Key Start Latch And Magneto/Ecu Relays - Toro Workman GTX Service Manual

Key Start Latch and Magneto/ECU Relays

A Workman GTX vehicle uses up to three (3) identical
relays that have five (5) terminals. The relays are at-
tached to the dash bracket near the brake master cylin-
der (Fig. 18).
Two relays work together to operate the start latch cir-
cuits so that the engine can be started when the key
switch is rotated to the START position. If the engine is
started with the key switch, the engine will continue to
run due to the latch relays until the key switch is moved
to the OFF position.
A third relay is used to manage the magneto on ma-
chines with a carbureted engine (machine serial number
before 401400000), or the ECU on machines with elec-
tronic fuel injection (EFI).
Machines with a carbureted engine (machine serial
number before 401400000): when the key switch is
in the OFF position, the magneto relay is not ener-
gized and the engine magneto is grounded to pre-
vent engine operation. When the key switch is in the
RUN or START position, the magneto relay is ener-
gized which allows the engine to operate.
Machines with a fuel injected engine: when the key
switch is in the OFF position, the ECU relay is not be
energized and the engine ECU is switched OFF.
When the key switch is in the RUN or START posi-
tion, the ECU relay is energized and the ECU is
switched ON. To prevent the engine ECU from
switching ON/OFF rapidly when using the accelera-
tor pedal start feature, a delay timer works with the
ECU relay to keep the ECU energized for 30 seconds
after the engine stops (magneto grounded).
Testing
1. Park vehicle on a level surface, stop engine, engage
parking brake and remove key from the key switch.
Place vehicle shift lever in the NEUTRAL position.
2. Raise hood to gain access to relays.
3. Locate relay that is to be tested and disconnect the
wire harness connector from the relay. Remove relay
from vehicle for easier testing.
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.
Electrical System
1. Magneto/ECU relay
2. Key start latch relays
4. Using a multimeter (ohms setting), measure coil re-
sistance between terminals 85 and 86 (Fig. 19). Resist-
ance should be between 70 and 90 ohms.
5. Connect multimeter (ohms setting) leads to relay ter-
minals 30 and 87 (Fig. 19). Ground terminal 86 and ap-
ply +12 VDC to terminal 85. The relay should make and
break continuity between terminals 30 and 87 as +12
VDC is applied and removed from terminal 85.
6. Disconnect voltage from terminal 85 and multimeter
lead from terminal 87.
7. Connect multimeter (ohms setting) leads to relay ter-
minals 30 and 87A. Apply +12 VDC to terminal 85. The
relay should make and break continuity between termi-
nals 30 and 87A as +12 VDC is applied and removed
from terminal 85.
8. Disconnect the voltage and multimeter leads.
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Figure 18
3. Brake master cylinder
86 87A 87
85 30
Figure 19
Workman GTX Gasoline