450
Model Code Page
31. CareTel
1. 4. 1997
6000--8750 361 2
2. Sensors
a) Engine oil pressure sensor S13
Transmission oil pressure sensor S17
When the lubricating oil pressures drop under a certain
level, the sensors ground the electric circuit and a warning
light in question comes on in the dashboard (LOW). When
the pressure rises up to a certain level, the sensor cuts off
the circuit and the warning light goes out (OK).
Start the engine and ensure that the warning lights do not
light. Disconnect the sensor wire and connect it to tractor
frame at which time the warning light in question comes on.
Connect the wire to the sensor pin and the warning light
should go out.
Stop the engine, at which time the warning lights come on
and light if the current is switched on. If the warning lights
function as shown above, the sensors and wires are prob-
ably in order.
b) Engine temperature sensor B9C
Resistance values of the sensor:
--- 120---148 Ω (+60˚C)
--- 4 7 --- 5 6 Ω (+90˚C)
--- 3 5 --- 4 2 Ω (+100˚C)
(the resistance increases when temperature lowers).
CareTel temperature value can be compared with the read-
ing of the dashboard temperature gauge at which time can
be estimated the size class of the value. The working tem-
perature of the engine varies between +75...+95˚C
according to loading. Engine coolant temperature can be
measured with an auxiliary thermometer, at which time is
obtained a more accurate value of comparison.
c) Transmission oil temperature sensor B3
Resistance values of the sensor:
--- 200---250 Ω (+60˚ C)
--- 7 5 --- 9 0 Ω (+90˚ C)
(the resistance increases when temperature lowers).
If the tractor is equipped with Agrodata---instrument, the
function of this sensor can be checked by ensuring that the
AD---instrument shows a correct temperature value, see
code 331.
In the dashboard there is a warning light for too high tem-
perature in the transmission. Transmission oil working tem-
perature varies between +60...+85 ˚C according to the
loading.
d) PTO shaft rotation speed sensor B7
Resistance of the sensor should be 1,0---1,10 kΩ.
If the tractor has AD---instrument, check whether it shows
the PTO revs. If it shows the revs and the reading reacts to
the alterations of the revs, the sensor is in order.
e) Pressure sensor B1L for low pressure circuit
The basic pressure of this circuit is 18 ---19 bar. The circuit
maintains clutch pressures in various transmission multi---
disc clutches, such as DPS, lock, 4WD, PTO, see pages
911/1---2. Sensor output voltage (DC) depends on the pres-
sure linearly, see diagram below. The connector must be
connected to the sensor when measuring output voltages.
Allowable
deviation
Output
Others
Engine revs and running hours
CareTel takes engine revs and running hours from the alter-
nator. In the dashboard there is a rev counter. If it seems to
function and reacts to the revs alterations, the measuring
circuit is in order.
CareTel running hour reading can be checked by compar-
ing it with the reading in the dashboard.
CareTel takes the engine running mode (*) from the igni-
tion switch position and engine revs (charging light), so that
when the engine revs are over 400 r/min, CareTel assumes
that the engine is running, if the ignition switch is in the run-
ning position.
Engine moment and Σ-- power
These functions only on 8750 tractor, which has Σ--- pow er,
see under code 313.
In point SP there is ON, when the engine is working in the
higher output range, at which time also the dashboard
ETB---light lights, otherwise OFF.
CareTel shows the engine torque as percents of the total
torque.
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