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
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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
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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
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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
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ISUZU KB P190 2007
TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-167
Second Gear
Legend1. Input shaft
2. Front planetary carrier
3. Front pinion gear
4. Front sun gear
5. Rear sun gear
6. Rear pinion gear
7. Rear internal gear
8. Output shaft
9. Reverse clutch 10. 2-4 brake
11. High clutch
12. Front internal gear
13. Rear planetary carrier
14. Low clutch
15. Low & reverse brake
16. Low one-way clutch
17. Parking pawl
The driving force from the input shaft (1) is transmitted
to the rear sun gear (5) and reverse & high clutch drum.
As in the case of the 1st gear, the low clutch (14) is
engaged and the movement of the rear internal gear (7)
is restricted. Since the 2-4 brake is engaged (10), the
front sun gear (4) is fixed. As a result, movement of the
rear internal gear (7) is restricted, and the driving force
transmitted to the rear sun gear (5) rotates the rear
planetary carrier (13) clockwise. The rotating speed of
the rear planetary carrier (13) is higher than in 1st gear as the rear internal gear (7) rotates. When decelerating,
the engine brake is applied.
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ISUZU KB P190 2007
7A2-168 TRANSMISSION CONTROL SYSTEM (JR405E)
Third Gear
Legend1. Input shaft
2. Front planetary carrier
3. Front pinion gear
4. Front sun gear
5. Rear sun gear
6. Rear pinion gear
7. Rear internal gear
8. Output shaft
9. Reverse clutch 10. 2-4 brake
11 . H i g h c l u t c h
12. Front internal gear
13. Rear planetary carrier
14. Low clutch
15. Low & reverse brake
16. Low one-way clutch
17. Parking pawl
The driving force from the input shaft (1) is transmitted
to the rear sun gear (5) and reverse & high clutch drum.
As in the case of the 1st gear and 2nd gear, the low
clutch (14) is engaged and the movement of the rear
internal gear (7) is restricted. Since the high clutch (11)
is engaged, the driving force from the input shaft (1) is
directly transmitted to the rear internal gear (7). As a
result, the speed of the rear sun gear (5) and the rear
internal gear (7) becomes the same as that of the input
shaft (1), so that the rear pinion gear rotates (6) not independently but together with the rear sun gear (5)
and rear internal gear (7). When decelerating, the
engine brake is applied.
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ISUZU KB P190 2007
7A3-2 ON-VEHICLE SERVICE (JR405E)
DESCRIPTION
Before performing on-vehicle service on the automatic
transmission, check that the engine idling speed and
general engine condition are normal.
For shift interlock function, if the ignition key is out of
“LOCK” position, the shift lever select button can not be
pushed. (shift lever can not be operated.)
RTW 77ASH000901
AUTOMATIC TRANSMISSION FLUID (ATF)
Inspect
Remove the transmission dipstick to check the condition
of the ATF.
Check the color and smell of the ATF.
If the ATF is abnormal color or smells burnt, replace it
and investigate the cause of trouble.
Coloor of ATF Condition Clear red Normality
Blackish discoloration Defects of power train
parts (clutches)
W hite turbidity Include water
Discoloration of red brown Deterioration of ATF
ATF LEVEL
Inspect
Hot Level
1. W arm up the engine and the transmission by driving
the vehicle on the road so that the temperature
reaches around 80 °C (176 °F).
Do not turn the engine off.
2. Park the vehicle on a level surface.
3. Apply the parking brake firmly.
4. Let the engine run at idle.
Move the select lever slowly through all the gea
r
positions.
Stop in each gear position just long enough for the transmission to engage.
5. Return the select lever to either “P” or “N”.
6. Remove the ATF level dipstick.
7. W ipe the dipstick clean with a paper towel.
8. Reinsert the dipstick and wait several seconds.
9. Remove the dipstick.
The ATF level should be inside the “H” range on the dipstick.
242R300001
If the ATF level is below the “H” range, ATF must be added.
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ISUZU KB P190 2007
ON-VEHICLE SERVICE (JR405E) 7A3-3
Cold Level
The vehicle must not have been driven so that the
temperature reaches around 20 °C (68 °F) before the
cold level check is made.
1. Park the vehicle on a level surface.
2. Apply the parking brake firmly.
3. Start the engine and allow it to warm up.
The engine coolant temperature gauge needle should be midway between the “C” mark and “H”
mark.
4. Let the engine run at idle.
Move the select lever slowly through all the gea
r
ranges.
Stop in each range just long enough for the transmission to engage.
5. Return the select lever either “P” or “N”.
6. Remove the ATF level dipstick.
7. W ipe the dipstick clean with a paper towel.
8. Reinsert the dipstick and wait several seconds.
9. Remove the dipstick.
The ATF level should be inside the “C” range on the dipstick.
If the ATF level is below the “C” range, ATF must be added.
242R300002
ATF CHANGE
1. Park the vehicle on level ground and block the rear
wheels.
2. Start the engine and allow it to idle until the ATF reaches a temperature of 40-50 °C (104-122 °F).
3. Stop the engine.
4. Raise the front to the vehicle and support with suitable safety stands.
5. Remove the drain plug from the oil pan and drain the ATF (approximately 6 liters).
6. Remove the oil pan.
7. Inspect the oil pan (details written below).
8. Install the oil pan.
Note:
Use a new gasket. Clean the oil pan and magnet.
Oil pan bolt torque : 8 N ⋅m (0.8 kgf ⋅m/69 lb ⋅in)
9. Replace the gasket and install the drain plug.
Drain plug torque : 35 N ⋅m (3.6 kgf ⋅m/26 lb ⋅ft)
Note:
Do not reuse the old washer (gasket).
Clean the drain plug (especially the threaded section).
10.Remove the safety stands and wheel blocks.
11.Pour about 5 liters of new ATF.
12. Start the engine. W ith your foot on the brake, move the shift lever through each gear range, and shift to
“P” range.
13.Check the ATF level. Add more ATF carefully as necessary using the dipstick. Refer to “ATF LEVEL”
preciously in this section.
Note:
Keep the engine idle (do not stop it) during the ATF level
adjustment.
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ISUZU KB P190 2007