Circuit ISUZU KB P190 2007 Workshop Repair Manual

CONSTRUCTION AND FUNCTION 7A1-7

TRANSMISSION CONTROL MODULE (TCM) PERIPHERAL CIRCUIT

































































Figure 4. TCM Peripheral Circuit



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7A1-8 CONSTRUCTION AND FUNCTION
STRUCTURE AND FUNCTION OF COMPONENT
TORQUE CONVERTER (WITH LOCK-UP FUNCTION)
• The torque converter is a device for transmitting the engine torque to the transmission. It transmits power
by means of oil when the lock-up clutch is disengaged, and by means of a lock-up clutch when it is
engaged.
• The torque converter is of the symmetrical, three-element, single-stage, two-phase type.
• As shown in the drawing, the symmetrical three-elements refer to three elements (components) consisting
of impeller (1), turbine (2) and stator (3) that are arranged symmetrically (figure 5).
• "Single-stage" means that there is only one turbine as an output element; "two-phase" means that the
pump impeller acts as a torque converter when the turbine speed is comparatively low, and as a fluid
coupling when the speed is high.


















1. Pump Impeller
2. Turbine Runner
3. Stator














1. Pump Impeller
2. Turbine Runner
3. Stator
4. Converter Cover
5. One-way Clutch
6. Lock-up Piston
7. Torsion Damper

Figure 5. Torque Converter
Figure 6. Construction of Torque Converter

Lock-up mechanism
• "Lock-up" refers to a fixed state of the lock-up clutch inside the torque converter and thus connects the
engine directly to the transmission.
• The hydraulic pressure for the lock-up control is supplied from two circuits.

When the lock-up clutch is disengaged (Figure 7) • When the lock-up is disengaged, the torque converter operating pressure is supplied from the oil pass age
(A) to between the cover and the lock-up piston, and separates the lock-up piston clutch facing and
converter cover.
• As a result, the engine drive power is transmitted from the converter cover to the pump impeller, to the
ATF and to the turbine. The torque converter functions as a fluid connector in this condition.
• The torque converter operating pressure is supplied from oil passage (A), and passes through oil passage
(B).

When the lock-up clutch is engaged (Figure 8) • When the lock-up is engaged, the torque converter operating pressure is supplied from oil passage (B) to
the oil pump impeller, the turbine, and then to the stator side. The oil between the lock-up piston and
converter cover is drained.
• Since the force acting on the right side of the lock-up piston is greater than the force on the left side, it
connects the lock-up piston clutch facing with the converter cover, thereby increasing the transmission
efficiency.

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7A1-14 CONSTRUCTION AND FUNCTION
CONTROL VALVE
• Employing the direct electronic control (Direct Electronic Shift Control: DESC) for the clutch pressure has
simplified the oil pressure circuit, reduced the number of functional components and made the control
valve compact.
• The control valve body is divided into the upper body and the lower body. All solenoids, the oil pressure
switch and the ATF thermo sensor are installed to the lower body.
• Three-way valve type solenoids providing high responsibility are employed. Some of the solenoids are
switched between ON and OFF, and others repeat ON and OFF at 50Hz (duty cycle system).
Functionally, some supply output pressure when power is not supplied, and others drain the output
pressure.
• When the solenoid is driven based on the signal from the TCM, the oil pressure is changed.


Figure 22. Construction of Valve Body

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CONSTRUCTION AND FUNCTION 7A1-21
INHIBITOR SWITCH
• The inhibitor switch is installed on the right side of the transmission main unit to detect the select lever
position.
• The inhibitor switch is connected with the starter SW circuit. The engine cannot be started when the
select lever is at any position other than the P and N position.
• By moving the select lever, the combination of the inhibitor switch pins is changed. The current position of
TCM is detected based on the combination of the pins.
10 7 3 2 4 8 5 1 9 6
P
R
N
D
3
2
L





6345
10987
21



Terminal Assembly Inhibitor Switch

Figure 36. Pin Assignment Figure 37. Location of Inhibitor Switch


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7A1-26 CONSTRUCTION AND FUNCTION
CONTROL MECHANISM
CONTENT OF FUNCTION AND CONTROL
Item Description
Line pressure control TCM issues a signal according to vehicle travel, engine load and other conditions, which
drives the ON/OFF type line pressure solenoid to switch the line pressure to high or low
pressure.
The line pressure solenoid is switched to the low pressure side when the solenoid is turned
ON (power supplied) and to the high pressure side when turned OFF (no power supplied).
In the forward travel position (D, 3, 2, L position), the line pressure decreases lower than
that in the P, N, and R position through the oil pressure circuit.


Gear shift control The TCM issues a shift solenoid drive signal based on the traveling mode switch, inhibitor
switch, the vehicle speed, the APP opening and other input signals, to control the optimum
gear position automatically.
Shift features have been set up to the TCM; the normal mode is suited to normal travel, and
the power mode is used when the vehicle is loaded or the speed accelerated.
In addition, shift features used only for high oil temperature, hill climbing, and downward
travel have been set up to the TCM. These are automatically switched depending on the
travel conditions.
W hen the oil temperature is low (10°C or less), shifting up from the third speed to the fourth
speed is prohibited by the gear shift control.


Shift pattern selection
control
The TCM selects the following shift pattern according to a vehicle condition.

Selection
Priority Shift Pattern 3rd Start
Lamp Power Drive
Lamp
High High Temperature OFF OFF
3rd Start ON
4L
Power SW Off
OFF
Down Slope
Power SW On
Power ON

Up Slope
Low Normal



OFF
OFF
- High temperature mode -
High temperature mode setting condition
ATF temperature: 122 °C or more
Above condition is met for 10.16 seconds.
High temperature mode cancel condition
ATF temperature: 115 °C or less
Above condition is met for 10.16 seconds.

-NOTE-
High temperature mode may be activated with driving conditions other than the setting
conditions stated, in order to protect Automatic Transmission from thermal damage.

- 3rd start mode -
3rd start mode setting condition
3rd start switch: On → Off (Pushed)
Vehicle speed: 11km/h or less.
ATF temperature: 115 °C or less.
APP position: 8% or less.
Select lever position: D position
Above conditions are all met at the same time.




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7A1-30 CONSTRUCTION AND FUNCTION
LINE PRESSURE CONTROL
• The TCM drives the ON/OFF type line pressure solenoid based on the APP opening, vehicle speed,
turbine rotational speed, ATF temperature and shift position signal. The ON/OFF type line pressure
solenoid is actuated, and switches the line pressure to a high or low pressure number appropriate to the
situation.
• The line pressure generated by the oil pump acts on the point A of the pressure regulator valve. When
the pressure control solenoid is turned ON by the signal from the TCM, the solenoid pressure does not
act. The line pressure is adjusted to match the spring force acting on the right side of the pressure
regulator valve.
• When the pressure control solenoid is turned OFF, the solenoid pressure acts so that the line pressure is
adjusted to match the spring force acting on the right side of the pressure regulator valve.
• As a result, the line pressure is adjusted to be low when the pressure control solenoid is ON and to be
high when the pressure control solenoid is OFF.
• In position D, 3, 2 and L, the line pressure through the oil pressure circuit acts onto the point B of the
pressure regulator valve. The pressure regulator valve moves so as to increase the pressure to be
drained, so that the line pressure is adjusted to be lower than the P, N, and R position by the difference of
area at the point B.




Figure 50. Line Pressure Control

LOCK-UP CONTROL
• The lock-up solenoid adjusts the pressure and controls the lock-up based on the pre-set lock-up point,
according to the vehicle speed, APP opening, engine rotations, turbine rotations and ATF temperature
input signal, based on the signal from the TCM.
• Smooth lock-up control is employed to engage or disengage the clutch smoothly at the time of lock-up on
or off.
• When the oil temperature is low (20°C or less), lock-up is disengaged even though the vehicle is at the
lock-up speed.
• The lock-up is disengaged also when the APP is closed.
• When the TCM determines the lock-up engagement, the DUTY ratio to supply power to the lock-up
solenoid is gradually increased (5% to 95%) and the oil between the lock-up piston and converter cover is
gradually drained.

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CONSTRUCTION AND FUNCTION 7A1-35
CONTROL CIRCUIT BLOCK DIAGRAM



Speed sensor
Turbine sensor
Brake switch
Inhibitor switch
Power drive, 3rd start
switch
ATF oil thermo sensor
High clutch oil pressure
switch
2-4 brake oil pressure
switch
Low & reverse brake oil
pressure switch
Transfer control module
(4W D Only)



Engine Control Module
(ECM)
Line pressure solenoid
Low clutch solenoid
High clutch solenoid
2-4 brake solenoid
Low & reverse brake
solenoid
Lock-up solenoid
ATF temperature
indicator lamp
Speed meter (2W D
Only)
Power, 3rd start indicator
lamp
Check trans indicator
lamp
Data link connector Self-diagnosis
function



Transmission
Control
Module (TCM)
4L mode
Tachometer
signal output
APP PW M
position signal
output
Figure 54. Control Circuit Block Diagram

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7A1-36 CONSTRUCTION AND FUNCTION
GEAR TRAIN (TRANSMISSION MECHANISM) OPERATION AND
HYDRAULIC CIRCUIT
CONSTRUCTION AND OPERATION
The JR405E consists of two sets of planetary gears, three multiple plate clutches, two multiple plate brakes
and one one-way clutch.





COMPONENT NAME AND FUNCTION
Component Name Symbol Function
Low Clutch L/C Connects the front planetary carrier to the rear
internal gear.
Engaged at 1st, 2nd and 3rd gear.
High Clutch H/C Connects the input shaft to the front planetary
carrier.
Engaged at 3rd and 4th (O/D) gear.
Reverse Clutch R/C Connects the input shaft to the front sun gear.
Engaged at Reverse gear.
Low & Reverse Brake L&R/B Locks the front planetary carrier.
Engaged at L position and Reverse gear.
2-4 Brake 2-4/B Locks the front sun gear.
Engaged at 2nd and 4th (O/D) gear.
Low One-way Clutch L/O.C Allows the front planetary carrier to turn forward
(clockwise) but locks to opposite direction
(counterclockwise).
Operative when accelerating.
Low Clutch Solenoid L/C.S Regulates low clutch pressure.
High Clutch Solenoid H/C.S Regulates high clutch pressure.
Low & Reverse Brake Solenoid L&R/B.S Regulates low & reverse brake pressure.
2-4 Brake Solenoid 2-4/B.S Regulates 2-4 brake pressure.
Lock-up Solenoid L/U.S Regulates lock-up clutch pressure.
High Clutch Oil Pressure SW H/C.P/SW Detects high clutch supply oil pressure.
Low & Reverse Brake Oil Pressure SW L&R/B.P/SWDetects low & reverse brake supply oil pressure.
2-4 Brake Oil Pressure SW 2-4/B.P/SWDetects 2-4 brake supply oil pressure.

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TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-5
Diagnostic Trouble Code (DTC) List
DTC Flash CodeDTC Descriptor
P0560 16 System Voltage Malfunction
P0602 — Control Module Programming Error
P0705 17 Inhibitor Switch Malfunction
P0710 15 Transmission Fluid Temperature Sensor Circuit Malfunction
P0717 14 Input/Turbine Speed Sensor “A” Circuit No Signal
P0722 11 Output Speed Sensor Circuit No Signal
P0727 13 Engine Speed Sensor Input Circuit No Signal
P0731 41 Gear 1 Incorrect Ratio
P0732 42 Gear 2 Incorrect Ratio
P0733 43 Gear 3 Incorrect Ratio
P0734 44 Gear 4 Incorrect Ratio
P0748 35 Line Pressure Solenoid Malfunction
P0753 31 Low & Reverse Brake Duty Solenoid Malfunction
P0758 32 2-4 Brake Duty Solenoid Malfunction
P0763 33 High Clutch Duty Solenoid Malfunction
P0768 34 Low Clutch Duty Solenoid Malfunction
P1120 22 Throttle Position Signal Malfunction
P1750 51 Low & Reverse Brake Fail Safe Valve Malfunction
P1755 52 2-4 Brake Fail Safe Valve Malfunction
P1853 26 Low & Reverse Brake Pressure Switch Malfunction
P1858 27 2-4 Brake Pressure Switch Malfunction
P1860 36 Lock Up Duty Solenoid Malfunction
P1863 28 High Clutch Pressure Switch Malfunction
P1875 25 Ground Return Malfunction

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7A2-8 TRANSMISSION CONTROL SYSTEM (JR405E)
TCM Power, Ground and Serial Data Circuits

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