Toro Groundsmaster 4500-D Service Manual page 235

Solenoid Coil Testing
1. Park machine on a level surface, lower cutting
decks, stop engine, engage parking brake and remove
key from the ignition switch.
2. Locate hydraulic solenoid valve coil to be tested (Fig.
51).
3. Disconnect wire harness connector from solenoid
valve 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 val-
ue from from the measured value of the component you
are testing.
4. Using a multimeter (ohms setting), measure resis-
tance between the two (2) connector terminals on the
solenoid valve coil.
NOTE: Solenoid coil resistance should be measured
with solenoid at approximately 68
may be slightly different than listed at different tempera-
tures. Typically, a failed solenoid coil will either be
shorted (very low or no resistance) or open (infinite re-
sistance).
A. If coil is secured to valve with a nut, identify coil by
measuring the coil diameter and coil height (Fig. 52).
The correct resistance for the solenoid coil is identi-
fied in the table below.
COIL COIL
DIAMETER HEIGHT
1.84 in 1.96 in
(46.7 mm) (49.9 mm)
1.41 in 1.43 in
(35.8 mm) (36.3 mm)
B. The resistance of the solenoid valve coil in the HI/
LOW range control manifold (item 4 in Figure 51) is
7.1 ohms.
5. If solenoid coil resistance is incorrect, replace coil
(see appropriate control manifold information in the Ser-
vice and Repairs section of Chapter 4 -- Hydraulic Sys-
tem).
6. After testing is completed, connect wire harness
connector to the solenoid valve coil.
Groundsmaster 4500--D/4700--D
o o
F (20 C). Resistance
COIL
RESISTANCE
7.1 ohms
8.8 ohms
Page 5 - - 43
COIL
DIAMETER
COIL
HEIGHT
Figure 52
Electrical System