Toro 41188, Service Manual

Page: 141 / 353

Multi Pro 1750
Page 5 − 39
Electrical System
Traction Speed Sensor
The traction speed sensor is attached to the upper
transaxle cover (Fig. 39). It uses a magnetically based,
Hall Effect integrated circuit. As the differential ring gear
in the transaxle turns, the sensor accurately senses the
movement of the gear teeth passing by the sensor.
The Toro Electronic Controller (TEC) monitors the op-
eration of the speed sensor (input). Information from the
speed sensor is used by the speed lock system and for
product application calculations. The speed sensor
must be calibrated for accurate speed calculations (see
Machine Operator’s Manual).
Testing
1. Park machine on a level surface, stop spray pump,
stop engine and engage parking brake. Remove key
from ignition switch.
2. Locate traction speed sensor on the transaxle as-
sembly. Disconnect the wire harness connector from the
traction speed sensor.
3. Remove cap screw and lock washer securing sensor
to transaxle. Remove speed sensor from transaxle.
4. Connect positive multimeter test lead to the sensor
connector gray striped wire terminal and the negative
multimeter lead to the connector black wire terminal
(Fig. 40). Set multimeter to ohms setting.
IMPORTANT: Incorrect jumper wire connections
during testing can damage the sensor.
5. Using a +12 VDC battery, a multimeter, a 1K ohm re-
sistor and appropriate jumper wires, connect the battery
and multimeter to the speed sensor (Fig. 40).
6. Set multimeter to DC volts setting. The multimeter
should display very low voltage when a metal object is
held near the sensor tip. The multimeter should display
battery voltage when the metal object is moved away
from the sensor tip. Replace speed sensor if necessary.
7. After testing is complete, install speed sensor into
transaxle and secure with cap screw and lock washer.
Connect speed sensor to wire harness.
8. If the speed sensor tests correctly and a circuit prob-
lem still exists, check wire harness (see Electrical Sche-
matic and Wire Harness Drawings in Chapter 10 −
Electrical Drawings in this manual).
1. Speed sensor
2. Flange head screw
3. Seal
Figure 39
1
2
3
1. Speed sensor
2. Sensor tip
3. Sensor connector
4. Red striped wire (+)
5. Gray striped wire (signal)
6. Black wire (−)
Figure 40
B A C
−
+
12 VDC
6
4
3
1
5
1K ohm
resistor
2
Electrical
System