1998 SSANGYONG MUSSO 4WD

5D2-6 TRANSFER CASE (TOD)
Input/Output diagram
TOD control unit and main wiring harness is linked by 30 pin
connector. Each pin joins with switche and actuator whose
details refer to the below diagram.
Battery Power
Ignition ON/OFF
Position Encoder 1
Position Encoder 2
Position Encoder 3
Position Encoder 4
4H / 4L Switch Signal
A/T “N” Position Signal
Speed / TPS Supply
Front Speed Sensor Input
Rear Speed Sensor Input
ABS Operation Signal
Brake Switch Signal
4
5
27
10
28
30
9
24
16
11
29
25
26
19
CAN H
CAN L
Shift Motor output port
(LO-HI)
Shift Motor output port
(HI-LO)
EMC
'4L' Indicator
Position Return
'4WD CHECK' IND
TPS/speed Sensor Ground
(Speed / TPS Return)
2
1
3
21
6
7
13 15
14
K-Line20 22
23
17
18

TRANSFER CASE (TOD) 5D2-7
1. K-LINE : Communication line for coding and diagnosis with SCANNER.
Classification of Pin No.
ClassificationPin No. Pin NameDescription
Power Supply17,18Ground
TOD control unit ground
4,19Battery
TOD control unit battery supply : (Fuse No 13,20A)
5IgnitionIgnition ON / OFF
27Position 1
Position encoder 1 : check of shift motor position
10Position 2
Position encoder 2 : check of shift motor position
28Position 3
Position encoder 3 : check of shift motor position
30Position 4
Position encoder 4 : check of shift motor position
94H/4L SwitchTransfer case mode input
24Auto T/M Neutral
Check of neutral gear position in Auto T/M
16Speed5V supply (TPS / speed sensor)
11Front Speed
Front speed sensor signal input Signal Input
29Rear Speed
Rear speed sensor signal input
25ABS Operation
ABS ON / OFF
6Position Return
Position encoder ground
13Speed / TPS ReturnGround for speed sensor / TPS
22CAN-LCAN bus low line
23CAN-HCAN bus high line
2,15Motor LO-HIMotor output port
- LO to HI : join with battery
- HI to LO (or motor brake) : join with ground
1,14Motor HI-LO
Motor output port
- HI to LO : join with battery
- LO to HI (or motor brake) : join with ground
3EMCTOD output
Signal Output
214L IlluminationIlluminates “4L” indicator
7Diagnosis Display
4WD check lamp illuminator
- Upon defect ; Ground circuit
20K-LINE1)Diagnosis

5D2-8 TRANSFER CASE (TOD)
Position Code 1/2/3/4
111 0
1010
0010
0000
111 0
Initial Operation of TOD Control Unit
When ignition “ON”, “4L” and "4WD check" lamps illuminates
for 0.6second to check bulb in instrument panel, then perform
diagnosis of system.
Position Encoder
The Position Encoder is used by the TCCU to determine the
position of the Shift Motor. Each motor position is identified by
a position code as shown.
Notice
1. All other position codes are invalid
2. Position Input Open Circuit (> 4.5V) = 1
3. Position Input shorted to Speed/Position Return (< 0.5V) = 0
Motor Position
Left Stop
Left of High
High
Right of High
Zone 1Position Code 1/2/3/4
1001
0001
0101
0100Motor Position
Neutral
Zone 2
Low
Right Stop

TRANSFER CASE (TOD) 5D2-11
4. Electric Shift Default Mode
If the motor fails to reach its destination, the TCCU will attempt the following (in order):
a. The TCCU will wait 3 seconds then attempt the shift again.
b. If the second attempt to reach the destination fails the TCCU 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.
c. If the attempt to return to the original position fails, the TCCU 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.
d. 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.
TODTM System Operation
The TODTM System is responsible for distributing torque between the front and rear axles. The TCCU monitors the
propshaft 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 TCCU receives the TPS signal from the following sources:
On vehicles equipped with CAN, the TCCU receives the TPS signal from the CAN bus.
2. When Slip Detection
The TCCU continuously monitors the front and rear propshaft speeds to detect wheel slip.
3. Wheel Slip Control
When wheel slip is detected the TCCU 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 TCCU continues TOD
TM (operation provided that the propshaft 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.

TRANSFER CASE (TOD) 5D2-15
DIAGNOSIS
While the TCCU is active it periodically monitors its inputs and outputs. If a fault is detected the “4WD CHECK” lamp
is illuminated and a fault code is stored in the TCCU memory.
When requested, fault codes are downloaded to a diagnostic connector (K-line) serial communications using SCAN-
100.
DIAGNOSTIC TESTS
1.TCCU Internal Function
When the Ignition is turned on the TCCU tests its ROM and RAM. If there is a fault, the TCCU immediately resets
itself and re-tests the ROM and RAM. If the fault persists the TCCU continues to reset and re-test until the fault is
corrected or the ignition is turned off. All TCCU functions are inhibited until the fault is corrected. The “4WD
CHECK” lamp is not illuminated if there is a ROM or RAM fault.
If the ROM/RAM passes the EEPROM memory is tested. If there is a fault the “4WD CHECK” lamp is illuminated
and the TCCU continues to operate using the default calibration data stored in ROM. Fault codes are not stored
when there is an EEPROM fault.
An EEPROM fault can only be cleared by cycling ignition off-on.
2.Shift Motor Assembly Test
If the TCCU detects a shift motor or position encoder fault continuously for one second the ‘4WD CHECK” lamp is
turned on and the appropriate fault code is stored in memory.
a. A shift motor fault when the motor is off is defined as follows:
Motor H-L shorted to Ground
Motor L-H shorted to Ground
Motor open circuit
b. A shift motor fault when the motor is energized is defined as follows:
Motor H-L shorted to Ground
Motor L-H shorted to Ground
Motor H-L shorted to Motor L-H
Motor open circuit
c. A position encoder fault is defined as follows:
Any position code which does not correspond to the valid 9 codes.
A short to ground on any of the encoder lines.
d. If no shifts are in progress when a failure occurs the TCCU will not respond to any shift commands.
e. If a shift command has been received, but not acted upon when a failure occurs the TCCU will cancel the
command and not respond to any subsequent shift commands.
f. If a shift command is in progress when an invalid position code is confirmed it will be halted and the TCCU will
turn the motor toward the high position. Afterwards the TCCU will not respond to any shift commands.

5D2-16 TRANSFER CASE (TOD)
g. If the shift motor/position encoder assembly failure (other than a motor failure which occurs when the motor is
energized) recovers continuously for one second the TCCU will function normally. The “4WD CHECK” lamp is
turned off but the fault code will remain in memory.
h. A motor failure (i.e. open or short circuit) which occurs when the motor is energized can only be cleared by
cycling the ignition off-on.
3. Front Speed Sensor Test
If a Front Speed Sensor fault is detected continuously for 0.5 second the “4WD CHECK” lamp is illuminated. The
TCCU then responds as follows:
a. If the system is in High Range the TCCU uses the Rear Speed Sensor to determine the EMC Touch Off level
and wheel slip control is suspended.
b. If the system is in Low Range, the EMC Duty Cycle is set to maximum (independent of vehicle speed) until the
system is shifted out of 4L.
c. All Electric Shift activity is halted until the Ignition is cycled. If a shift is in progress it will be completed.
If the Front Speed Sensor recovers continuously for O.5 second the TCCU will function normally. The “4WD
CHECK” lamp is turned off but the fault code will remain in memory.
4. Rear Speed Sensor Test
If a Rear Speed Sensor fault is detected continuously for 0.5 second the “4WD CHECK” lamp is illuminated. The
TCCU then responds as follows:
a. If the system is in High Range the TCCU uses the Front Speed Sensor to determine the EMC Touch Off level
and wheel slip control is suspended.
b. If the system is in Low Range, the EMC Duty Cycle is set to maximum (independent of vehicle speed) until the
system is shifted out of 4L.
c. All Electric Shift activity is halted until the Ignition is cycled. If a shift is in progress it will be completed.
If the Rear Speed Sensor recovers continuously for 0.5 second the TCCU will function normally. The “4WD
CHECK” lamp is turned off but the fault code will remain in memory.
5. Both Speed Sensor Faulty
If both the Front and Rear Speed Sensors are faulty continuously for 0.5 seconds the “4WD CHECK” lamp is
illuminated. The TCCU then responds as follows:
a. If the system is in High Range the TCCU sets the EMC Touch Off level based on a vehicle speed of 0 and wheel
slip control is suspended.
b. If the system is in Low Range, the EMC Duty Cycle is set to maximum until the system is shifted out of 4L.
c. All Electric Shift activity is halted until the Ignition is cycled. If a shift is in progress it will be completed.
If both Speed Sensors recover continuously for 0.5 second the TCCU will function normally. The “4WD CHECK”
lamp is turned off but the fault code will remain in memory.
6. EMC Test
The EMC is tested for open circuit or short circuit to ground. If a fault is detected continuously for 0.8 second the
“4WD CHECK” lamp is turned on and all TODTM activity is halted.
If the EMC recovers continuously for 0.8 second the TCCU will function normally. The “4WD CHECK” lamp is
turned off but the fault code will remain in memory.

TRANSFER CASE (TOD) 5D2-21
DIAGNOSIS
Malfunction interior TOD control unit ; fault code
1714
lPhenomenon
1. When ignition “ON”, “4WD CHECK” lamp illuminates
continuously.
2. On diagnosis by SCAN-100, it displays fault code “1714”.
lCause ; Error of EEPROM checksum in TOD control unit
Test Stage / Contents
Result
Stage Test Contents and ProcedureSpecified Value
/Yes/NoCountermeasure
Check power supply for TOD control unit.
1. Disconnect 30 pin connector from TOD control unit.
2. Ignition “ON”.
3. Using multi-tester, measure voltage between pin 5(+)
and 17/18 (-).
- Specified value
- Measured value is within specified range ?11-14 Vdc
Ye s
NoPerform A2 stage
Perform A3 stage
Check connection status in TOD control unit connector.
1. Check connection status.
- Is it connected exactly?
2. In case of mal-connection, connect tightly then perform
the follows.
a. Delete fault code using Scan-100.
b. Ignition “OFF”.
c. Ignition “ON”.
d. Diagnose by Scan-100.
- Does it display fault code “1714”?Ye s
No
Ye s
No
Check short of 10A fuse (fuse No.20).
1. Detach No.20 fuse from engine room fuse box.
2. Check the existence of short.
- Is fuse normal? Yes
No
Check ground of TOD control unit.
1. Ignition “ON”.
2. Check voltage between 4/19 (+) pin and 17/18 (-)
using multi-tester (keep connection status).
- Specified value (battery is good)
- Measured value
3. Check short between 17/18 pin and body after
disconnect 30 pin connector.
- Is resistance "¥"?12Vdc (battery
voltage)
Ye s
No
Ye s
No A1
A2
A3
A4
Perform A3 stage
Perform A2 stage
Perform A3 stage
Normal system
Perform A4 stage
Replace fuse, then
perform A1 stage
Perform A4-3 stage
Replace TOD control
unit
Repair ground wiring
Ground is O.K.,
perform A5 stage

5D2-22 TRANSFER CASE (TOD)
Check function of TOD control unit.
1. Even A1, A2, A3 and A4 test, if you could not find defect,
it is required to replace TOD control unit on basis of
below phenomena.
a. ”4WD CHECK” lamp illuminates continuously when
ignition “ON”.
b. Shift is not possible even 4H/4L switch operation.
c. Upon diagnosis by Scan-100, it displays on
“impossible communication with TOD control unit”
or fault code “1714, 1715, 1716”.
- Do occur the above defects? Yes
NoReplace TOD control
unit
Normal system A5Test Stage / Contents
Result
Stage Test Contents and ProcedureSpecified Value
/Yes/NoCountermeasure