Prior to taking small resistance readings with a digital multimeter, short
the meter test leads together. The meter will display a small resistance value
(usually 0.5 ohms or less). This resistance is due to the internal resistance
of the meter and test leads. Subtract this value from the measured value
of the component you are testing.
4. Using a multimeter (ohms setting), measure resistance between the two (2)
connector terminals on the solenoid coil. Solenoid coil resistance should be
3.66 ohms.
Note: Solenoid coil resistance should be measured with solenoid at
approximately 20 ºC (68 ºF). Resistance may be slightly different than listed
at different temperatures. Typically, a failed solenoid coil will either be shorted
(very low or no resistance) or open (infinite resistance).
5. If solenoid coil resistance is incorrect, replace coil as follows:
A. Use a 12 point, 26 mm socket to loosen and remove the coil nut that
secures solenoid coil.
B. Slide solenoid coil and O−rings from valve stem. Discard the O−rings and
clean all corrosion or dirt from the valve.
C. Lubricate new O−rings with petroleum jelly and slide new coil with
O−rings onto the solenoid stem.
D. Use a 12 point, 26 mm socket to install and tighten coil nut from 5 N·m
(44 in−lb). Do not over−tighten coil nut.
6. If solenoid coil resistance is correct and a circuit problem still exists, check
the wire harness (see
7. After testing is completed, connect wire harness connector to the solenoid
coil.
8. Turn the battery−disconnect switch to the ON position before returning the
machine to service.
(Figure 268).
Appendix A (page A–1)).
Page 6–125 Electrical System: Component Testing