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.
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ISUZU KB P190 2007
CONSTRUCTION AND FUNCTION 7A1-33
LEARNING FUNCTION
• Oil pressure control timing is optimally corrected at the time of clutch engagement and disengagement. It
is controlled to bring the shift time to the value preset to the TCM, and compensate for the changes in
engine performance and transmission characteristics.
• When the gear is shifted, the clutch pressure 2 is optimally corrected so that the shift time 1 is as close
to the target value preset to the TCM. The variation in the engine performance and changes to
transmission characteristics which occur with time, can be compensated for based on the past shift
results.
• When the clutch is operated to shift the gear, the time of the clutch oil pressure release 4 on the
disengagement side is optimally corrected so that the change of the engine rpm
3 is optimum.
Note:
• When the battery terminal is disconnected, the contents of learning are cleared and as a result the shift
shock may increase. After the vehicle has traveled, learning is repeated and the shock decreases
gradually.
Figure 53. Learning Control
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7A1-34 CONSTRUCTION AND FUNCTION
MAJOR INPUT/OUTPUT COMPONENT AND THEIR FUNCTIONS
Speed sensor Detects output shaft revolution and sends rpm signal to TCM.
Turbine sensor Detects input shaft revolution and sends rpm signal to TCM.
Engine speed sensor Inputs engine revolution from engine control computer.
Brake switch Detects brake pedal operation by the driver and sends signal
to TCM.
Inhibitor switch Detects select lever position and sends signal to TCM.
Mode select switch Detects "Power Drive" or "3rd Start" selected by the driver and
sends signal to TCM.
4L switch (4W D Only) Inputs 4L mode from transfer control computer.
ATF thermo sensor Detects ATF temperature and sends signal to TCM.
High clutch oil pressure switch Detects high clutch supply oil pressure and sends signal to
TCM.
2-4 brake oil pressure switch Detects 2-4 brake supply oil pressure and sends signal to
TCM.
Low & Reverse brake oil pressure switch Detects low & reverse brake supply oil pressure and sends signal to TCM.
Accelerator Pedal position sensor Inputs throttle opening angle from engine control computer.
Input
TCM Judges necessary line pressure, gear shifting point and lock-up
operation based on electrical signals from switches and
sensors and sends appropriate signals to solenoids.
Line pressure solenoid Regulates oil pump delivery pressure to the appropriate line
pressure for current driving conditions based on a signal from
TCM.
Low clutch solenoid Selects appropriate gear shifting position for current driving
conditions and regulates low clutch supply oil pressure based
on a signal from TCM.
High clutch solenoid Selects appropriate gear shifting position for current driving
conditions and regulates high clutch supply oil pressure based
on a signal from TCM.
2-4 brake solenoid Selects appropriate gear shifting position for current driving
conditions and regulates 2-4 brake supply oil pressure based
on a signal from TCM.
Low & Reverse brake solenoid Selects appropriate gear shifting position for current driving
conditions and regulates low & reverse brake supply oil
pressure based on a signal from TCM.
Lock-up solenoid Regulates lock-up pressure to appropriate level for current
driving conditions based on a signal from TCM.
Mode indicator lamp Indicates POW ER DRIVE or 3rd START switch position.
Speed meter signal (2W D Only) Outputs vehicle speed to the speed meter.
A/T OIL TEMP indicator lamp Indicates A/T OIL TEMP indicator lamp in case of high
temperature.
Output
CHECK TRANS indicator lamp Indicates CHECK TRANS indicator lamp in case of
malfunction.
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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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TRANSMISSION CONTROL SYSTEM (JR405E) 7A2-17
Transmission Control Module (TCM)
Connector End Views
TCM (Gray connector)
TCM (White connector)
Connector No.C-94
Connector color Gray
Test adapter No. J-35616-64A
Pin No. Wire color Pin function
1 RED/ WHT Battery voltage
2 YEL/ VIO P range switch signal
3 RED Brake pedal switch signal
4 PNK/ WHT 3rd start lamp control
5 VIO/ GRN Keyword serial data communication
6 — Not used
7 BLK/ RED Engine speed signal input
8 — Not used
9 — Not used
10 BLK/ YEL Vehicle speed signal output (2WD)
11 GRN/ WHT 3rd start switch signal
12 BLU/ WHT 4WD low signal output
13 — Not used
14 — Not used
15 — Not used
16 RED/ WHT Accelerator pedal position (APP) signal input
17 BLK/GRN 3 range switch signal
18 YEL/ BLK Diagnostic request switch
19 ORN/ BLU Transmission oil temperature lamp control
20 GRY/ YEL Check trans lamp control
1
10
19
2
11
20
3
12
21
4
13
5
14
6
15
7
16
22
8
17
23
9
18
24
21 PNK Power lamp control
22 — Not used
23 — Not used
24 GRN/ YEL Power drive switch signal
Connector No. C-95
Connector color White
Test adapter No. J-35616-64A
Pin No. Wire color Pin function
1 RED/ YEL 2-4 brake TFP switch signal
2 PNK/ BLK 2 range switch signal
3 BRN/ RED ISS sensor signal
4 BLU TFT sensor signal
5 BLK Ground
6 BLU/ BLK Low & reverse brake solenoid control
7 BLK/ YEL 2 & 4 brake solenoid control
8 RED High clutch solenoid control
9 WHT/ BLU Low clutch solenoid control
10 RED/ BLK N range switch signal 11 BLU D range switch signal
12 YEL Low & reverse brake TFP switch
13 YEL/ RED OSS sensor signal
14 BLU/ BLK TFT sensor low reference
15 — Not used
16 — Not used
17 BLK TCC solenoid control
18 WHT Ignition voltage
1
10
19
2
11
20
3
12
21
4
13
5
14
6
15
7
16
22
8
17
23
9
18
24
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7A2-24 TRANSMISSION CONTROL SYSTEM (JR405E)
Scan Tool Data List
The Transmission Scan Tool Data List contains all
transmission related parameters that are available on
the scan tool. Use the Transmission Scan Tool Data
List only after the following is determined:
• The Transmission Controls - Diagnostic System Check is completed. • On-board diagnostics are functioning properly.
Scan tool values from a properly running engine may
be used for comparison with the transmission you are
diagnosing. The Transmission Scan Tool Data List
represents values that would be seen on a normal
running engine. Only the parameters listed below are
referenced in this service manual for use in diagnosis.
Scan Tool Parameter Units DisplayedTypical Data
Operating Conditions: Engine idle/ Engine coolant temperature is between 75 to 85 °C (167 to 185 °F)/ Accelerator pedal is not
pressed/ Park range/ Transfer case is 2H position/ Accessories OFF
Accelerator Pedal Position %0%
Engine Speed RPMNearly 700 RPM
AT Input Speed (Automatic Transmission) RPM600 to 700 RPM
TCC Slip Speed (Torque Converter Clutch) RPMLess than 100 RPM
AT Output Speed (Automatic Transmission) RPM0 RPM
Vehicle Speed km/h/ MPH0 km/h / MPH
Current Gear 1st/ 2nd/ 2nd L-Up/ 3rd/ 3rd
L-Up/ 4th/ 4th L-Up 1st
Estimated Gear Ratio : 132.77:1
Transmission Range (TR) Park/ Neutral/ Reverse/
Drive/ Drive 3/ Drive 2/ Drive 1 Park
TR Switch P (Transmission Range) On/ OffOn
TR Switch R (Transmission Range) On/ OffOff
TR Switch N (Transmission Range) On/ OffOff
TR Switch D (Transmission Range) On/ OffOff
TR Switch 3 (Transmission Range) On/ OffOff
TR Switch 2 (Transmission Range) On/ OffOff
TR Switch L (Transmission Range) On/ OffOff
PCS Command (Pressure Control Solenoid) On/ OffOn
Low & Reverse Brake Solenoid Command %100%
Low & Reverse Brake Pressure Switch On/ OffOff
2-4 Brake Solenoid Command %100%
2-4 Brake Pressure Switch On/ OffOff
High Clutch Solenoid Command %100%
High Clutch Pressure Switch On/ OffOff
Low Clutch Solenoid Command %0%
TCC Solenoid (Torque Converter Clutch) %5%
Transmission Fluid Temperature °C/ °F V arie s
Transmission Oil Temperature Lamp On/ OffOff
TCM Status Temp. (Temperature Transmission Control Module) Low/ HighLow
4 Wheel Drive Low On/ OffOff
TCM Status Transfer (Transmission Control Module) Low/ HighHigh
TCM Status Down Slope (Transmission Control Module) On/ OffOff
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ISUZU KB P190 2007
7A2-40 TRANSMISSION CONTROL SYSTEM (JR405E)
DTC P0710 (Flash Code 15)
Circuit Description
The transmission fluid temperature (TFT) sensor is
attached to the lower part of the valve body assembly.
The TFT sensor is a variable resistor and it measures
the temperature of the transmission fluid. The sensor
has a signal circuit and a low reference circuit. The
TCM supplies 2.5 volts to the signal circuit and a
ground for the low reference circuit. 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 TCM detects an
excessively low or high signal voltage, this DTC will set.
Condition for Running the DTC • The ignition switch is ON.
Condition for Setting the DTC
Either of following condition is met: • The TCM detects that the TFT sensor signal voltage is less than 0.1 volts (more than 146 °C
[295 °F]) when the selector lever is P or N range for
longer than 5 minutes.
• The TCM detects that the TFT sensor signal voltage is more than 2.43 volts (less than -40 °C [-
40 °F]) for 10 seconds when the vehicle speed is
more than 20 km/h (12 MPH).
Action Taken When the DTC Sets • The TCM does not blink the Check Trans lamp. • The TCM inhibits 4th gear. (If the engine speed is
more than 470 PRM for 10 minutes, shifting to 4th
gear is allowed.)
• The TCM inhibits lock up control. (If the engine speed is more than 470 RPM for 10 minutes, lock
up control is allowed.)
• The TCM uses a TFT substitution of 80 °C (176 °F)
for transmission control.
Condition for Clearing the DTC • current DTC clears when the diagnostic runs and does not fail.
Diagnostic Aids • If an intermittent condition is suspected, refer to Intermittent Conditions in this section.
• Use the Temperature vs. Resistance table to test the TFT sensor at various temperature levels to
evaluate the possibility of a skewed sensor. A
skewed sensor could result in poor driveability
(poor shift quality) concerns.
Test Description
The numbers below refer to the step number on the
Circuit/ System Testing.
5. If the TFT sensor signal circuit is shorted to ground,
A/T Oil Temp lamp turns ON and the TCM switches
shift map to the high temperature mode until this DTC
is set.
Schematic Reference: Transmission Controls
Schematics
Connector End View Reference: Transmission
Controls Connector End Views or TCM Connector End
Views
Circuit/ System Testing DTC P0710
Step Action Value(s)Yes No
1 Did you perform the Diagnostic System Check -
Transmission Controls? —
Go to Step 2 Go to Diagnostic
System Check -
Transmission Controls
2 1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Observe the Transmission Fluid Temperature (TFT) parameter with a scan tool within 5
minutes from the ignition switch is ON.
Is the TFT parameter more than the specified
value? 146
°C (295 °F)
Go to Step 4 Go to Step 3
3 Is the TFT parameter less than the specified value
at Step 2? -40
°C (-40 °F)
Go to Step 7 Go to Diagnostic
Aids
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ISUZU KB P190 2007
7A2-54 TRANSMISSION CONTROL SYSTEM (JR405E)
91. Remove the transmission oil pan. Refer to
repair instruction (On-Vehicle Service).
2. Inspect the oil pan and the fluid for contamination.
Was excessive contamination found? —
Replace the
transmission fluid
and filter and Go to Step 10 Go to Step 11
10 Drive the vehicle while observing the DTC
Information with a scan tool.
Does the DTC fail this ignition? —
Go to Step 11 Go to Step 13
11 1. Remove the all shift solenoid valve and all
TFP switch from the valve body assembly and
perform function check. Refer to repair
instructions (On-Vehicle Service).
2. Repair or replace as necessary.
Did you find and correct the condition? —
Go to Step 13 Go to Step 12
12 Repair or replace the valve body assembly/
clutches or brakes (On-Vehicle Service or Unit
Repair).
Did you complete the repair or replacement? —
Go to Step 13 —
13 1. Reconnect all previously disconnected
components or harness connector(s).
2. Clear the DTCs with a scan tool.
3. Turn OFF the ignition for 30 seconds.
4. Start the engine.
5. Drive the vehicle while observing the DTC Information with a scan tool.
Did the DTC fail this ignition? —
Go to Step 2 Go to Step 14
14 Observe the DTC Information with a scan tool.
Are there any DTCs that you have not diagnosed? —
Go to DTC List System OK
Step
Action Value(s)Yes No
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