2007 ISUZU KB P190 brake

CONSTRUCTION AND FUNCTION 7A1-15

Line Pressure Solenoid • The line pressure solenoid is turned ON or OFF according to the signal from the TCM. It switches the
line pressure between high and low pressure.
• While no power is supplied, the solenoid supplies high pressure.

Shift Solenoid • The shift solenoid is of the duty cycle type, which is turned ON or OFF at 50Hz. The ratio of the ON and
OFF time can be freely controlled in the position of 0 - 100%.
• While no power is supplied, the solenoid supplies output pressure.
• The low clutch solenoid adjusts the low clutch pressure, the high clutch solenoid adjusts the high clutch
pressure, the 2-4 brake solenoid adjusts the 2-4 brake pressure, and the low & reverse brake solenoid
adjusts the low & reverse brake pressure respectively.

Lock-up Solenoid • The lock-up solenoid is of the duty cycle type which is turned ON or OFF at 50Hz. The ratio of the ON
and OFF time can be freely controlled in the position of 0 - 100%.
• While no power is supplied, the solenoid drains the output pressure.




Figure 23. Shift Solenoid Figure 24. Lock-up Solenoid

Figure 25. Location of Solenoid


BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

7A1-16 CONSTRUCTION AND FUNCTION
Control Valve Fail-safe Function • To prevent interlocking due to engagement of more than three clutches and brakes at the same time, the
2-4 brake fail-safe valve A and B, and the low & reverse brake fail-safe valve A and B are provided.
• When oil pressure is generated in the high clutch and the low clutch, the 2-4 brake solenoid is turned ON
to drain the oil pressure applied to the 2-4 brake.
• When oil pressure is generated in the high clutch or 2-4 brake, the low & reverse brake solenoid is turned
ON to drain the oil pressure applied to the low & reverse brake.



Oil Pressure Switch • The oil pressure switch detects the condition of the oil pressure supply to the clutch and brake, and then
sends the detection result to the TCM.
• The oil pressure switch is turned ON when the oil pressure reaches the switch working pressure, and
turned OFF when the pressure decreases below the specified value.
• The high clutch oil pressure switch detects the high clutch oil pressure, the 2-4 brake oil pressure switch
detects the 2-4 brake oil pressure, and the low & reverse brake oil pressure switch detects he low &
reverse brake oil pressure respectively.




Figure 27. Oil Pressure Switch Figure 28. Location of Oil Pressure Switch


BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

7A1-18 CONSTRUCTION AND FUNCTION
Terminal Assembly Pin No. Connected to Connected TCMPin No.
6 Line Pressure Solenoid B23
12 Low & Reverse Brake Oil Pressure Switch B12
5 Low & Reverse Brake Duty Solenoid B6
11 Ground Return B22
4 Lock-up Duty Solenoid B17
10 High Clutch Duty Solenoid B8
3 Low Clutch Duty Solenoid B9
9 2-4 Brake Duty Solenoid B7
2 Oil Thermo Sensor B4
8 Oil Thermo Sensor Ground B14
1 High Clutch Oil Pressure Switch B20
7 2-4 Brake Oil Pressure Switch B1


123456
891011127

Terminal AssemblyInhibitor Switch
Figure 31. Pin Assignment Figure 32. Location of Terminal Assembly


BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

7A1-24 CONSTRUCTION AND FUNCTION
BRAKE SWITCH
• The brake switch (1) is installed to the brake pedal (2). When the driver steps on the brake pedal, an
electric signal is sent to the TCM.







TCM A3 +12V
RTW 77ASH000601
Figure 45. Brake Switch
Figure 46. Pin Assignment


MODE SELECT SWITCH
• The mode select switch (2) is installed beside the select lever (1). When the driver selects the PWR or
3rd, an electric signal is sent. It turns ON the indicator lamp in the meter.
• The 3rd START mode can only be used in the D position.












Power 3rd Illumination
Lamp
1 (Illumination)
2 (Ground)
3 (TCM A24)
4 (No Connection)
5 (TCM A11)
6 (Ground)

21
65 4 3
RTW 77ASH000701
Figure 47. Mode Select Switch
Figure 48. Pin Assignment



BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

CONSTRUCTION AND FUNCTION 7A1-25
TRANSMISSION CONTROL MODULE (TCM)
• The TCM is fitted on the side of the brake pedal via two stud bolts.
• The TCM judges the line pressure, gear shifting point and lock-up operation based on electrical signals
from switches and sensors, and sends the appropriate signals to solenoids.





B9 B8 B7 B6 B5 B4 B3 B2 B1 A9 A8 A7 A6 A5 A4 A3 A2 A1
B18 B17 B16 B15 B14 B13 B12 B11 B10 A18 A17 A16 A15 A14 A13 A12 A11 A10
B24 B23 B22 B21 B20 B19 A24 A23 A22 A21 A20 A19
Connect to White Connector Connect to Grey Connector


Figure 49. Pin Assignment

Pin No. Pin Assignment Pin No.Pin Assignment
B1 2-4 Brake Oil Pressure Switch A1 V BATT (Battery Back-up Power Supply)
B2 2 Position Switch A2 P Position Switch
B3 Turbine Sensor A3 Brake Switch
B4 ATF Thermo Sensor A4 3rd Start Indicator Lamp
B5 Ground A5 K-Line Signal (Tech 2 Serial Communication)
B6 Low & Reverse Brake Duty Solenoid A6 No Connection
B7 2-4 Brake Duty Solenoid A7 Engine Speed Sensor
B8 High Clutch Duty Solenoid A8 No Connection
B9 Low Clutch Duty Solenoid A9 No Connection
B10 N Position Switch A10 Vehicle Speed Sensor Out (2W D Only)
B11 D Position Switch A11 3rd START Select Switch
B12 Low & Reverse Brake Oil Pressure Switch A12 4L Mode Switch (4W D Only)
B13 Vehicle Speed Sensor A13 No Connection
B14 ATF Thermo Sensor Ground A14 No Connection
B15 No Connection A15 No Connection
B16 No Connection A16 Accelerator Pedal Position Sensor
B17 Lock-up Duty Solenoid A17 3 Position Switch
B18 Vign (Ignition Power Supply) A18 DIAG Switch (Test Switch)
B19 R Position Switch A19 A/T OIL TEMP Indicator Lamp
B20 High Clutch Oil Pressure Switch A20 CHECK TRANS Indicator Lamp
B21 L Position Switch A21 POW ER DRIVE Indicator Lamp
B22 Ground (Shift Solenoid) A22 No Connection
B23 Line Pressure Solenoid A23 No Connection
B24 Vign (Ignition Power Supply) A24 POW ER DRIVE Select Switch

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

CONSTRUCTION AND FUNCTION 7A1-27
Item Description
3rd start mode reset condition
3rd start switch: On → Off again(Pushed again)
Vehicle speed: 34km/h or more
Select lever position: Other than D position
At least, one of above conditions is met.

- 4L mode -
4L mode setting condition
4L switch: On
Vehicle speed: 5km/h or more
Above conditions are all met at the same time.
4L mode reset condition
4L switch: Off
Vehicle speed: Less than 5km/h
Above conditions are all met at the same time.

- Down slope mode -
Down slope mode setting condition
Brake switch: On
Accelerator pedal condition: Released for 2 seconds or more.
Select lever position: D or 3 position
Vehicle speed: More than 60km/h
Increment of vehicle speed: More than 1km/h per second
Above conditions are all met at the same time.
Down slope mode reset condition
Accelerator pedal condition: Depressed
Select lever position: Other than D or 3 position
At least, one of above conditions is met.

- Power Mode -
W hen the power drive switch is On the shift pattern change is performed by 1 – 4 speed
based on shift diagram set as power pattern .

- Up slope mode -
Up-slope reasoning value is calculated from the average APP angle and the average
acceleration. Otherwise, up-slope reasoning value is calculated from the vehicle speed.
TCM chooses up-slope mode when the former is bigger than the latter.


Lock-up control The lock-up solenoid adjusts the pressure to control the lock-up according to the signal
from the TCM. This signal is based on the vehicle speed, APP opening and other input
signals based on the pre-set lock-up point.
Smooth lock-up control engages and disengages the clutch smoothly at the time of lock-up.
W hen the oil temperature is low (20°C or less), lock-up is prohibited even when the vehicle
is at a lock-up speed.
The lock-up is also disengaged when the APP is closed.
Direct electronic shift
control (DESC)
The duty cycle type solenoid is used for each clutch and brake. The solenoid adjusts the
clutch pressure to suit the engine load and vehicle traveling condition based on the signal
from the TCM. The pressure switch provided in the control valve oil passage sends the oil
pressure condition to the TCM, which controls the disengagement or engagement of the
clutch and brake directly and finely.

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

CONSTRUCTION AND FUNCTION 7A1-29
CONTROL ITEM, INPUT AND OUTPUT

Control item

Item

Line
pressure control
Gear shift
control
Shift
pattern
selection
Lock-up control Direct
electronic shift
control
(DECS)
Learning control
Fail-safe function
Self-
diagnosis function
Speed sensor
Turbine sensor
Engine speed sensor
Brake switch

Inhibitor switch
Mode select switch

4L switch (4W D Only)

ATF thermo sensor
High clutch oil pressure switch

2-4 brake oil pressure switch
Low & Reverse brake oil pressure
switch
Input
Accelerator Pedal position sensor
Line pressure solenoid

Low clutch solenoid

High clutch solenoid

2-4 brake solenoid

Low & Reverse brake solenoid

Lock-up solenoid

Shift pattern indicator lamp

ATF temperature indicator lamp

Output
Check trans indicator lamp



BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

CONSTRUCTION AND FUNCTION 7A1-31
As a result, the lock-up piston is fitted slowly to the converter cover under pressure securing smooth lock-
up engagement.


Figure 51. Lock-up Control

DIRECT ELECTRIC SHIFT CONTROL (DESC)
Feature
• Based on each switch signal (low & reverse brake pressure, 2-4 brake pressure & high clutch pressure)
and each sensor signal (turbine sensor, speed sensor, engine speed signal & APP position signal), the
duty cycle type solenoid adjusts the clutch pressure to match the engine load and vehicle travel
conditions. Controlling the engagement and disengagement of the clutch and brake pressure is directly
and accurately controlled via TCM, which is different to the previous accumulator type.
Operation
• Instead of the previous system (on/off type of shift solenoid and shift valve), the combination of the duty
cycle type solenoid and the amplifier (Amp) valve are used to adjust the clutch pressure to match the
engine load and vehicle travel conditions, based on the signal from the TCM. Also, the pressure switch
provided in the oil passage of the control valve transmits the oil pressure condition (at that time) to TCM,
enabling the engagement and disengagement control of the clutch and brake to be directly and finely
carried out.
• When the gear is shifted from the 2nd to 3rd, 3rd to 4th (O/D), 4th (O/D) to 3rd and 3rd to 2nd, the clutch
pressures on the engagement side and disengagement side are simultaneously controlled.
As a result, engine racing or clutch drag is prevented which enables a smooth and quick shift response.


BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007