2004 ISUZU TF SERIES circuit diagram

ENGINE DRIVEABILITY AND EMISSIONS 6E–63
3. Check Bulletins and
Troubleshooting Hints
NOTE: As estimated 30 percent of successful vehicle
repairs are diagnosed with this step!
What you should do
You should have enough information gained from
preliminary checks to accurately search for a bulletin
and other related service information. Some service
manual sections provide troubleshooting hints that
match symptoms with specific complaints.
What resources you should use
You should use the following resources for assistance in
checking for bulletins and troubleshooting hints:
Printed bulletins
Access ISUZU Bulletin Web site.
Videotapes
Service manual
4. Perform Service Manual
Diagnostic Checks
What you should do
The “System Checks” in most service manual sections
and in most cells of section 8A (electrical) provide you
with:
A systematic approach to narrowing down the
possible causes of a system fault
Direction to specific diagnostic procedures in the
service manual
Assistance to identify what systems work correctly
What resources you should use
Whenever possible, you should use the following
resources to perform service manual checks:
Service manual
Technical equipment (for viewing DTCs and
analyzing data)
Digital multimeter and circuit testing tools
Other tools as needed
5a and 5b. Perform Service Manual
Diagnostic Procedures
NOTE: An estimated 40 percent of successful vehicle
repairs are diagnosed with these steps!
What you should do
When directed by service manual diagnostic checks,
you must then carefully and accurately perform the
steps of diagnostic procedures to locate the fault relatedto the customer complaint.
What resources you should use
Whenever appropriate, you should use the following
resources to perform service manual diagnostic
procedures:
Service manual
Technical equipment (for analyzing diagnostic data)
Digital multimeter and circuit testing tools
Essential and special tools
5c. Technician Self Diagnoses
When there is no DTC stored and no matching
symptom for the condition identified in the service
manual, you must begin with a thorough understanding
of how the system(s) operates. Efficient use of the
service manual combined with you ex perience and a
good process of elimination will result in accurate
diagnosis of the condition.
What you should do
Step 1: Identify and understand the suspect
circuit(s)
Having completed steps 1 through 4 of the Strategy
Based Diagnostics chart, you should have enough
information to identify the system(s) or sub-system(s)
involved. Using the service manual, you should
determine and investigate the following circuit
characteristics:
Electrical:
–How is the circuit powered (power distribution
charts and/or fuse block details)?
–How is the circuit grounded (ground distribution
charts)?
–How is the circuit controlled or sensed (theory of
operation):
–If it is a switched circuit, is it normally open or
normally closed?
–Is the power switched or is the ground
switched?
–Is it a variable resistance circuit (ECT sensor
or TP sensor, for ex ample)?
–Is it a signal generating device (MAF sensor of
VSS, for example)?
–Does it rely on some mechanical/vacuum
device to operate?
Physical:
–Where are the circuit components (component
locators and wire harness routing diagrams):
–Are there areas where wires could be chafed
or pinched (brackets or frames)?
–Are there areas subjected to ex treme
temperatures?

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.

6E–248 ENGINE DRIVEABILITY AND EMISSIONS
CUTS OUT, MISSES SYMPTOM
DEFINITIONS: Steady pulsation or jerking that follows
engine speed; usually more pronounced as engine load
increases.
Step Action Value(s) Yes No
1Was the “On-Board Diagnostic (OBD) System Check”
performed?—Go to Step 2Go to OBD
System Check
2 1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?—Verify repair Go to Step 3
3 Was a visual/physical check performed?
—Go to Step 4Go to Visual /
physical Check.
4 Check the ECM grounds to verify that they are clean
and tight. Refer to the ECM wiring diagrams in
Electrical Diagnosis.
Was a problem found?—Verify repair Go to Step 5
5 Check for a loose or short circuit of ignition coil
module voltage feed.
Was a problem found?—Verify repair Go to Step 6
6 Check for a loose or short circuit of ignition coil
module ground.
Was a problem found?—Verify repair Go to Step 7
7 Visually/physically inspect all spark plug high-tension
cables. Check for the following conditions:
Verify that the resistance of all spark plug high-
tension cables are less than the specified value.
Verify that the all spark plug high-tension cables are
correctly fitted to eliminate cross-fitting.
Verify that the all spark plug high-tension cables are
not arcing to ground.
Spraying the spark plug high-tension cables with a
light mist of water may help locate an intermittent
problem.
Was a problem found?#1 cyl. 4.4k

#2 cyl. 3.6k

#3 cyl. 3.1k

#4 cyl. 2.8k
Verify repair Go to Step 7
8 Check the CKP sensor wire, shield wire, or installation
condition.
Was a problem found?—Verify repair Go to Step 9
9 Monitor “B1S1 (Bank 1 Sensor 1) Status” on the Tech
2.
Is the “B1S1 (Bank 1 Sensor 1) Status” in the rich
condition?—Go to Step 10Go to Step 11

IMMOBILIZER SYSTEM 11A-1

SECTION 11A
IMMOBILIZER SYSTEM
CONTENTS

Service Precaution.................................................
11A-2
General Description...............................................
11A-3
What happens without proper transponder
operation? ..........................................................
11A-6
No proper transponder is available, what
should be done for the system? ......................
11A-6
Caution to the operation.....................................
11A-6
Summary of operation........................................
11A-6
What your organization should provide for
your customer ....................................................
11A-6
Car Pass .............................................................
11A-6
Security code management ..............................
11A-6
Essential tool (Scan tool : Tech-2) ..................
11A-6
Circuit Diagram .................................................
11A-7
Parts Location.........................................................
11A-10
Immobilizer control unit (ICU); For Electronic
Control Engine (6VE1, C24SE, 4JH1-TC,
4JA1-TC) .......................................................... 11A-11
Pin-outs; For Electronic Control Engine
(6VE1, C24SE, 4JH1-TC, 4JA1-TC)...............
11A-12
Immobilizer control unit (ICU); Mechanical
Control Engine (4JA1-T) .................................. 11A-13
Immobilizer coil (Antenna) ...................................
11A-15
Transponder (Key) ............................................ 11A-15
Immobilizer warning lamp ................................. 11A-15
Engine control module (ECM) .......................... 11A-15
Car Pass Card .................................................. 11A-16
Loss of car pass card.........................................
11A-16
Instructions on Filling Out the form "Data
request, car pass" .............................................
11A-16
Important Instructions ........................................
11A-17
lmportant information on Programming .............
11A-19
Security code ......................................................
11A-19
Entering a code ..................................................
11A-19
Transponder (Key) .............................................
11A-19
Important .............................................................
11A-19
Tech-2 Scan Tool ..................................................
11A-20
Tech-2 Features .................................................
11A-21
Getting Started ...................................................
11A-21
Operating Procedure .........................................
11A-22
Menu ....................................................................
11A-23
DTC ......................................................................
11A-23
Clear DTC Information .......................................
11A-23
Tech-2 Data Display ...........................................
11A-23
Check Vehicle Identification Number (VIN) ....
11A-23
Reset Immobilizer (Reset Immobilizer
Control Unit) .......................................................
11A-23
Reset Engine Control Module (Reset ECM) ...
11A-24
Erase transponder key .......................................
11A-24
Programming Immobilizer Function .................
11A-25
Programming ICU ...............................................
11A-26
Programming ECM .............................................
11A-27
Programming ICU and ECM .............................
11A-28
Transponder program ........................................
11A-28
Data List ...............................................................
11A-30
Diagnostic procedure ............................................
11A-31
Clearing Diagnostic Trouble Codes ....................
11A-31
Verifying Vehicle Repair ........................................
11A-31
Diagnostic Aids ......................................................
11A-31
Check the condition for system parts ..............
11A-31
Check the Electro-Magnetic Interference
(EMI) ....................................................................
11A-31
Check the other items ........................................
11A-31
Check the operation ...........................................
11A-31
Diagnostic Trouble Code (DTC) list ....................
11A-32
IMMOBILIZER SYSTEM CHECK ........................
11A-33
NO IMMOBILIZER WARNING LAMP .................
11A-36
IMMOBILIZER WARNING LAMP ON STEADY 11A-37
B0001 REPLACE ELECTRONIC CONTROL
UNIT (ECU) (IMMOBILIZER FAULT) ................
11A-38
B0002 IMMOBILIZER NOT PROGRAMMED ....
11A-39
B0003 TRANSPONDER KEY PROBLEM ..........
11A-40
B0004 IMMOBILIZER COIL CIRCUIT
(ANTENNA COIL FAULT) ...................................
11A-42
B0005 COMMUNICATION LINE W VOLTAGE
LOW .......................................................................
11A-43
B0006 COMMUNICATION LINE W VOLTAGE
HIGH .......................................................................
11A-44
B0007 NO ENGINE REQUEST RECEIVED ......
11A-45
B0008 WRONG TRANSPONDER KEY .............
11A-47
B0009 NO TRANSPONDER KEY
PROGRAMMED ...................................................
11A-48

IMMOBILIZER SYSTEM 11A-7

Circuit Diagram





Gasoline Engine (6VE1, C24SE)




RAW4B0LF000501

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

TRANSFER CONTROL SYSTEM 7D1-27
CIRCUIT DIAGRAM (6VE1)


RTW 48AXF007201

7D1-28 TRANSFER CONTROL SYSTEM
CIRCUIT DIAGRAM (C24SE)


RTW 48AXF031601