7A2-134 TRANSMISSION CONTROL SYSTEM (JR405E)
TCM Signal Test
Inspection Tool
Use a DMM to measure voltage and circuit continuity.
Also use an oscilloscope to measure waveform. Refer
to the following table for the specified ranges or
reference waveform. Since the TCM terminals are extremely small, use
appropriate test adapter from the test adapter kit. This
will make measurement easier.
Pin No. Wire color Pin function DMM (+) DMM (-) Test condition Standard value
1 of C-94 RED/ WHT Battery voltage 1 of C-94 Ground Any time Nearly 12 volts
2 of C-94 YEL/ VIO P range switch signal 2 of C-94 Ground P range
Nearly 12 volts
Other than P range Less than 2 volts
3 of C-94 RED Brake pedal switch
signal 3 of C-94 Ground Pedal is released Less than 2 volts
Pedal is applied Nearly 12 volts
4 of C-94 PNK/ WHT 3rd start lamp control 4 of C-94
(back probe) Ground Lamp OFF Nearly 12 volts
Lamp ON Less than 2 volts
5 of C-94 VIO/ GRN Keyword serial data
communication 5 of C-94 7 of B-58 Ignition OFF
Continuity
6 of C-94 — Not used— — ——
7 of C-94 BLK/ RED Engine speed signal
input 7 of C-94
(back probe) 5 of C-95
(back
probe) Engine run at 2000
RPM Nearly 6.2 volts by
AC range or
waveform
8 of C-94 — Not used— — ——
9 of C-94 — Not used— — ——
10 of C-94 BLK/ YEL Vehicle speed signal
output (2WD) 10 of C-94
(back probe) 5 of C-95
(back
probe) Vehicle run at 20 km/h
(12 MPH) Nearly 6.5 volts by
AC range or waveform
11 of C-94 GRN/ WHT 3rd start switch signal 11 of C-94
(back probe) GroundSwitch is released Nearly 12 volts
Switch is pressed Less than 2 volts
12 of C-94 BLU/ WHT 4WD low signal output 12 of C-94
(back probe) Ground 4L mode Less than 2 volts
Other than 4L Nearly 12 volts
13 of C-94 — Not used— — ——
14 of C-94 — Not used— — ——
15 of C-94 — Not used— — ——
16 of C-94 RED/ WHT Accelerator pedal
position (APP) signal
input 16 of C-94
(back probe) 5 of C-95Pedal is released (0%) Off duty ratio 10%
Pedal is fully applied (100%) Off duty ratio 90%
17 of C-94 BLK/GRN 3 range switch signal 17 of C-94 Ground 3 range
Nearly 12 volts
Other than 3 range Less than 2 volts
18 of C-94 YEL/ BLK Diagnostic request
switch 5 of C-9411 o f B -
58 Ignition OFF
Continuity
19 of C-94 ORN/ BLU Transmission oil
temperature lamp control 19 of C-94
(back probe) Ground Lamp OFF Nearly 12 volts
Lamp ON Less than 2 volts
20 of C-94 GRY/ YEL Check trans lamp
control 20 of C-94
(back probe) Ground Lamp OFF Nearly 12 volts
Lamp ON Less than 2 volts
21 of C-94 PNK Power drive lamp
control 21 of C-94
(back probe) Ground Lamp OFF Nearly 12 volts
Lamp ON Less than 2 volts
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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
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ISUZU KB P190 2007
7D1-6 TRANSFER CONTROL SYSTEM
the 4×2 - 4 ×4 shift rod. W hen moving in 4 ×2 direction, a spring
standby mechanism is provided between the rod and sleeve so
that the rod is positioned at the 4 ×2 position, while the sleeve is
at the 4 ×4 position.
This mechanism is provided to protect the shift mechanism
from the force and to prevent movement of the sleeve
(torsional torque etc. of the drive system). By releasing the
preventive force, the sleeve can move to the 4 ×2 state by the
spring force.
Neutral switch
The neutral switch detects the movement of the shift rod
driving the high-low sleeve.
PUSH close is achieved with the PUSH close switch when the
shift rod is positioned between the High and the Low, at the
neutral state.
High-Low Sleeve & Arm
The spring standby mechanism is provided for the high-low
sleeve in both directions of the high-low shift rod. Therefore,
the rod position and the actual sleeve position may be offset in
some cases.
This system is provided to protect the shift mechanism from a
collision due to coincidence of the high and low phases of the
engaged splines. By giving rotational force to the preventing
phase coincidence, the splines are moved to the proper
engagement position by the spring force.
Shift actuator
The output shaft is rotated by the built-in motor and the transfer
position is switched.
Detection (limit) switches to detect the rotating angle of the
output shaft that is provided to the actuator at 4 positions.
These are connected to the transfer controller through the
vehicle harness to constantly transmit the actuator operating
angle and changes in its transfer status.
7B4-PDF2
4WD indicator (in meter panel)
This lamp indicates the following items:
Valve check
Drive condition (2W D-4W D)
Operating condition (2Hz: Actuator in operation, mechanism
standby)
Restrictions on operation (4Hz, including indication of
interrupted operation due
to excessive load)
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TRANSFER CONTROL SYSTEM 7D1-7
7B4-PDF3
4L indicator (in meter panel)
This lamp indicates following items:
Valve check
Driving status (High-Low)
Operating status (2Hz: Actuator in operation, mechanism
standby)
Restrictions on operation (4Hz)
RTW 77DSH000601
Neutral indicator (in operation switch panel)
This LED indicates following items:
LED check
Driving status (Neutral)
Operating status (2Hz: Actuator in operation, mechanism
standby)
Restrictions on operation (4Hz)
7B4-PDF5
Check 4WD warning light (in meter panel)
This light indicates following items:
Valve check
Faulty actuator limit SW , and circuit related faults with the limit
switch
RTW 77DSH000501
4WD switch
Switch to transmit a switching command to the 2H, 4H,
Neutral, or 4L position.
It comprises 3 PUSH momentary switches. By pushing the 2H
and 4L switches for 10 seconds,
operation is changed to the neutral position.
To shift from the neutral to another position, push another
switch for 10 seconds.
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ISUZU KB P190 2007
7D1-12 TRANSFER CONTROL SYSTEM
Functions of Switch and indicator Lamp
Transfer-related indicator lamp and switch function
Item 4WD
lamp 4L lamp Neutral
lamp Check
4WD
warning light 4WD
switch Actu ato r
detection (limit)
switches
LS1, LS2, LS3. and LS4
1 = on
2 = off Transfer
4WD
switch Transfer
neutral switch SOF
actuator switch Or
Axl e
dummy Remarks
2H Off Off Off Off No
operation 1,0,1,0 Open Open Open -----
4H start
of
operation Off Off Off Off 4H position
for 0.1
second 1,0,1,0 Open Open Open Switch
operation sensor
Start of
operation Blinking
(2HZ) Off Off Off No
operation 1,1,1,0
0,0,1,0
0,1,1,0
0,1,1,1 Open Open Open
2H to 4H
while
driving
During
operation
(Synchro) Blinking
(2HZ) Off Off Off No
operation 1,1,1,0
0,0,1,0
0,1,1,0
0,1,1,1 Open Open Open 2H to 4H
using
synchro and
retrial
During
operation (Axle
drive) Blinking
(2HZ) Off Off Off No
operation 0,0,1,1 Closed Open Open Axle drive
Axle
waiting Blinking
(2HZ) Off Off Off No
operation 0,0,1,1 Closed Open Open Axle drive
4H On Off Off Off No
operation 0,0,1,1 Closed Open Closed -----
4L start
of
operation On Off Off Off 4L position
for 0.1
second 0,0,1,1 Closed Open Closed Switch
operation sensor
Start of
operation On Blinking
(2HZ) Off Off No
operation 0,0,0,1
0,1,0,1 Closed Open Closed 4H to 4L
while
driving
During
operation (N) Off
Blinking
(2HZ) Off Off No
operation 0,0,0,1
0,1,0,1 Closed Closed Closed 4H to 4L
through neutral
During
operation (N) Off
Blinking
(2HZ) Off Off No
operation 0,1,0,0 Closed Closed Closed 4H to 4L
through neutral
During
operation (N) Off
Blinking
(2HZ) Off Off No
operation 1,1,0,0 Closed Closed Closed 4H to 4L
through neutral
4L
waiting On Blinking
(2HZ) Off Off No
operation 1,1,0,1 Closed Closed Closed 4H to 4L
while
waiting
4L On On Off Off No
operation 1,1,0,1 Closed Open Closed -----
4H start of
operation On Off Off Off 4H position
for 0.1
second 1,1,0,1 Closed Open Closed Switch
operation sensor
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ISUZU KB P190 2007
TRANSFER CONTROL SYSTEM 7D1-13
Item 4WD
lamp 4L lamp Neutral
lamp Check
4WD
warning light 4WD
switch Actu ato r
detection (limit)
switches
LS1, LS2, LS3. and LS4
1 = on
2 = off Transfer
4WD
switch Transfer
neutral switch SOF
actuator switch Or
Axl e
dummy Remarks
During
operation On Blinking
(2HZ) Off Off No
operation 1,1,0,1 Closed Open Closed 4L to 4H
while
driving
During
operation (N) Off
Blinking
(2HZ) Off Off No
operation 1,1,0,0 Closed Closed Closed 4L to 4H
through neutral
During
operation Off Blinking
(2HZ) Off Off No
operation 0,1,0,1
0,0,0,1 Closed Closed Closed 4L to 4H
while
driving
4H
waiting Off Blinking
(2HZ) Off Off No
operation 0,0,1,1 Closed Closed Closed
4L to 4H
while
waiting
4H On Off Off Off No
operation 0,0,1,1 Closed Open Closed -----
2H start of
operation On Off Off Off 2H position
for 0.1
second 0,0,1,1 Closed Open Closed Switch
operation sensor
Start of
operation Blinking
(2HZ) Off Off Off No
operation 0,1,1,1
0,1,1,0
0,0,1,0
1,1,1,0 Closed Open Closed
2H to 4H
while
driving
During
operation (Axle) Blinking
(2HZ) Off Off Off No
operation 0,1,1,1
0,1,1,0
0,0,1,0
1,1,1,0 Open Open Closed Axle drive
Axle
waiting
Blinking
(2HZ) Off Off Off No
operation 1,0,1,0 Open Open Closed Axle
waiting
2H Off Off Off Off No
operation 1,0,1,0 Open Open Open -----
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ISUZU KB P190 2007
7D1-14 TRANSFER CONTROL SYSTEM
2H to 4H retrial
Item 4WD
lamp 4L lamp Neutral
lamp Check
4WD
warning light 4WD
switch Actu ato r
detection (limit)
switches
LS1, LS2, LS3. and LS4
1 = on
2 = off Transfer
4WD
switch Transfer
neutral switch SOF
actuator switch Or
Axl e
dummy Remarks
2H Off Off Off Off No
operation1,0,1,0 Open Open Open -----
4H start
of
operation Off Off Off Off 4H
position for 0.1
second 1,0,1,0 Open Open Open -----
Start of
operation Blinking
(2HZ) Off Off Off No
operation 1,1,1,0
0,0,1,0
0,1,1,0
0,1,1,1 Open Open Open
2H to 4H
while
driving
During
operation
(Synchro)
(Go to 4H if synchro
complete) Blinking
(2HZ) Off Off Off No
operation 1,1,1,0
0,0,1,0
0,1,1,0
0,1,1,1 Open Open Open 2H to 4H
using
synchro
and retrial X 2
Abandoned
operation (2H) Blinking
(4HZ) Off Off Off No
operation 1,0,1,0 Open Open Open Return to
2H
2H
indication
after
10second
s
Off Off Off Off No
operation1,0,1,0 Open Open Open -----
• Completion of transfer case H-L area and axle shift timing may cause some variation in the 2Hz blinking pattern.
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ISUZU KB P190 2007
7D1-16 TRANSFER CONTROL SYSTEM
Transfer-related indicator lamp and switch function
Skip operation
Item 4WD
lamp 4L lamp Neutral
lamp Check
4WD
warning light 4WD
switch Actu ato r
detection (limit)
switches LS1,
LS2,
LS3. and LS4
1 = on
2 = off Transfer
4WD
switch Transfer
neutral switch SOF
actuator switch Or
Axl e
dummy Remarks
2H Off Off Off Off No
operation1,0,1,0 Open Open Open -----
4L start of
operation Off Off Off Off 4L
position for 0.1
second 1,0,1,0 Open Open Open
Switch
operation sensor
Start of
operation Blinking
(2HZ) Blinking
(2HZ) Off Off No
operation 1,1,1,0
0,0,1,0
0,1,1,0
0,1,1,1 Open Open Open
2H to 4H
while
driving
During
operation
(Synchro) Blinking
(2HZ) Blinking
(2HZ) Off Off No
operation 1,1,1,0
0,0,1,0
0,1,1,0
0,1,1,1 Open Open Open 2H to 4H
using
synchro
and retrial
During
operation (Passing through 4H) Off
Blinking
(2HZ) Off Off No
operation 0,0,1,1 Closed Open Open -----
During
operation (Passing through 4H) Off
Blinking
(2HZ) Off Off No
operation 0,0,1,1
0,1,0,1 Closed Open Open -----
During
operation
(N)
On Blinking
(2HZ) Off Off No
operation
0,0,1,1
0,1,0,1 Closed Open Closed -----
During
operation (N) On
Blinking
(2HZ) Off Off No
operation 0,1,0,0 Closed Open Closed Switch
operation sensor
During
operation (N) On
Blinking
(2HZ) Off Off No
operation 0,0,1,1 Closed Open Closed 4H to 4L
while
driving
During
operation (Axle
drive) Blinking
(2HZ) Blinking
(2HZ) Off Off No
operation 0,0,1,1 Closed Open Open
-----
Axle
waiting Blinking
(2HZ) Blinking
(2HZ) Off Off No
operation 0,0,1,1 Closed Open Open -----
4L waiting On Blinking
(2HZ) Off Off No
operation 1,1,0,1 Closed Closed Closed 4H to 4L
while
waiting
4L On On Off Off No
operation1,1,0,1 Closed Open Closed -----
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ISUZU KB P190 2007