DRESSTA TD-25M EXTRA, Service Manual

Page: 293 / 595

ELECTRICAL
SECTION 8
Page 17
DRESSTA TD-25M EXTRA
WIRING DIAGRAM
The same will be true if the presetting mode switch is set in its “1/2” position (yellow diode
L29
ON). The same status will be if one of the range switches of the control lever is in the LO
range and the other in HI. If two switches are set to HI range then “L” displayed will change to “H”
after a second elapsed. Have in mind that the display will dim at a startup only.
After power up when the presetting mode switch is in “2/2” position (a yellow diode
L28
will come
on) “2” gear will display and the solenoid valve
EZ2
will get activated. Then diode
L18
will blink (for
a fraction of a second), then it will come off and a green diode
L17
will come on.
After power up with the drive train neutral lock lever in the locked position and the locked position
switch is operative and adjusted correctly, the yellow diode
L3
will come on. After power up,
depending on a machine type, the yellow diodes
L19
,
L20
,
L21
will come on brightly, (refer to
Table 8.1), what witnesses to machine type correct code.
A yellow diode
L25
may come on too what will signal that the auto downshift mode is operative.
c. Controller operation after engine startup
After engine startup the red diodes
L22
and
L23
have to be ON what will signal that the controller
has been fed with a pulse train from the magnetic sensors.
d. Power up with the control system inoperative
NOTE: Bear in mind that if magnetic sensors for torque converter output RPM (CIW) or engine
RPM (CS) are replaced then the drive control system may malfunction in case the sensors relative
position has been disturbed.
1. If at power up only “L” displays, check J, P pins of the Deutsch connector providing power to the
controller for voltage presence.
a) If U < 18 [V], the controller processor operation has been held up by power supply watchdog.
Turn the control system off, check the cause for voltage down, clear the fault and restart the
power supply.
b) If the voltage is OK, and the green diode
L18
will not come on, then EPD has tripped as
a result of system over voltage, short circuit or overloading condition. EPD will cut power to
the controller. When this happens only machine “limp home” mode is possible. (1
st
gear and
low range).
For EPD to restore the controller power, cut the power to the drive control system, clear the
short (overloading) cause or source of disturbance and then restore power to the drive
control system; if with the power restored after a 7 second power down the “L” would display
only that means the cause for EPD tripping has not been cleared.
2. If at power up and gear up shift with high range the controller will downshift automatically with
subsequent range reduction to “1L”, and symbols for gear and range will display, then voltage
calls for recheck.
a) At momentary power down to below 18 [V], the controller processor will reset and then
restart. A 10 [A] automatic circuit breaker - and/or its wiring - which protects the entire drive
control system, solenoid valves included, can be at fault.
b) With the over voltage U > 36 [V], the alternator (alternator voltage regulator) which sets the
outputted voltage level can be at fault.
3. If at power up all or a single yellow diode
L19
,
L20
,
L21
fails to come on at full brightness and
the red diode
L24
will come on, this means that the machine type coding is at fault - at least one
of the pins A, H, V (refer to Table 8.1) got corrupted.
4. If a single solenoid valve is at fault, take a voltage check at the solenoid valve coil’s terminals.
DO NOT take a voltage to the machine ground.