SsangYong Rexton. Service manual - part 593

SSANGYONG  Y200

5D2-20  TRANSFER CASE - TOD

SYSTEM OPERATION

Initial Operation of TOD Control Unit

When ignition “ON”, “4L” and “4WD check” lamps
illuminates for 0.6 second to check bulb in instrument
panel, then perform diagnosis of system (See 3F-19
Self-Diagnosis Condition).

Position Encoder

The Position Encoder is used by the TOD to determine
the position of the Shift Motor. Each motor position is
identified by a position code below.

Notice:

•

All other position codes are invalid

•

Position

Input Open Circuit (> 4.5V) = 1

•

Position Input shorted to Speed/Position Return
(< 0.5V) = 0

Position Code 1/2/3/4

1110

1010

0010

0000

1110

Motor Position

Left Stop

Left of High

High

Right of High

Zone 1

Position Code 1/2/3/4

1001

0001

0101

0100

-

Motor Position

Neutral

Zone 2

Low

Right Stop

-

TRANSFER CASE - TOD  5D2-21

SSANGYONG  Y200

System Response (Action)

No action required. 4L bulb off.

No action required. 4L bulb off.

No action required. 4L bulb off.

Blink 4L bulb. After the shift conditions are met,

attempt a shift to 4H under conditions of below 87 rpm

in front and rear propeller shaft and “Neutral” position.

After successfully shifting into 4H, stop blinking 4L

bulb.

Same as above

Same as above

Same as above

Blink 4L bulb. After the shift conditions are met,

attempt a shift to 4L. After successfully shifting into

4L, stop blinking 4L bulb.

Same as above

Blink 4L bulb. After the shift conditions are met,

attempt a shift to 4L. After successfully shifting into

4L, stop blinking 4L bulb.

Same as above

Same as above

Same as above

Same as above

Same as above

Same as above

No action required. 4L bulb on.

No action required. 4L bulb on.

Motor Position

Left Stop

Left of High

High

Right of High

Zone 1

Neutral

Zone 2

Low

Right Stop

Left Stop

Left of High

High

Right of High

Zone 1

Neutral

Zone 2

Low

Right Stop

Position Sensor Interpretation

When the module powers up, it will read the position
sensor and the 4H/4L switch input and respond to the
possible codes as follows.

4H/4L Switch Input

4H

4H

4H

4H

4H

4H

4H

4H

4H

4L

4L

4L

4L

4L

4L

4L

4L

4L

SSANGYONG  Y200

5D2-22  TRANSFER CASE - TOD

A command to shift will only be acted upon if the TOD
is reading a valid code at the time the command to
shift is made.

After a shift has started, the TOD will power the shift
motor until the code for the requested position is read.
If an invalid code is read, the TOD will go into a default
mode.

During a shift attempt, the shift motor will be energized
for a maximum of 5 seconds.

Electric Shift System Operation

The Electric Shift System is responsible for changing
the Transfer Case gear ratio by controlling the electric
shift motor. The TOD monitors the 4H/4L switch, neutral
switch, speed sensors, position encoder, and ignition
switch.

A range change is initiated when ;

1. The 4H/4L Switch is changed from 4H to 4L or

from 4L to 4H.

2. The motor position (as indicated by the position

encoder) does not match the 4H/4L Switch
immediately after the ignition is turned on.

Shift criteria

When a range change is initiated a Diagnostic Test
will be completed on the motor, speed sensors, and
position encoder. If the Diagnostic Test fails, the shift
will not be attempted. If all components are operating
properly, the TOD will attempt a range change after
the following shift criteria are met:

1. The transmission is in neutral for 2 seconds after

the shift is requested.

2. Both propeller shaft speeds are below 87 rpm

(2580 pulses/minute).

If the transmission is taken out of neutral before 2
seconds has elapsed, or either propeller shaft speed
increases above the limit, the shift will be suspended
and the 4L Indicator will continue to blink until the
criteria are met again or the 4H/4L Switch is returned
to the original position.

Range change

When the shift criteria are met, the motor is rotated in
the appropriate direction (as determined by the selector
switch) until one of the following occurs:

1. The motor reaches its destination.

2. The motor is on for 5 seconds without reaching its

destination. The shift has failed and the TOD will
respond as default mode.

3. A fault occurs with either the motor or position

encoder. Refer to the diagnosis requirement.

When the motor is energized, the Ignition, 4H/4L
Switch, propeller shaft speeds, and transmission
neutral inputs are ignored.

Indicator function on shifting

Once a range change has been initiated the 4L Indicator
will begin to blink at a rate of 0.3 seconds on, 0.3
seconds off until the shift is completed or canceled.

If a successful shift has been completed, the 4L
Indicator will be illuminated if the motor is in Low and
it will be turned off if the motor is in High.

4L Indicator illuminates as below figure.

Electric shift default mode

If the motor fails to reach its destination, the TOD will
attempt the following (in order):

1. The TOD will wait 3 seconds then attempt the shift

again.

2. If the second attempt to reach the destination fails

the TOD will wait 3 seconds then attempt to rotate
the motor back to the original position. If
successful, all future shifts will be inhibited until
the Ignition is cycled.

3. If the attempt to return to the original position fails,

the TOD will wait 3 seconds then attempt to rotate
the motor to the original position again. If the
second attempt to return to the original position is
successful, the 4WD CHECK lamp will be
illuminated, and all future shifts will be inhibited
until the Ignition is cycled.

YAD5D140

TRANSFER CASE - TOD  5D2-23

SSANGYONG  Y200

4. If the second attempt to return to the original

position fails the motor will be turned off, the “4WD
CHECK” lamp will be illuminated, and all future
shifts will be inhibited until the Ignition is cycled.

TOD TM System operation

The TODTM  System is responsible for distributing
torque between the front and rear axles. The TOD
monitors the propeller shaft speeds, operating range
(High/Low), and ABS activity and then applies a
calculated amount of torque to the front axle by Pulse
Width Modulating the current applied to the EMC.

1. Touch-off Torque

The minimum EMC Duty Cycle is based on the
vehicle speed and throttle position.

The TOD receives the TPS signal from the following
sources:

On vehicles equipped with CAN, the TOD receives
the TPS signal from the CAN bus.

2. When Slip Detection

The TOD continuously monitors the front and rear
propeller shaft speeds to detect wheel slip.

3. Wheel Slip Control

When wheel slip is detected the TOD controls the
EMC duty cycle as necessary until the wheel slip
is reduced below the allowable limit. The EMC
Duty Cycle will then be reduced to the Touch-Off
value.

4. Brake/ABS Strategy

When the ABS System is active, the EMC Duty
Cycle is set to a fixed duty cycle (30 %) to aid in
braking without counteracting the ABS System.

5. 4L Strategy

When the system is operating in 4L, the TOD
continues TODTM (operation provided that the
propeller shaft speed is below 175 rpm (5220
pulses/minute)). When the speed increases above
175 rpm, the EMC Duty Cycle is set to the
maximum value (88 %) which applies the maximum
available torque to the front axle.