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1. OVERVIEW
▶DC 5-Speed Automatic Transmission
DCAG 5-speed automatic transmission is an electronically controlled 5-speed transmission with a
lockup clutch in the torque converter. The ratios for the gears are realized by three planetary gear sets.
The 5th gear is designed with a step-up ratio of 0.83 as an overdrive. The selector lever is controlled by
electronically and mechanically. The gears are shifted by the corresponding combination of three
hydraulically actuated multiple-disc brakes, three hydraulically actuated multiple-disc clutches and two
mechanical one-way clutches. This electronically controlled automatic transmission adjusts the
operating pressure to provide proper shifting in relation to engine power. This function improves shifting
quality significantly. And, the driver can select "S" (Standard) mode or "W" (Winter) mode according to
the driving conditions. This automatic transmission provides two gears even during reverse driving. The
internal sensors and controls are connected to TCU by cylindrical 13-pin connector.
DCAG 5-speed automatic transmission offers the following advantages:
Improved shifting quality
More gears
Extended working life and reliability
Reduced fuel consumption 1.
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4.
DC A/T Assembly Number
(With T/Converter)
A/T Serial Number
DC A/T Variant Number 1.
2.
3.DC A/T Assembly Number
(With T/Converter)
Base model AT type
A/T Serial Number 1.
2.
3.
09-74891-01
3. PRECAUTIONS
The warning lamp flashes and warning beep sounds when the ESP is operating
When the ESP operates during vehicle movement, the ESP warning lamp on the instrument
panel flashes and beep comes on every 0.1 second. The ESP system is only a supplementary
device for comfortable driving. When the vehicle exceeds its physical limits, it cannot be
controlled.
Do not rely on the system. Keep on the safe driving.
Feeling when ESP is working
When the ESP system activates, the feeling can be different depending on vehicle driving
conditions.
For example, you will feel differently when the ESP system is activated during the ABS is
operating with the brakes applied and when the brakes are not applied on a curve.
If the ESP system operates when the brake is applied, the brake pressure will be increased on
the corresponding wheel which already has braking pressure for the ESP controls.
Noise and vibration that driver feels when ESP system is operating
The ESP system may transfer noise and vibration to the driver due to the pressure changes
caused by the motor and valve operations in a very short period of time. And, keep in mind that
the output and vehicle speed could be decreased without rpm increase due to the ASR function
that controls the engine power. -
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ARP Operation
During the ARP operation, vehicle safety (rollover prevention) takes the first priority and thus,
stronger engine control is in effect. Consequently, the vehicle speed decreases rapidly, so the
driver must take caution for the vehicle may drift away from the lane. -
09-94891-01
1. ESP (Electronic Stability Program)
As the single-track vehicle model used for the calculations is only valid for a vehicle moving forward,
ESP intervention never takes place during backup.
The ESP system includes the ABS/EBD and ASR systems allowing the system to be able to operate
depending to the vehicle driving conditions.
1) Overview
For example, when the brakes are applied during cornering at the speed of 100 km/h, the ABS will
operate at the same time the ASR or ABD systems operate to reduce the power from the slipping
wheel. And when yaw rate sensor detects the rate exceeding 4 degree/seconds, the ESP system
is activated to apply the brake force to the corresponding wheel to compensate the yaw moment
with the vehicle stability control function. This may cause a problem in vehicle control system due
to multi-operation of systems, thus there is a priority as below:
TCS (ASR or ABD) > ESP > ABS (This is subject to the driving and vehicle conditions.)
09-194891-01
4) ARP (Active Roll-Over Protection)
The ARP (Active Roll-over Protection) system is a safety assistant device that minimizes, by controlling
brakes and the engine, the physical tendency of the vehicle rollover during sharp lane changes or U-
turns. For the system, software is added to the existing ESP system and no additional device or switch
is needed. One must note that the ARP system, just as general assistant devices including the ABS, is
only a safety assistant device using the ESP system and its function is useless when the situation
overcomes the physical power. Following picture shows how the ARP compensates the vehicle
position by varying each wheel's braking power to overcome the physical tendency of the vehicle
rollover during sharp turns.
The vehicle driving condition is controlled by the internally programmed logic according to the input
signals from wheel speed sensor, steering angle sensor and lateral sensor.
09-214891-01
4. SCHEMATIC DIAGRAM
When equipped with ABS, the braking force at each wheel will be controlled with 3-channel 4-sensor
method. And when equipped with ESP, 4 wheels will be controlled independently with 4-channel
method. (When controlling ABS system only, it will be operated with 3-channel method.) When
compared to the vehicle equipped with ABS/EBD only, the internal hydraulic circuit has a normally-open
separation valve and a shuttle valve in primary circuit and in secondary circuit. When the vehicle brakes
are not applied during engine running or when applying the non-ABS operating brakes, the normally-
open separation valve and the inlet valve are open, whereas the normally-closed shuttle valve and the
outlet valve are closed. When the ESP system is operating, the normally-open separation valve will be
closed by the solenoid valve operation and the hydraulic circuit will be established by the shuttle valve.
Then, the inlet and outlet valves will be
closed or open depending on the braking pressure increase, decrease or unchanged conditions.
▶The warning lamp comes on and warning beep sounds when the ESP is operating
Driving feeling when the ESP is operating ▶
▶Noise and vibration that driver senses when the ESP is operating
1) Hydraulic Circuit Diagram
When the ESP operates during vehicle movement, the ESP warning lamp on the instrument panel
flickers and beep comes on every 0.1 second. The ESP operation shows that the vehicle stability is
extremely unstable and it is used to warn the driver. The ESP system is just a supplementary system
for the vehicle motion and it cannot control the vehicle when it exceeds the physical limits. Do not
solely rely on the system but be advised to drive the vehicle safely.
When the ESP system activates, the driving feeling can be different depending on vehicle driving
conditions. For example, you will feel differently when the ESP system is activated during when ABS
is operating with the brakes applied and when brakes are not applied on a curve. Thus, the ESP
system would make the driver feel more abruptly when the brakes are applied during the ESP
system activation.
The ESP system may transfer noise and vibration to the driver due to the pressure changes caused
by the motor and valve operations in a very short period of time. Extreme cornering will trigger the
ESP operation and this will make the driver feel noise and vibration due to sudden brake application.
Also, the ESP system controls the engine output. So, the driver may notice the engine output
decrease even when the accelerator pedal is being applied.
09-22
(1) Hydraulic Circuit Diagram
When compared to the vehicle equipped with ABS/EBD only, the internal hydraulic circuit has a
normally-open separation valve and a shuttle valve in primary circuit and in secondary circuit.
When the vehicle brakes are not applied during engine running or when applying the non-ABS
operating brakes, the normally-open separation valve and the inlet valve are open, whereas the
normally-closed shuttle valve and the outlet valve are closed.
When the ESP system is operating, the normally-open separation valve will be closed by the solenoid
valve operation and the hydraulic circuit will be established by the shuttle valve. Then, the inlet and
outlet valves will be closed or open depending on the braking pressure RISE, HOLD or DUMP
conditions.
10-74891-01
2) EBD (Electronic Brake Force Distribution) System
▶System description
As an add-on logic to the ABS base algorithm, EBD works in a range in which the intervention
thresholds for ABS control are not reached yet.
EBD ensures that the rear wheels are sensitively monitored for slip with respect to the front axle. If slip
is detected, the inlet valves for the rear wheels are switched to pressure hold to prevent a further
increase in pressure at the rear-wheel breaks, thus electronically reproducing
a pressure-reduction function at the rear-wheel brakes.
ABS features an enhanced algorithm which includes control of the brake force distribution between the
front and rear axles. This is called Electronic Brake Distribution. In an unloading car condition the brake
efficiency is comparable to the conventional system but for a fully loaded vehicle the efficiency of the
EBD system is higher due to the better use of rear axle braking capability.
▶Advantages
Elimination of conventional proportioning valve EBD utilizes the existing rear axle wheel speed
sensor to monitor rear wheel slip.
Based on many variables in algorithm a pressure hold, increase and/or decrease pulsetrain may
be triggered at the rear wheels insuring vehicle stability.
Vehicle approaches the ideal brake force distribution (front to rear).
Constant brake force distribution during vehicle lifetime.
EBD function is monitored via ABS safety logic (conventional proportioning valves are not
monitorable). -
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3) Important Notice
The modulators for production line are not filled with the brake fluid (dry type). But, for after service, they
are filled with the brake fluid (wet type).
Make sure to keep the procedures in service manual when bleeding the air from the brake lines.
Be familiar with the lamp ON conditions to provide the correct information and reliability to customers.
ECU monitors the valve and motor for ABS when the vehicle speed approaches 5 km/h. At this time,
you can hear the clattering noise. 1.
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