Toro Groundsmaster 4500-D Service Manual page 79

Mow Circuit Problems
Problem
None of the cutting decks will oper-
ate.
NOTE: To engage the mow circuit,
the seat must be occupied, the cut-
ting deck(s) must be fully lowered,
the traction speed must be in the
LOW (mow) position and the PTO
switch must be ON.
One cutting deck will not operate.
Several cutting decks will not oper-
ate.
Groundsmaster 4500--D/4700--D
Possible Cause
Cutting decks are not fully lowered to ground.
PTO switch is not in engaged position.
Operator seat is unoccupied.
Traction system is in HI speed (transport).
Engine temperature is excessive causing cutting decks to be disen-
gaged (Fault should be displayed on InfoCenter).
Electrical problem exists that prevents deck control manifold sole-
noid valve operation (see Chapter 5 -- Electrical System).
Gear pump sections that supply mow circuits are damaged.
Circuit pressure to the affected deck motor is low.
Cutting deck problem exists (see Chapter 8 -- Cutting Decks).
Spline on affected deck motor (or spindle) is damaged.
Deck motor relief valve is stuck or damaged.
Deck motor is damaged. NOTE: If appropriate, transfer a suspected
damaged motor to another cutting deck. If problem follows the motor,
motor needs repair or replacement.
On Groundsmaster 4700--D, deck is not fully lowered to ground
(decks #6 and #7).
On Groundsmaster 4700--D, cartridge valve SV1 or SV2 in deck con-
trol manifold is damaged or sticking (decks #6 and #7).
Electrical problem exists that prevents deck control manifold sole-
noid valve operation (see Chapter 5 -- Electrical System).
Decks are not fully lowered to ground.
Deck control manifold solenoid cartridge valve (PRV1 or PRV2) for
affected decks is faulty.
Logic cartridge valve (LC1 or LC2) in deck control manifold is stuck
or damaged.
Gear pump section (first or second section) is worn or damaged.
Page 4 - - 39 Hydraulic System