2007 ISUZU KB P190 engine

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-145
Legend1. Oil pump cover
2. Inner rotor
3. Outer rotor
4. Oil pump housing
The oil pump generating oil pressure is a small sized
trochoid gear type oil pump. It feeds oil to the torque
converter, lubricates the power train mechanism, and
feeds the oil pressure to the oil pressure control unit
under pressure. The oil pump is located behind the
torque converter. Since the inner rotor in the oil pump is
fitted with the drive sleeve of the torque converter, it
works using power from the engine.
Legend
1. Pressure regulator valve
2. Outlet
3. Inlet
When the inner rotor in the oil pump rotates,
transmission fluid is sucked in from the oil pan, passed
between the inner rotor, outer rotor and crescent, and
then discharged. This discharged pressure is sent to
the pressure regulator valve in the valve body, and
adjusted as required for operating the transmission.
The flow rate under pressure increases or decreases in
proportion to the number of rotations.
Input Shaft
The input shaft has some oil holes, through which
lubricating transmission fluid is supplied to the torque
converter, the bearings, etc. The input shaft is fitted to
the turbine runner in the torque converter, the reverse &
high clutch drum and the rear sun gear by means of the
spline. Therefore, the engine driving force received by
the torque converter is transmitted to the reverse &
high clutch drum and rear sun gear.
Output Shaft
The output shaft has some oil holes, through which the
lubricating transmission fluid is supplied to the
bearings, the planetary gear unit, etc. The output shaft
transmits the engine driving force from the planetary
gear to the propeller shaft. The front internal gear is
fitted with the rear carrier assembly by spline. The
parking gear is also fitted by spline. By fixing this gear
mechanically, the output shaft is fixed as required when
parking the vehicle.

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-151
The transmission fluid temperature (TFT) sensor is part
of the harness assembly. The sensor is a variable
resistor and it measures the temperature of the
transmission fluid. When the TFT sensor is cold, the
sensor resistance is high. When the transmission fluid
temperature increases, the sensor resistance
decreases. With high sensor resistance, the TCM
detects a high voltage on the signal circuit. With lower
sensor resistance, the TCM detects a lower voltage on
the signal circuit.
If the fluid temperature increases to 135 °C (275 °F), the
TCM illuminates A/T Oil Temp lamp on the instrument
panel cluster. When the fluid temperature deceases
below 125 °C (257 °F), the lamp goes off.
Transmission Range (TR) Switch
Legend 1. Input shaft speed (ISS) sensor
2. Output shaft speed (OSS) sensor
3. TR switch
4. In-line harness connector
The transmission range (TR) switch is connected to the
transmission manual shaft and installed externally to
the transmission case. The selector lever moves the
TR switch position via control cable. The TR switch
relays a signal to the TCM indicating transmission
range position by detecting ignition voltage through an
internal switch. Only one of the seven internal switches
will close for each P, R, N, D, 3, 2 and L position.
Normally, the TCM expects to detect one high voltage
input for each position.
The engine will not crank when the selector lever is at
any position other than the P or N range.
Input Shaft Speed (ISS) Sensor
Legend 1. ISS sensor
2. Reverse & high clutch drum
The input shaft speed (ISS) sensor is located on right-
hand of the transmission case. The ISS sensor is a hall
effect element type sensor, which generates a square
wave signal pulse based on the reverse & high clutch
drum rotational speed (32 pulses per a rotation of the
reverse & high clutch drum that is fitted with the input
shaft by spline). The TCM calculates the turbine speed
by the ISS sensor signal, and uses it to calculate torque
converter slip speed and gear ratio.
3
1
24
P
R
N
D
3
2
L
10732485196
1
2

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

7A2-152 TRANSMISSION CONTROL SYSTEM (JR405E)
Output Shaft Speed (OSS) Sensor
Legend1. OSS sensor
2. Parking gear
The output shaft speed (OSS) sensor is located on
right-hand of the transmission case near the
transmission range switch. The OSS sensor is a hall
effect element type sensor, which generates a square
wave signal pulse based on the parking gear rotational
speed that is connected to output shaft (16 pulses per a
rotation of the parking gear that is fitted with the output
shaft by spline). The TCM calculates the vehicle speed
by the OSS sensor signal, and uses it to determine
appropriate shift points and calculate gear ratio. The
2WD vehicle outputs the vehicle speed signal from the
TCM to the engine control module (ECM) and the
vehicle speed meter via output signal line.
Transmission Control System Description
Transmission Control Module (TCM) Service
Precautions
Important:
To avoid shock and possible serious injury, DO NOT
touch the terminals. When disconnecting the harness
connectors, always turn OFF the ignition switch or
disconnect the battery cable.
The transmission control module (TCM) is designed to
withstand normal current draws associated with vehicle
operation. Avoid overloading any circuit. When testing
for opens and shorts, do not ground or apply voltage to
any of the TCM circuits unless instructed to do so. In
some cases, these circuits should only be tested using
a DMM. The TCM should remain connected to the TCM
harness. The TCM is located next to brake pedal via
mounting bracket. The TCM mainly controls the
gearshift system control and on-board diagnostic for
transmission control. The TCM constantly observes the
information from various sensors. The TCM controls
the systems that affect vehicle performance. The TCM
performs the diagnostic function of the system. The
TCM can recognize operational problems, alert the
driver through the check trans lamp, and store
diagnostic trouble codes (DTCs). DTCs identify the
system faults to aid the technician in making repairs.
1
2

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-153
TCM Input & Output
TCM Voltage Description
The TCM supplies a buffered voltage to various
switches and sensors. The TCM can do this because
resistance in the TCM is so high in value that a test
lamp may not illuminate when connected to the circuit.
An ordinary shop voltmeter may not give an accurate
reading because the voltmeter input impedance is too
low. Use a 10-megaohm input impedance DMM, to
ensure accurate voltage readings. The input and/ or
output devices in the TCM include analog-to-digital
converters, signal buffers, counters, and special
drivers. The TCM controls most components with
electronic switches which complete a ground circuit
when turned ON.
Electrostatic Discharge Damage
Electronic components used in the TCM are often
designed to carry very low voltage. Electronic
components are susceptible to damage caused by
electrostatic discharge. By comparison, as much as
4,000 volts may be needed for a person to feel even
the zap of a static discharge. There are several ways
for a person to become statically charged. The most
common methods of charging are by friction and
induction.
• An example of charging by friction is a person sliding across a vehicle seat.
Important: To prevent possible electrostatic discharge
damage, follow these guidelines:
• Do not touch the TCM connector pins or soldered components on the TCM circuit board.
• Do not open the replacement part package until the part is ready to be installed.
• Before removing the part from the package, ground the package to a known good ground on
the vehicle.
• If the part has been handled while sliding across the seat, while sitting down from a standing
position, or while walking a distance, touch a
known good ground before installing the part.
• Charge by induction occurs when a person with well insulated shoes stands near a highly charged
object and momentarily touches ground. Charges
of the same polarity are drained off leaving the
person highly charged with opposite polarity.
Sensor inputs
Input shaft speed (ISS) sensor
Output shaft speed (OSS) sensor
Transmission fluid temperature (TFT) sensor
Accelerator pedal position signal (via ECM)
Engine speed signal (via ECM)
Switch inputs
Low & reverse brake transmission fulid
pressure (TFP) switch
2-4 brake transmission fulid pressure (TFP)
switch
High clutch transmission fulid pressure (TFP)
switch
Transmission range (TR) switch
Power drive switch
3rd start switch
Brake pedal switch
4WD low gear signal (via TCCM)
TCM
Solenoid valve outputs
Pressure control (PC) solenoid valve
Torque converter clutch (TCC) solenoid valve
Low & reverse brake solenoid valve
2-4 brake solenoid valve
High clutch solenoid valve
Low clutch solenoid valve
Other outputsVehicle speed signal (2WD only)
CommunicationScan tool
Lamp control outputsCheck trans lamp
A/T oil temp. lamp
Power drive lamp
3rd start lamp

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

7A2-154 TRANSMISSION CONTROL SYSTEM (JR405E)
Check Trans Lamp Operation
The check trans lamp is located in the instrument panel
cluster. The check trans lamp indicates that a transmission
related fault has occurred and vehicle service is
required. The following is a list of the modes of
operation for the check trans lamp:
• The check trans lamp illuminates for approximately 3 seconds when the ignition switch is turned ON,
with the engine OFF. This is a bulb test to the
check trans lamp is able to illuminate.
• The check trans lamp turns OFF after the engine is started if a diagnostic fault is not present.
• The check trans lamp remains blink after the engine is started if the TCM detects a fault. A DTC
is stored any time the TCM blinks the check trans
lamp due to a transmission related fault has
occurred.
Line Pressure Control
Solenoid valve outputs Pressure control (PC) solenoid valve
Switch inputsTransmission range (TR) switch
Sensor inputs
Input shaft speed (ISS) sensor
Output shaft speed (OSS) sensor
Accelerator pedal position signal (via ECM)
Engine speed signal (via ECM)TCM

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

7A2-156 TRANSMISSION CONTROL SYSTEM (JR405E)
Gearshift Control & Shift Map Selection
The TCM commands each shift solenoid valve based
on the traveling mode switch (power drive/ 3rd start),
transmission range switch, the vehicle speed, the
accelerator pedal angle and other input signals, to
control the optimum gear position automatically. Shift
features have been set up to the TCM as shift map; 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 transmission fluid temperature, hill climbing, and
downward travel have been set up to the TCM. These
are automatically switched depending on the driving
conditions. When the transmission fluid temperature is
lower than 10 °C (50 °F), gearshift from the 3rd to the
4th is inhibited.
Shift Map
The TCM selects either of the following shift map
depending on the driving conditions. High Temperature Mode
Condition for setting the high temperature mode shift
map;
• Transmission fluid temperature is more than 122 °C
(252 °F) for 10 seconds.
Condition for canceling the high temperature mode shift
map;
• Transmission fluid temperature is less than 115 °C
(239 °F) for 10 seconds
Notice: High temperature mode may be set with
driving conditions other than the setting condition met
in order to protect from a thermal damage.
3rd Start Mode
Condition for setting the 3rd start mode shift map;
All of the following conditions are met:
• 3rd start switch is pressed
• Vehicle speed is less than 11 km/h (7 MPH)
• Transmission fluid is less than 115 °C (239 °F)
• Accelerator pedal position is less than 8%
• Selector lever is D range
Condition for canceling the 3rd start mode shift map;
Either of the following condition is met:
• 3rd start switch is pressed again
• Vehicle speed is more than 34 km/h (21 MPH)
• Selector lever is other than D range
4L Mode
Condition for setting the 4L mode shift map;
All of the following conditions are met:
• 4L switch is On
• Vehicle speed is more than 5 km/h (3 MPH)
Condition for canceling the 4L mode shift map;
Either of the following condition is met:
• 4L switch is On
• Vehicle speed is more than 5 km/h (3 MPH)
TCM
Sensor inputs
Input shaft speed (ISS) sensor
Output shaft speed (OSS) sensor
Transmission fluid temperature (TFT) sensor
Accelerator pedal position signal (via ECM)
Engine speed signal (via ECM)
Switch inputs
Transmission range (TR) switch
Power drive switch
3rd start switch
Brake pedal switch
4WD low gear signal (via TCCM)
Solenoid valve outputs
Low & reverse brake solenoid valve
2-4 brake solenoid valve
High clutch solenoid valve
Low clutch solenoid valve
Lamp control outputs
Power drive lamp
3rd start lamp
OFF
ON
OFF ON OFF
OFF
Low
Priority Shift map 3rd start
lamp Power drive
lamp
High temperature mode
3rd start mode
4L mode
Down slope mode when
power drive SW Off
Down slope mode when
power drive SW On
Power drive mode
Up slope mode
Normal mode
High

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-157
Down Slope Mode
Condition for setting the down slope mode shift map;
All of the following conditions are met:
• Brake pedal switch is depressed
• Accelerator pedal is released
• Vehicle speed is more than 60 km/h (36 MPH)
• Increment of vehicle speed is more than 1 km/h (1 MPH) per second
• Selector lever is D or 3 range
Condition for canceling the down slope mode shift map;
Either of the following condition is met:
• Accelerator pedal is depressed
• Selector lever is other than D or 3 range Power Drive Mode
When the power drive switch is ON, the TCM switches
shift map to the power drive mode map and performs
gearshift control from 1st to 4th to gain more
acceleration compared with normal mode.
Up Slope Mode
Up slope reasoning value is calculated from the
averaged accelerator pedal angle and the averaged
acceleration. Otherwise, up slope reasoning value is
calculated from the vehicle speed. The TCM selects a
up slope mode when the former is bigger than the
latter.
Lock Up Control
Legend 1. TCC solenoid valve
2. Solenoid fluid pressure
3. Lock up control spool valve
4. Torque converter clutch (TCC) 5. Torque converter front cover
6. TCC engagement fluid pressure
7. TCC disengagement fluid pressure
TCM
Sensor inputs
Input shaft speed (ISS) sensor
Output shaft speed (OSS) sensor
Transmission fluid temperature (TFT) sensor
Accelerator pedal position signal (via ECM)
Engine speed signal (via ECM)
Solenoid valve outputsTorque converter clutch (TCC) solenoid valve

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007

7A2-158 TRANSMISSION CONTROL SYSTEM (JR405E)
The TCM controls the torque converter clutch (TCC)
solenoid valve based on the accelerator pedal angle,
input shaft speed, output shaft speed and transmission
fluid temperature.
Smooth lock up control is employed to engage or
disengage the TCC smoothly at the time of lock up On
or Off. When the TCM determines the TCC
engagement, the solenoid valve control duty cycle
(pulse width modulation [PWM]) signal is gradually
increased (5% to 95%) and the transmission fluid
between the TCC piston and torque converter front
cover is gradually drained. As a result, the TCC piston
is fitted slowly to the torque converter front cover under
fluid pressure securing smooth lock up engagement. The lock up control does not start when the
transmission fluid temperature is less than 20 °C (68 °F)
even though the vehicle is at the lock up control speed
area. The lock up control disengages when the
accelerator pedal angle is released.
Direct Electronic Shift Control (DECS)
Legend 1. Oil pump
2. Pressure regulator spool valve
3. ON/ OFF type solenoid valve (pressure control [PC]
solenoid valve 4. Duty cycle type solenoid valve (shift solenoid valve)
5. Amplifier (AMP) valve
6. Clutch
Solenoid valve outputs
Pressure control (PC) solenoid valve
Low & reverse brake solenoid valve
2-4 brake solenoid valve
High clutch solenoid valve
Low clutch solenoid valve
TCM
Sensor inputsInput shaft speed (ISS) sensor
Output shaft speed (OSS) sensor
Transmission fluid temperature (TFT) sensor
Accelerator pedal position signal (via ECM)
Engine speed signal (via ECM)
Switch inputs
Low & reverse brake transmission fluid
pressure (TFP) switch
2-4 brake transmission fluid pressure (TFP)
switch
High clutch transmission fluid pressure (TFP)
switch

BACK TO CHAPTER INDEX
TO MODEL INDEX
ISUZU KB P190 2007