ECO mode SSANGYONG MUSSO 1998 Workshop Repair Manual

2A-6 SUSPENSION DIAGNOSIS
DAMPING FORCE CONTROL LOGIC
Control Logic that applies on damping force variable suspension is comprised of road sensing driving comfort control
logic to increase driving comfort and vehicle speed sensing control logic, anti-roll control logic and anti-dive control
logic to secure control safety.
LogicSensor
Road Sensing Driving Comfort Control LogicSpeedVertical
Sensor (2.5g)Lateral
Sensor (1g)Axle
Acceleration
Sensor (10g)Brake
Anti-bounce Control Logic
Anti-roll Control Logic
Anti-dive Control Logic
Vehicle Speed Sensing Control Logic
NORMAL CONTROL
Initial Stage
When ignition switch is "ON", system initialization will be performed for approx. 3 seconds. During this time, warning
lamp will stay ON and damping force will be switched to Hard status. After 3 seconds, warning lamp will turn off and
normal control status will be restored.
Normal Damping Force Control Establishment
Damping force will have Soft®Medium®Hard status in AUTO mode and Medium®Hard status in SPORT mode.
When double control items are satisfied at the same time it will be Hard®Medium®Soft in order.
Normal Damping Force Control Release
Control mode release will be "Hard®Medium®Soft"or "Medium®Soft". In case that returned from Hard status to
Medium status during control, it will be done after elapse of setting times. Returning from Medium status to Soft status
will be done immediately without delay.

SUSPENSION DIAGNOSIS 2A-7
SELF-DIAGNOSIS
ECS-ECU indicates ECS circuit defectives to the driver by flickering ECS indicator lamp in the meter cluster 0.5
second of interval if there are defectives.
Code
Body vertical
acceleration
sensor Defects
When sensor output
voltage is less than
0.5-4.5V, more than
4.5V. Judging Conditions01
0.9 - 1.1sec.Set TimeSensor Voltage
³2.0 ± 0.1V
³3.0 ± 0.1V
Release Conditions
0.9 - 1.1sec.Set Time
Body lateral
acceleration
sensorWhen sensor output
voltage is less than
0.55±0.15V, more than
4.45±0.1V. 02
0.9 - 1.1sec.
Sensor Voltage
³2.0 ± 0.1V
³3.0 ± 0.1V
0.9 - 1.1sec.
Stop anti-
bounce ride
control Remedy
Stop anti-roll
control
Axle vertical
acceleration
sensor (wheel G
sensor)When sensor output
voltage is less than
0.5-4.5V, more than
4.5V. 03
0.9 - 1.1sec.
Sensor Voltage
³2.0 ± 0.1V
³3.0 ± 0.1V
0.9 - 1.1sec.
Stop ride
control
Front actuatorCheck step motor
power supply detecting
circuit for open and
short.
check for relative
connectors. 04
0.4 - 0.6sec.
IGN+ SW.
OFF®
ONStop control
after returning
to the previ-
ous mode
Rear actuatorWhen defective detect-
ing circuit has detected
defectives during
output OFF. 05
0.4 - 0.6sec.IGN+ SW.
OFF®
ONStop control
after returning
to the previous
mode
ECU
When ECU does not
work normally. 06
0.4 - 0.6sec.Reset
Stop control
1. Turn the ignition switch ON and if ECS system is normal, ECS indicator lamp will turn on for 3 seconds and then go
off. However if defective, ECS indicator lamp will flicker in the interval of 0.5 second continuously.
2. Identify fault code with Scanner.

5A-2 AUTOMATIC TRANSMISSION
SPECIFICATIONS
MODEL PART NUMBERS AND APPLICATIONS
Transmission
0574-000001 (9)
0574-000002 (8)
0574-000004 (10)
0574-000005 (7)Torque Converter
179K
160K
160K
179KEngine Version
661LA
E32
662LA(Turbo)
E23
MODEL SPECIFICATIONS
Application
Torque Converter
Mean diameter of fluid circuit
Maximum torque multiplication
Stall speed (rpm)
0574-000001 (D23LA)
0574-000002 (E32)
0574-000004 (D29LA)
0574-000005 (E23)
0574-000020
0574-000021
Gear Ratios
First
Second
Third
Fourth
Reverse
Lubricant
Type
Capacity
Dry System
Service Refill
Gear Train End Float
Gear Set Pinion End FloatDescriprtion
260
2.0 : 1
2100 - 2250
2050 - 2250
2100 - 2200
1800 - 2100
2.741 : 1
1.508 : 1
1.000 : 1
0.708 : 1
2.429 : 1
Castrol TQ95 or other approved fluid
9.0 Litres (approx)
4.5 Litres (approx)
0.50 - 0.65 mm
0.10 - 0.50 mm DWMC P/NO
36100-05420 (1)
36100-05430 (1)
36100-05410 (1)
36100-05440 (1)

5A-18 AUTOMATIC TRANSMISSION
INTRODUCTION
The BTR Automotive Model 74 Four Speed Automatic Transmission is an electronically controlled overdrive four
speed unit with a lock-up torque converter. The lock-up torque converter results in lower engine speeds at cruise and
eliminates unnecessary slippage. These features benefit the customer through improved fuel economy and noise
reduction. Refer to table 1.1 for details of power, torque and configuration.
Of primary significance is the transmission control unit (TCU) which is a microprocessor based control system. The
TCU utilizes throttle position, rate of throttle opening, engine speed, transmission output speed, transmission sump
temperature, gear selector position and mode selector inputs, and in some applications a ‘kickdown’ switch to control
all shift feel and shift schedule aspects.
The TCU drives a single proportional solenoid multiplexed to three regulator valves to control all shift feel aspects.
The output pressure of this solenoid is controlled as a function of transmission sump temperature to maintain consistent
shift feel throughout the operating range.
Shift scheduling is highly flexible, and several independent schedules are programmed depending on the vehicle.
Typically the ‘NORMAL’ schedule is used to maximise fuel economy and driveability, and a ‘POWER’ schedule is used
to maximise performance. ‘WINTER’ schedule is used to facilitate starting at second gear.
Figure 1.1 details the differences between conventional and electronic transmission control systems.
Max Torque (Nm)
320Configuration
260 mm Torque Converter
Wide Ratio Gear Set
Splined Output for Transfer CaseMin Torque (Nm)
160 Model
M74 4WD
Transmission Table 1.1 - M74 Torque, Power and Configuration

AUTOMATIC TRANSMISSION 5A-21
Downshift Type
RANGE ‘1’ (MANUAL ‘1’):
RANGE ‘2’ (MANUAL ‘2’):
RANGE ‘3’ (MANUAL ‘3’):
RANGE ‘D’ (DRIVE):
RANGE ‘N’ (NEUTRAL):
RANGE ‘R’ (REVERSE):
RANGE ‘P’ (PARK):Inhibited Above
First gear operation only with inhibited engagement as a function of vehicle
speed. Engine braking is applied with reduced throttle.
First and second gear operation with inhibited engagement of second gear, as
a function of vehicle speed. Engine braking is applied with reduced throttle.
First, second and third gear operation with an inhibited third gear engagement
at high vehicle speed. Refer to the vehicle owner’s manual.
Engine braking is applied with reduced throttle.
First, second, third and fourth gear operation. First to second (1-2), first to third
(1-3), second to third (2-3), second to fourth (2-4), third to fourth (3-4), fourth
to third (4-3), fourth to second (4-2), third to second (3-2), third to first (3-1)
and second to first (2-1), shifts are all available as a function of vehicle speed,
throttle position and the time rate of change of the throttle position (forced
downshift). Lockup clutch may be enabled in 3rd and 4th gears depending on
vehicle type. Refer to the owner’s manual.
Rear band applied only, with inhibited engagement as a function of vehicle
speed, engine speed and throttle position. The inhibitor switch allows the en-
gine to start.
Reverse gear operation, with inhibitor engagement as a function of vehicle
speed, engine speed and throttle position. The inhibitor switch enables reverse
lamp operation.
Rear band applied only, with inhibited engagement as a function of vehicle
speed, engine speed and throttle position. The transmission output shaft is
locked. The inhibitor switch allows the engine to start.
Table 2.1 - Gear Selections
DRIVING MODE SELECTOR
The driving mode selector consists of a mode selection switch and indicator light. The driving mode selector is
located on the centre console. See figure 2,1.
The schedules available to be selected vary with vehicle types. Typically the driver should have the option to select
between ‘NORMAL’ , ‘POWER’ or ‘WINTER’ modes.
When ‘NORMAL’ mode is selected upshifts will occur to maximise fuel economy and the indicator lights remain
extinguished. When ‘POWER’ mode is selected upshifts will occur to give maximum performance and the ‘POWER’
mode indicator light is switched on. When ‘WINTER’ mode is selected, starting at second gear is facilitated, the
‘WINTER’ mode indicator light is switched on and the ‘POWER’ mode indicator light is switched off.
Refer to the vehicle owner’s manual for specific modes for each vehicle type.

5A-24 AUTOMATIC TRANSMISSION
Transmission Control Unit(TCU)
The TCU is an in-vehicle micro-processor based transmission management system. It is usually mounted in the
vehicle cabin, under the instrument panel, under the seat, behind the side kick panels or under the floor in the
footwell on the passenger side. Different control units are supplied for different vehicle applications.
The TCU contains:
lProcessing logic circuits which include a central microcontroller and a back-up memory system.
lInput circuits.
lOutput circuits which control external devices such as the variable pressure solenoid (VPS), on/off solenoid
drivers, a diagnostics output and the driving mode indicator light.
The various items which make up the TCU are discussed below.
Processing Logic
Shift schedule and calibration information is stored in an erasable programmable read only memory (EEPROM).
Throttle input calibration constants and the diagnostics information are stored in electrically erasable programmable
read only memory (EEPROM) that retains the memory even when power to the TCU is disconnected.
In operation the software continuously monitors the input values and uses these, via the shift schedule, to determine
the required gear state, At the same time it monitors, via the solenoid outputs, the current gear state. Whenever the
input conditions change such that the required gear state is different to the current gear state, the TCU initiates a
gear shift to bring the two states back into line.
Once the TCU has determined the type of gear shift required the software accesses the shift logic, estimates the
engine torque output, adjusts the variable pressure solenoid ramp pressure then executes the shift.
The TCU continuously monitors every input and output circuit for short or open circuits and operating range. When
a failure or abnormal operation is detected the TCU records the condition code in the diagnostics memory and
implements a limp mode, The actual limp mode used depends upon the failure detected with the object to maintain
maximum driveability without damaging the transmission. In general input failures are handled by providing a default
value. Output failures, which are capable of damaging the transmission, result in full limp mode giving only third or
fourth gear and reverse. For further details of limp modes and memory retention refer to the Diagnostic Section.
The TCU is designed to operate at ambient temperatures between -40 and 85°C . It is also protected against
electrical noise and voltage spikes, however all the usual precautions should be observed, for example when arc
welding or jump starting.
TCU Inputs
To function correctly, the TCU requires engine speed, road speed, transmission sump temperature, throttle position
and gear position inputs to determine the variable pressure solenoid current ramp and on/off solenoid states. This
ensures the correct gear selection and shift feel for all driving conditions.
The inputs required by the TCU are as follows:
lEngine Speed
The engine speed signal is derived from the tachometer signal line, a dedicated sensor or a Controlled Area
Network (CAN).
lRoad Speed
4WD (Diesel) - The shaft speed signal is derived from the speedo sensor located on the transfer case. This signal
is transmitted directly to the TCU.
4WD (Gasoline) - The speedo sensor sends the shaft speed signal to the engine control module (ECM). The
information is then transferred to the TCU via the CAN.
lTransmission Sump Temperature
The transmission sump temperature sensor is a thermistor located in the solenoid wiring loom within the transmission.
This sensor is a typical NTC resistor with low temperatures producing a high resistance and high temperatures

AUTOMATIC TRANSMISSION 5A-27
Shift Lever Position
Manual 1
Manual 2
Manual 3
Drive
Netural
Reverse
ParkResistance (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.

AUTOMATIC TRANSMISSION 5A-31
K-Line
The K-line is typically used for obtaining diagnostic information from the TCU. A computer with a special interface is
connected to the TCU and all current faults, stored faults, runtime parameters are then available. The stored fault
codes can also be cleared.
The K-line can be used for vehicle coding at the manufacturer’s plant or in the workshop. This allows for one TCU
design to be used over different vehicle models. The particular code is sent to the microprocessor via the K line and
this results in the software selecting the correct shift and VPS ramp parameters.
HYDRAULIC CONTROL SYSTEM
The hydraulic controls are located in the valve body, pump body and main case.
The valve body contains the following:
lManual valve,
lThree shift valves,
lSequence valve,
lsolenoid supply pressure regulator valve,
lline pressure control valve,
lclutch apply regulator valve,
lband apply regulator valve,
lS1 to S6, and
lReverse lockout valve.
lThe pump body contains the following:
lPrimary regulator valve for line pressure,
lconverter clutch regulator valve,
lconverter clutch control valve,
lS7,and
lC1 bias valve.
The main case contains the following:
lB1R exhaust valve
The hydraulic control system schematic is shown at figure 3.7.
All upshifts are accomplished by simultaneously switching on a shift valve(s), switching VPS pressure to the band
and/or clutch regulator valve, and then sending the VPS a ramped current. The shift is completed by switching the
regulators off and at the same time causing the VPS to reach maximum . pressure. All downshifts are accomplished
by switching VPS pressure to the band and/or clutch regulator valve and sending a ramped current to the VPS. The
shift is completed by simultaneously switching the regulators off, switching the shift valves and at the same time
causing the VPS to return to stand-by pressure.
The primary regulator valve is located in the pump cover and supplies four line pressures; high and low for forward
gears, and high and low for reverse. This pressure has no effect on shift quality and merely provides static clutch
capacity during steady state operation. Low pressure can be obtained by activating an On/off solenoid with high line
pressure being the default mode.
Torque converter lock-up is initiated by toggling the converter clutch control valve with an On/off solenoid. The actual
apply and release of the clutch is regulated by the VPS via the converter clutch regulator valve. As an additional
safety feature, the lock-up is hydraulically disabled in first and second gear by the bias valve which only supplies oil
to the lock-up solenoid when C1 is applied in third and fourth gears. This prevents the vehicle from being rendered
immobile in the unlikely event of S7 becoming stuck.
The solenoid supply valve provides reference pressure for all the solenoids.

5A-60 AUTOMATIC TRANSMISSION
DIAGNOSIS
DIAGNOSTIC SYSTEM
Recommended Test Equipment and Procedure
The test equipment is designed to be used with the control modules in all vehicles. The components used in the
transmission application are:
lMulti Function Tester, and
lAppropriate vehicle for testing.
Multi Function Tester (MFT)
The MFT is programmed with the special vehicle diagnostic software that allows selection of the unit under test.
The program allows the proper communication to the Transmission Control Unit (TCU).
It then requests information from the user via a menu system to select the required set up.
Examples are viewing codes, clearing error codes, and real-time operation. Set up and operation instructions are
detailed in the user manual.
This equipment can be used by trained personnel such as technicians and mechanics to diagnose electronic and
wiring problems relating to the vehicle transmission. Information that is available includes engine and road (shaft)
speed, transmission oil temperature, throttle position, solenoid/gear status and gear lever position. Current and
stored faults detected by the electronics are also available.
TCU Pin Description
The TCU pin descriptions are listed in table 6.1.1.
The wiring loom pins are shown in figure 6.1.1
Pin
No.
1
2
3
4
5
6
7
8Identification
Common Ground
Do not use
Mode Indicator Lamp -
‘Winter’
Gear Position ‘Park’
Lamp
Gear Position ‘Reverse’
Lamp
Gear Position ‘Neutral’
Lamp
Do not use
Engine Speed Input
Sensor (-Ve)Type
GND
-
OP
OP
OP
OP
-
IPDescription
Main power ground (or the module. Connects
directly to the battery negative terminal.
Indicates ‘WINTER’ mode shift schedule is se-
lected.
Drives the jewel in the instrument cluster to in-
dicate ‘PARK’ gear lever position.
Drives the jewel in the instrument cluster to in-
dicate ‘REVERSE’ gear lever position.
Drives the jewel in the instrument cluster to in-
dicate ‘NEUTRAL’ gear lever position.
Flywheel/Ring gear pulses to indicate engine
speed. 4WD
(Diesel)
O
O
l
l l l
l
4WD
(Gas)
O
O
O
l
l l l
l
l
Table 6.1.1 - TCU Pin Description

5A-64 AUTOMATIC TRANSMISSION
Default Transmission Operating Modes
The TCU relies on accurate information from its inputs and complete control of its outputs to effectively control the
transmission. To ensure that it has both valid inputs and functioning outputs, the TCU carries out both hardware and
software fault detection routines. The TCU will respond to any faults detected by adopting the operating modes which
are detailed below.
The following symptoms of faults are the most obvious results of each fault under ‘normal’ conditions.
There is always the possibility that a fault may not be detected. If undetected fault conditions are present, the
operation of the transmission is difficult to predict.
1 Throttle Fault
lAll shifts will occur as if a nominal throttle (approx. 44%) were applied for shift scheduling.
lAll shifts will be firm as full throttle and hence high engine torque is assumed.
lThe torque converter will be unlocked at all times.
lAll downshifts initiated by the shift lever will occur as though they were ‘automatic’ shifts. That is the engine
braking effect will not occur until near the end of the shift.
lLine pressure will always stay high (solenoid 6 OFF) to cope with assumed high throttle/torque.
If a fault is undetected, the percent throttle is most likely to be interpreted as higher than actual, resulting in late
upshifts, early downshifts, firm shifting and a harsh 3-1 shift when stopping.
2 Throttle Not Learnt Fault
The transmission operates from default throttle calibration values which results in the evaluation of the throttle being
higher (more open) than it is. There(ore at zero throttle settings, the transmission may calculate that sufficient throttle
opening is present to justify high line pressure and switch solenoid 6 to OFF.
Other symptoms are:
a. late upshifts and
b. lock-up maintained at zero throttle when the vehicle speed is sufficiently high.
3 Engine Speed Fault
lAll shifts will be firm because an engine speed corresponding to peak engine torques is assumed.
If a fault is undetected, the engine speed is likely to be interpreted as stalled resulting in soft shifting possibly with an
end of shift bump.
4 Vehicle Speed Sensor Fault
lAll shifts will be controlled by the shift lever with skip downshifts disabled and downshifts only allowed if the
engine speed is low. Fourth gear will be inhibited.
lThe torque converter will be unlocked at all times.
If a fault is undetected, the vehicle is likely to be interpreted as being stationary resulting in first gear operation at all
times. Note that speedometer transducer faults are likely to cause the vehicle’s speedometer to become inoperative.
5 Gear Lever Fault (Inhibitor/PRNDL Switch)
lThe gear lever is assumed to be in the Drive position.
lThe transmission is limited to 2nd,3rd, and R gears only.
lThe rear band will apply at all times when the lever is shifted to P, R or N. (B2 inhibition and reverse lockout
protection is disabled.)
lThe torque converter will be unlocked at all times.
lManually (gear lever) initiated downshifts will not be available.
If a fault is undetected, the gear lever position is likely to be interpreted as being higher than actual. Where Park is the
highest position and Manual 1 is the lowest, the result being the availability of higher gears than selected by the gear
lever.