Daewoo Korando. Manual - part 246

AUTOMATIC TRANSMISSION  5A-27

Shift Lever Position

Manual 1

Manual 2

Manual 3

Drive

Netural

Reverse

Park

Resistance (OHMS)

1k - 1.4k

1.8k - 2.2k

3k - 3.4k

4.5k - 4.9k

6.8k - 7.2k

10.8k - 11.2k

18.6k - 19k

Table 3.3 - Readings for Resistance/Shift Lever Positions

Diagnostics Inputs

The diagnostics control input or K-line is used to initiate the outputting of diagnostics data from the TCU to a diagnostic
test instrument. This input may also be used to clear the stored fault history data from the TCU’s

retentive memory. Connection to the diagnostics input of the TCU is via a connector included in the vehicle’s wiring

harness or computer interface. Refer to the vehicle manufacturer’s manual for the location of the self test

connectors.

Battery Voltage Monitoring Input

The battery voltage monitoring input connects to the positive side of the battery. The signal is taken from the

main supply to the TCU.

If operating conditions are such that the battery voltage at the TCU falls below 11.3V the transmission will adopt a ‘low
voltage’ mode of operating in which shifts into first gear are inhibited. All other shifts are allowed but may not occur
because of the reduced voltage. This condition normally occurs only when the battery is in poor condition.

When system voltage recovers, the TCU will resume normal operation after a 3 second delay period.

TCU Outputs

The outputs from the TCU are supplied to the components described below:

Solenoids

The TCU controls seven solenoids. Solenoids 1 to 6 (S1 to S6) are mounted in the valve body, while Solenoid 7 (S7)
is mounted in the pump cover. The normal state (OPEN/CLOSED) and the functions associated with the solenoids
are detailed in table 3.4. Table 3.5 details the S1 and S2 logic for static gear states. The logic during gear changes for
S1 to S4 and S7 is detailed in table 3.6.

5A-28  AUTOMATIC TRANSMISSION

Table 3.4 - Solenoid States and Functions

Table 3.5 - Solenoid Logic for Static Gear States

Solenoids 1 and 2

Solenoids 3 and 4

Solenoid 5

Solenoid 6

Solenoid 7

S1 and S2 are normally open On/off solenoids that set the selected gear.

These solenoids determine static gear position by operating the shift valves.

Refer to table 3.5. Note that S1 and S2 solenoids also send signal pres-

sure to allow or prohibit rear band engagement.

S3 and S4 are normally open On/off solenoids that combine to control

shift quality and sequencing. S3 switches the clutch regulator valve off or

on. S4 switches the front band regulator valve off or on.

S5 is a variable force solenoid that ramps the pressure during gear

changes. This solenoid provides the signal pressure to the clutch and

band regulator, thereby controlling the shift pressures.

S6 is a normally open On/off solenoid that sets the high/low level of line

pressure, Solenoid off gives high pressure.

S7 is a normally open On/off solenoid that controls the application of the

converter clutch. Solenoid on activates the clutch.

S2

ON

ON

OFF

OFF

OFF

OFF

OFF

S1

ON

OFF

OFF

ON

OFF

OFF

OFF

Gear

1st

2nd

3rd

4th

Reverse

Neutral

Park

AUTOMATIC TRANSMISSION  5A-29

Table 3.6- Solenoid Operation During Gearshifts

To Initiate Shift

S1 OFF

S4 ON

S1 OFF

S2 OFF

S3 ON

S4 ON

S2 OFF

S3 ON

S4 ON

S2 OFF

S3 ON

S4 ON

S1 ON

S4 ON

S4 ON

S3 ON

S3 ON

S4 ON

S2 ON

S4 ON

S3 ON

S4 ON

S4 ON

S7 ON

To Complete Shift

S4 OFF

S3 OFF

S4 OFF

S3 OFF

S4 OFF

S3 OFF

S4 OFF

S4 OFF

S1 OFF

S4 OFF

S1 OFF

S2 ON

S3 OFF

S2 ON

S3 OFF

S4 OFF

S4 OFF

S1 ON

S2 ON

S3 OFF

S4 OFF

S1 ON

S4 OFF

S7 OFF

Typical S5 Current Ramp

750mA to 600mA

850mA to 750mA

850mA to 750mA

700mA to 500mA

750mA to 600mA

750mA to 900mA

750mA to 950mA

600mA to 1000mA

600mA to 450mA @ 20 kph.

550mA to 400mA @ 60 kph.

800mA to 650mA @ 100 kph.

700mA to 950mA

800mA to 950mA

700mA to 400mA

600mA to 100mA

Shift

1-2

1-3

1-4

2-3

3-4

4-3

4-2

4-1

3-2

3-1

2-1

Conv. Clutch

ON

OFF

5A-30  AUTOMATIC TRANSMISSION

Solenoid Valve Symbols (On/off Solenoids)

The solenoid symbol shown adjacent to each solenoid on the
hydraulic system schematics indicates the state of the oil flow
through the solenoid valve with the power On or 0ff. Refer to
figure 3.6 for the On/off operational details of NO solenoid
valves.

Normally Open (NO) Solenoid

POWER ON

Line 500 port is closed. The output port is open to exhaust at
the solenoid valve.

POWER OFF

The exhaust port is closed. The output port is open to line 500,

Figure 3.6- Normally Open (NO) Symbols

Variable Pressure Solenoid Multiplexing System

Friction element shifting pressures are controlled by the variable pressure solenoid (VPS).
Line pressure is completely independent of shift pressure and is a function of throttle position, gear state and engine
speed.
S5 is a proportional or variable pressure solenoid that provides the signal pressure to the clutch and band regulator
valves thereby controlling shift pressures.
VPS pressure is multiplexed to the clutch regulator valve, the band regulator valve and the converter clutch regulator
valve during automatic gearshifts.
A variable pressure solenoid produces a hydraulic pressure inversely proportional to the current applied. During a
gearshift the TCU applies a progressively increasing or decreasing (ramped) current to the solenoid. Current applied
will vary between a minimum of 200 mA and a maximum of 1000 mA, Increasing current decreases output (55)
pressure. Decreasing current increases output (55) pressure.
Line 500 pressure, (approximately 440 to 560 kPa), is the reference pressure for the VPS, and the VPS output
pressure is always below line 500 pressure.
When the VPS is at standby, that is no gearshift is taking place, the VPS current is set to 200 mA giving maximum
output pressure.
Under steady state conditions the band and clutch regulator valve solenoids are switched off. This applies full Line
500 pressure to the plunger and because Line 500 pressure is always greater than S5 pressure it squeezes the S5
oil out between the regulator valve and the plunger. The friction elements are then fed oil pressure equal to Line 500
multiplied by the amplification ratio.
When a shift is initiated the required On/off solenoid is switched on cutting the supply of Line 500 to the plunger.
At the same time the VPS pressure is reduced to the ramp start value and assumes control of the regulator valve by
pushing the plunger away from the valve. The VPS then carries out the required pressure ramp and the timed shift is
completed by switching Off the On/off solenoid and returning the VPS to the standby pressure.
This system enables either the band or clutch or both to be electrically controlled for each gearshift.

Mode Indicator Light

Depending on the application, the mode indicator light may be used to indicate the mode that has been selected or
if an overheat condition exists. The mode indicator light is usually located on the instrument cluster.

Communication Systems

CAN

The controller area network (CAN) connects various control modules by using a twisted pair of wires, to share
common information. This results in a reduction of sensors and wiring. Typical applications include using the engine
controller to obtain the actual engine speed and throttle position, and adding these to the network. The ABS controller
(if fitted) can be used to obtain the road speed signal. This information is then available to the TCU without any
additional sensors.