2004 ISUZU TF SERIES service indicator

CRUISE CONTROL SYSTEM 8B-3
Service Precaution
WARNING: THIS VEHICLE HAS A SUPPLEMENTAL RESTRAIN SYSTEM (SRS). REFER TO THE SRS
COMPONENT AND WIRING LOCATION VIEW IN ORDER TO DETERMINE WHETHER YOU ARE
PERFORMING SERVICE ON OR NEAR THE SRS COMPONENTS OR THE SRS WIRING. WHEN YOU ARE
PERFORMING SERVICE ON OR NEAR THE SRS COMPONENTS OR THE SRS WIRING, REFER TO THE SRS
SERVICE INFORMATION. FAILURE TO FOLLOW WARNINGS COULD RESULT IN POSSIBLE AIR BAG
DEPLOYMENT, PERSONAL INJURY, OR OTHER WISE UNNEEDED SRS SYSTEM REPAIRS.

CAUTION: Always use the correct fastener in the proper location. When you replace a faster, use ONLY the
exact part number for that application. Dealer will call out those fasteners that require a replacement after
removal. Dealer will also call out the fasteners that require thread lockers or thread sealant. UNLESS
OTHERWISE SPECIFIED, do not use supplemental coatings (Paints, greases, or other corrosion inhibitors)
on threaded fasteners or fastener joint interfaces. Generally, such coatings adversely affect the fastener
torque and joint Clamping force, and may damaged the fastener. When you install fasteners, use the
correct tightening sequence and specifications. Following these instructions can help you avoid damage to
parts and systems.

General Description
The cruise control keeps the vehicle running at a fixed speed until a signal canceling this fixed speed is received.
When the main switch “AUTO CRUISE” is turned on with the vehicle in the running mode, the battery voltage is
applied to the control unit. When a signal from the control unit while the vehicle is in this state, the cruise control
actuator is activated to operate the system. Also, while the system is operating, the “AUTO CRUISE” indicator light
in the meter assembly lights up.





LTW48BSH000101
1. SET/COAST Switch Function
1. Set Function: When the SET/COAST switch is pressed and released with the main switch on, the speed at
which the vehicle is running at that moment is stored in the memory, and the vehicle automatically runs at the
stored speed.
2. COAST-down Function: When the SET/COAST switch is kept on while the vehicle in running, the vehicle
decelerates during that time. The speed at which vehicle is running when the control switch is pressed in the
memory, and the vehicle automatically returns to the stored speed.
3. Tap-down Function: When the SET/COAST switch is pressed and released instantaneously while the
vehicle is running, the vehicle decelerates a mile for each on/off operation. The vehicle speed at which the
vehicle was running when the SET/COAST was released last is stored in the memory, and the vehicle
automatically returns to this stored speed.

6E–226 4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0381 (Symptom Code 8) (Flash Code 67)
Glow Plug Indicator Circuit Voltage High
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?
—Go to Step 2Go to On Board
Diagnostic
(OBD) System
Check
2 1. Connect the Tech 2.
2. Review and record the failure information.
3. Select “F0: Read DTC Infor As Stored By ECU” in
“F0: Diagnostic Trouble Codes”.
Is the DTC P0381 (Symptom Code 8) stored as
“Present Failure”?—Go to Step 3Refer to
Diagnostic Aids
and Go to Step
3
3 1. Using the Tech 2, ignition “On” and engine “Off”.
2. Select “F1: Clear DTC Information” in “F0:
Diagnostic Trouble Codes” with the Tech 2 and
clear the DTC information.
3. Operate the vehicle and monitor the “F0: Read
DTC Infor As Stored By ECU” in the “F0:
Diagnostic Trouble Codes”.
Was the DTC P0381 (Symptom Code 8) stored in this
ignition cycle?—Go to Step 4Refer to
Diagnostic Aids
4 Is the ECM programmed with the latest software
release?
If not, download the latest software to the ECM using
the “SPS (Service Programming System)”.
Was the problem solved?—Verify repair Go to Step 5
5 Substitute a known good ECM and recheck.
Was the problem solved?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure. —Go to Step 6—
6 Replace the ECM.
Is the action complete?
IMPORTANT: The replacement ECM must be
programmed. Refer to section of the Service
Programming System (SPS) in this manual.
Following ECM programming, the immobilizer system
(if equipped) must be linked to the ECM. Refer to
section 11 “Immobilizer System-ECM replacement” for
the ECM/Immobilizer linking procedure.—Verify repair—

4JA1/4JH1 ENGINE DRIVEABILITY AND EMISSIONS 6E–361
SYMPTOM DIAGNOSIS
PRELIMINARY CHECKS
Before using this section, perform the “On-Board
Diagnostic (OBD) System Check” and verify all of the
following items:
The engine control module (ECM) and check engine
lamp (MIL=malfunction indicator lamp are operating
correctly.
There are no Diagnostic Trouble Code(s) stored.
Tech 2 data is within normal operating range. Refer to
Typical Scan Data Values.
Verify the customer complaint and locate the correct
symptom in the table of contents. Perform the
procedure included in the symptom chart.
VISUAL/PHYSICAL CHECK
Several of the symptom procedures call for a careful
visual/physical check. This can lead to correcting a
problem without further checks and can save valuable
time. This check should include the following items:
ECM grounds for cleanliness, tightness and proper
location.
Vacuum hoses for splits, kinks, and proper
connection. Check thoroughly for any type of leak or
restriction.
Air intake ducts for collapsed or damaged areas.
Air leaks at throttle body mounting area, mass air flow
(MAF) sensor and intake manifold sealing surfaces.
Wiring for proper connections, pinches and cuts.
INTERMITTENT
Important: An intermittent problem may or may not turn
on the check engine lamp (MIL=malfunction indicator
lamp) or store a Diagnostic Trouble Code. Do NOT use
the Diagnostic Trouble Code (DTC) charts for
intermittent problems.
The fault must be present to locate the problem.
Most intermittent problems are cased by faulty electrical
connections or wiring. Perform a careful visual/physical
check for the following conditions.
Poor mating of the connector halves or a terminal not
fully seated in the connector (backed out).
Improperly formed or damaged terminal.
All connector terminals in the problem circuit should
be carefully checked for proper contact tension.
Poor terminal-to-wire connection. This requires
removing the terminal form the connector body to
check.
Check engine lamp (MIL=malfunction indicator lamp)
wire to ECM shorted to ground.
Poor ECM grounds. Refer to the ECM wiring
diagrams.Road test the vehicle with a Digital Multimeter
connected to a suspected circuit. An abnormal voltage
when the malfunction occurs is a good indication that
there is a fault in the circuit being monitored.
Using Tech 2 to help detect intermittent conditions. The
Tech 2 have several features that can be used to
located an intermittent condition. Use the following
features to find intermittent faults:
To check for loss of diagnostic code memory,
disconnect the MAF sensor and idle the engine until the
check engine lamp (MIL=malfunction indicator lamp)
comes on. Diagnostic Trouble Code P0100 should be
stored and kept in memory when the ignition is turned
OFF.
If not, the ECM is faulty. When this test is completed,
make sure that you clear the Diagnostic Trouble Code
P0100 from memory.
An intermittent check engine lamp (MIL=malfunction
indicator lamp) with no stored Diagnostic Trouble Code
may be caused by the following:
Check engine lamp (MIL=malfunction indicator lamp)
wire to ECM short to ground.
Poor ECM grounds. Refer to the ECM wiring
diagrams.
Check for improper installation of electrical options such
as light, cellular phones, etc. Check all wires from ECM
to the ignition control module for poor connections.
Check for an open diode across the A/C compressor
clutch and check for other open diodes (refer to wiring
diagrams in Electrical Diagnosis).
If problem has not been found, refer to ECM connector
symptom tables.
Check the “Broadcast Code” of the ECM, and
compare it with the latest Isuzu service bulletins and/
or Isuzu EEPROM reprogramming equipment to
determine if an update to the ECM's reprogrammable
memory has been released.
This identifies the contents of the reprogrammable
software and calibration contained in the ECM.
If the “Broadcast Code” is not the most current
available, it is advisable to reprogram the ECM's
EEPROM memory, which may either help identify a
hard-to find problem or may fix the problem.
The Service Programming System (SPS) will not allow
incorrect software programming or incorrect calibration
changes.

6E-74 3.5L ENGINE DRIVEABILITY AND EMISSIONS








0.4 Sec 0.4 Sec
.

ON

OFF




3.2 Sec.

1.2 Sec.



3.2 Sec.


0.4 Sec 0.4 Sec
.
ON

OFF


3.2 Sec.

1.2 Sec.


3.2 Sec.



Self-diagnosis Start

Normal Code (12)
Trouble Code (32)


121212141414323232

In case DTC 14 & 32 are stored

Clearing Diagnostic Trouble Codes
Important: Do not clear DTCs unless directed to do so
by the service information provided for each diagnostic
procedure. When DTCs are cleared, the Freeze Frame
and Failure Record data which may help diagnose an
intermittent fault will also be erased from memory.
If the fault that caused the DTC to be stored into
memory has been corrected, the Diagnostic Executive
will begin to count the “warm-up" cycles with no furthe
r
faults detected, the DTC will automatically be cleared
from the ECM memory.
To clear Diagnostic Trouble Codes (DTCs), use the
Tech 2 “clear DTCs" or “clear information" function.
When clearing DTCs follow instructions supplied by the
Tech 2 manufacturer.
When a Tech 2 is not available, DTCs can also be
cleared by disconnecting one of the following sources
for at least thirty (30) seconds.
To prevent system damage, the ignition key must be
“OFF" when disconnecting or reconnecting battery
power.

The power source to the control module. Examples:
fuse, pigtail at battery ECM connectors etc.

The negative battery cable. (Disconnecting the
negative battery cable will result in the loss of othe
r
on-board memory data, such as preset radio tuning).
On-Board Diagnosis (Self-Diagnosis)
1. The Engine Control Module (ECM) conducts a
self-test of most of the wiring and components in
the system each time the key is turned to ON, and
can detect faults in the system while the key is ON.
If a fault is detected, the ECM will store a trouble
code in memory and flash the CHECK ENGINE
indicator to alert the driver.
2. The Diagnostic Trouble Codes (DTC) can be
displayed by shorting together terminals and the
Data Link Connector (DLC) located belo
w
Instrument Panel of drivers side.
The CHECK ENGINE indicator will flash DTC 12
three times, followed by any DTC.If several DTC are
stored, each DTC will be displayed three times. The
DTC will be displayed in numerical order. The DTC
display will continue as long as the DLC is shorted.
Some DTC can cause other DTC to be stored, It is
important to diagnose and repair the lowes
t
numbered DTC first before going on to the highe
r
numbered DTC.

6E–232 ENGINE DRIVEABILITY AND EMISSIONS
SYMPTOM DIAGNOSIS
PRELIMINARY CHECKS
Before using this section, perform the “On-Board
Diagnostic (OBD) System Check” and verify all of the
following items:
The engine control module (ECM) and malfunction
indicator lamp (MIL = Check Engine Lamp) are
operating correctly.
There are no Diagnostic Trouble Code(s) stored.
Tech 2 data is within normal operating range. Refer to
Typical Scan Data Values.
Verify the customer complaint and locate the correct
symptom in the table of contents. Perform the
procedure included in the symptom chart.
VISUAL/PHYSICAL CHECK
Several of the symptom procedures call for a careful
visual/physical check. This can lead to correcting a
problem without further checks and can save valuable
time. This check should include the following items:
ECM grounds for cleanliness, tightness and proper
location.
Vacuum hoses for splits, kinks, and proper
connection, shown on the “Emission Control System
Schematics”. Check thoroughly for any type of leak or
restriction.
Air intake ducts for collapsed or damaged areas.
Air leaks at throttle body mounting area, manifold
absolute pressure (MAP) sensor and intake manifold
sealing surfaces.
Ignition wires for cracking, harness, and carbon
tracking.
Wiring for proper connections, pinches and cuts.
INTERMITTENT
Important: An intermittent problem may or may not turn
on the malfunction indicator lamp (MIL) or store a
Diagnostic Trouble Code. Do NOT use the Diagnostic
Trouble Code (DTC) charts for intermittent problems.
The fault must be present to locate the problem.
Most intermittent problems are cased by faulty electrical
connections or wiring. Perform a careful visual/physical
check for the following conditions.
Poor mating of the connector halves or a terminal not
fully seated in the connector (backed out).
Improperly formed or damaged terminal.
All connector terminals in the problem circuit should
be carefully checked for proper contact tension.
Poor terminal-to-wire connection. This requires
removing the terminal form the connector body to
check.
Ignition coils shorted to ground and arcing at ignition
wires or plugs.MIL (Check Engine Lamp) wire to ECM shorted to
ground.
Poor ECM grounds. Refer to the ECM wiring
diagrams.
Road test the vehicle with a Digital Multimeter
connected to a suspected circuit. An abnormal voltage
when the malfunction occurs is a good indication that
there is a fault in the circuit being monitored.
Using Tech 2 to help detect intermittent conditions. The
Tech 2 has several features that can be used to located
an intermittent condition.
An intermittent MIL (Check Engine Lamp) with no stored
Diagnostic Trouble Code may be caused by the
follow ing:
Ignition coil shorted to ground and arcing at ignition
wires or plugs.
MIL (Check Engine Lamp) wire to ECM short to
ground.
Poor ECM grounds. Refer to the ECM wiring
diagrams.
Check for improper installation of electrical options such
as light, cellular phones, etc. Check all wires from ECM
to the ignition control module for poor connections.
Check for an open diode across the A/C compressor
clutch and check for other open diodes (refer to wiring
diagrams in Electrical Diagnosis).
If problem has not been found, refer to ECM connector
symptom tables.
Check the “Broadcast Code” of the ECM, and
compare it with the latest Isuzu service bulletins and/
or Isuzu EEPROM reprogramming equipment to
determine if an update to the ECM’s reprogrammable
memory has been released.
To check the “Broadcast Code”, connect the Tech 2,
then look for “ID info.” then select “Broadcast Code”.
This should display a 4 character code, such as “XBYA”
(ex ample only).
This identifies the contents of the reprogrammable
software and calibration contained in the ECM.
If the “Broadcast Code” is not the most current
available, it is advisable to reprogram the ECM’s
EEPROM memory, which may either help identify a
hard-to find problem or may fix the problem.
The Service Programming System (SPS) will not allow
incorrect software programming or incorrect calibration
changes.

TRANSFER CONTROL SYSTEM 7D1-1
SECTION 7D1
TRANSFER CONTROL SYSTEM
TABLE OF CONTENTS
PAGE
Service Precaution .................................................................................................... 7D1 - 2
General Description ................................................................................................... 7D1 - 3
System Components ................................................................................................. 7D1 - 5
Parts Location ...................................................................................................... 7D1 - 5
Functions of Switch and Indicator Lamp ................................................................. 7D1 - 11
Parts Location ............................................................................................................ 7D1 - 23
Circuit Diagram .......................................................................................................... 7D1 - 27
Connector List ........................................................................................................... 7D1 - 31
Diagnosis .................................................................................................................... 7D1 - 34
Before determining trouble ................................................................................. 7D1 - 34
Memory erasing procedure ....................................................................................... 7D1 - 40
Diagnosis from symptom .......................................................................................... 7D1 - 41

TRANSMISSION CONTROL SYSTEM (AW30–40LE) (V6 3.5L) 7A2-1
TRANSMISSION
TRANSMISSION CONTROL SYSTEM (AW30–40LE) (V6 3.5L)
CONTENTS

Service Precaution .................................................
7A2-2
General Description ...............................................
7A2-2
Electronic Control Diagram ...............................
7A2-3
Transmission Control Module (TCM) (1/2) ......
7A2-4
Transmission Control Module (TCM) (2/2) ......
7A2-5
TCM Point Table .................................................
7A2-6
TCM Voltage & Resistance Check Sheet .......
7A2-7
Control System Diagram ....................................
7A2-9
Control and Functions ........................................
7A2-10
Gear Shift Control 3rd start ...............................
7A2-10
Mode Type ...........................................................
7A2-10
Mode Selection ....................................................
7A2-10
Comparison of mode ..........................................
7A2-11
3rd start Mode .....................................................
7A2-11
Backup Mode .......................................................
7A2-11
Functions of Input / Output Components ........
7A2-12
CAN bus systems in automatic transmission
control (AW30-40LE) ........................................
7A2-13
High speed CAN bus ..........................................
7A2-13
Diagnosis .................................................................
7A2-13
Electronic Diagnosis ...........................................
7A2-13
Check Trans Indicator ........................................
7A2-13
On Board Diagnostic Check ..............................
7A2-13
"Check Trans" Check .........................................
7A2-14
Tech 2 OBD Connection ....................................
7A2-17
Snapshot Display With TIS2000 .................. 7A2-23
Service Programming System (SPS)............. 7A2-27
OBD Diagnostic Management System ............
7A2-30
16 - Terminal Data Link Connector (DLC) ......
7A2-31
Clear DTC ............................................................
7A2-32
DTC Check ..........................................................
7A2-32
TCM Precaution ..................................................
7A2-32
Information On TCM ...........................................
7A2-32
TCM Diagnostic Trouble Codes ........................
7A2-33
DTC P0560 (FLASHING CODE 25)
System Voltage Error ...........................................
7A2-34

DTC P0602 (FLASHING CODE 63)
Transmission Control Module (TCM)
Programming Error ................................................
7A2-36
DTC P0705 (FLASHING CODE 17)
Transmission Range Sensor Circuit
Malfunction .............................................................
7A2-38
DTC P0712 (FLASHING CODE 15)
Transmission Oil Temperature Sensor
Circuit Low Input ....................................................
7A2-42
DTC P0713 (FLASHING CODE 16)
Transmission Oil Temperature Sensor
Circuit Hight Input ..................................................
7A2-45
DTC P0717 (FLASHING CODE 14)
Input Speed Sensor Signal Error .........................
7A2-48
DTC P0722 (FLASHING CODE 11)
Output Speed Sensor Signal Error .....................
7A2-51
DTC P0743 (FLASHING CODE 33)
Torque Converter Clutch Electrical .....................
7A2-54
DTC P0748 (FLASHING CODE 35)
Pressure Control Solenoid Electrical ..................
7A2-57
DTC P0753 (FLASHING CODE 31)
Shift Solenoid S1 Electrical ..................................
7A2-60
DTC P0758 (FLASHING CODE 32)
Shift Solenoid S2 Electrical ..................................
7A2-63
DTC P1767 (FLASHING CODE 67)
ECM CAN Invalid ...................................................
7A2-66
DTC P1790 (FLASHING CODE 61)
Transmission Control Module ROM
Checksum Error .....................................................
7A2-69
DTC P1791 (FLASHING CODE 62)
Transmission Control Module RAM
Error .........................................................................
7A2-71
DTC U2104 (FLASHING CODE 65)
CAN BUSS OFF ....................................................
7A2-73

ON-VEHICLE SERVICE (AW30 –40LE) 7A3-43

Removal
NOTE: Before removing transmission and transfer
assembly from vehicle, change the transfer mode to
2WD using the 4WD push button switch on dash panel.
1. Disconnect battery ground cable.
2. Raise and support vehicle with suitable stands.
3. Remove front propeller shaft.(4WD only)
NOTE: Apply alignment marks on the flange at both
front and rear sides.
4. Remove rear propeller shaft.
NOTE: Apply alignment marks on the flange at the
differential side.


401RS023
5. Remove the middle exhaust pipe.



RTW37ASH0001

6. Disconnect the transfer harness connectors and the
clips.(4WD only)

Speed sensor
 2W-4W shift actuator
NOTE: Avoid turning the vehicle ignition switch to the
ON position when the 2WD-4WD connector is removed
(battery connected).
If the ignition switch must be turned to the ON position,
the controller must first be removed (memory must be
cleared because the CHECK 4WD INDICATOR will
light).
7. Support transfer case with a transmission jack.(4WD only)
8. Remove the transfer case assembly from the
transmission.(4WD only)
9. Disconnect the shift cable.
10. Remove the fuel pipe clips with the fuel pipes from the brackets and put aside it. Remove the fuel pipe
brakets from the transmission.






P1010010
11. Discinnect the transmission harness connectors
and clips.
12. Remove the oil level gauge and the guide tube.
13. Remove the suspension crossmember.