switch ISUZU TF SERIES 2004 Workshop Manual

6E-66 3.5L ENGINE DRIVEABILITY AND EMISSIONS
 Does it rely on some mechanical/vacuum
device to operate?

Physical:
 Where are the circuit components (componen
t
locators and wire harness routing diagrams):

Are there areas where wires could be
chafed or pinched (brackets or frames)?

Are there areas subjected to extreme
temperatures?

Are there areas subjected to vibration or
movement (engine, transmission or
suspension)?

Are there areas exposed to moisture, road
salt or other corrosives (battery acid, oil o
r
other fluids)?

Are there common mounting areas with
other systems/components?
 Have previous repairs been performed to
wiring, connectors, components or mounting
areas (causing pinched wires between panels
and drivetrain or suspension components
without causing and immediate problem)?
 Does the vehicle have aftermarket or dealer-
installed equipment (radios, telephone, etc.)

Step 2: Isolate the problem
At this point, you should have a good idea of what could
cause the present condition, as well as could not cause
the condition. Actions to take include the following:

Divide (and separate, where possible) the system
or circuit into smaller sections

Confine the problem to a smaller area of the
vehicle (start with main harness connections while
removing panels and trim as necessary in order to
eliminate large vehicle sections from furthe
r
investigation)

For two or more circuits that do not share a
common power or ground, concentrate on areas
where harnesses are routed together o
r
connectors are shared (refer to the following hints)

Hints
Though the symptoms may vary, basic electrical failures
are generally caused by:

Loose connections:
 Open/high resistance in terminals, splices,
connectors or grounds

Incorrect connector/harness routing (usually in
new vehicles or after a repair has been made):

 Open/high resistance in terminals, splices,
connectors of grounds

Corrosion and wire damage:
 Open/high resistance in terminals, splices,
connectors of grounds

Component failure:
 Opens/short and high resistance in relays,
modules, switches or loads


Aftermarket equipment affecting normal operation
of other systems You may isolate circuits by:

Unplugging connectors or removing a fuse to
separate one part of the circuit from another part

Operating shared circuits and eliminating those
that function normally from the suspect circuit

If only one component fails to operate, begin
testing at the component

If a number of components do no operate, begin
tests at the area of commonality (such as powe
r
sources, ground circuits, switches or majo
r
connectors)
What resources you should use
Whenever appropriate, you should use the following
resources to assist in the diagnostic process:

Service manual

Technical equipment (for data analysis)

Experience

Technical Assistance

Circuit testing tools
5d. Intermittent Diagnosis
By definition, an intermittent problem is one that does
not occur continuously and will occur when certain
conditions are met. All these conditions, however, may
not be obvious or currently known. Generally,
intermittents are caused by:

Faulty electrical connections and wiring

Malfunctioning components (such as sticking
relays, solenoids, etc.)

EMI/RFI (Electromagnetic/radio frequency
interference)

Aftermarket equipment
Intermittent diagnosis requires careful analysis of
suspected systems to help prevent replacing good
parts. This may involve using creativity and ingenuity to
interpret customer complaints and simulating all
external and internal system conditions to duplicate the
problem.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-67
What you should do
Step 1: Acquire information
A thorough and comprehensive customer check sheet
is critical to intermittent problem diagnosis. You should
require this, since it will dictate the diagnostic starting
point. The vehicle service history file is another
source for accumulating information about the
complaint.

Step 2: Analyze the intermittent problem
Analyze the customer check sheet and service history
file to determine conditions relevant to the suspect
system(s).
Using service manual information, you must identify,
trace and locate all electrical circuits related to the
malfunctioning system(s). If there is more than one
system failure, you should identify, trace and locate
areas of commonality shared by the suspect circuits.

Step 3: Simulate the symptom and isolate the
problem
Simulate the symptom and isolate the system by
reproducing all possible conditions suggested in Step 1
while monitoring suspected circuits/components
/
systems to isolate the problem symptom. Begin with the
most logical circuit/component.
Isolate the circuit by dividing the suspect system into
simpler circuits. Next, confine the problem into a smalle
r
area of the system. Begin at the most logical point (or
point of easiest access) and thoroughly check the
isolated circuit for the fault, using basic circuit tests.

Hints
You can isolate a circuit by:

Unplugging connectors or removing a fuse to
separate one part of the circuit from another

If only component fails to operate, begin testing
the component

If a number of components do not operate, begin
test at areas of commonality (such as powe
r
sources, ground circuits, switches, main
connectors or major components)

Substitute a known good part from the parts
department or the vehicle system

Try the suspect part in a known good vehicle See
Symptom Simulation Tests on the next page fo
r
problem simulation procedures. Refer to service
manual sections 6E and 8A for information abou
t
intermittent diagnosis. Follow procedures for basic
circuit testing in service manual section 8A.
What resources you should use
Whenever appropriate, you should use the following
resources to assist in the diagnostic process:

Service manual

Bulletins

Digital multimeter (with a MIN/MAX feature)

Tech 2 and Tech 2 upload function

Circuit testing tools (including connecto
r
kits/harnesses and jumper wires)

Experience

Intermittent problem solving simulation methods

Customer complaint check sheet
Symptom Simulation Tests
1. Vibration
This method is useful when the customer complain
t
analysis indicates that the problem occurs when the
vehicle/system undergoes some form of vibration.
For connectors and wire harness, slightly shake
vertically and horizontally. Inspect the connector join
t
and body for damage. Also, tapping lightly along a
suspected circuit may be helpful.
For parts and sensors, apply slight vibration to the par
t
with a light tap of the finger while monitoring the system
for a malfunction.
2. Heat
This method is important when the complaint suggests
that the problem occurs in a heated environment. Apply
moderate heat to the component with a hair drier o
r
similar tool while monitoring the system for a
malfunction.
CAUTION: Care must be take to avoid overheating
the component.
3. Water and Moisture
This method may be used when the complaint suggests
that the malfunction occurs on a rainy day or unde
r
conditions of high humidity. In this case, apply water in
a light spray on the vehicle to duplicate the problem.
CAUTION: Care must be take to avoid directly
exposing electrical connections to water.
4. Electrical loads
This method involves turning systems ON (such as the
blower, lights or rear window defogger) to create a load
on the vehicle electrical system at the same time you
are monitoring the suspect circuit/component.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-73
Intermittent Check Engine Lamp
In the case of an “intermittent" fault, the MIL (“Check
Engine" lamp) may illuminate and then (after three trips)
go “OFF". However, the corresponding diagnostic
trouble code will be stored in the memory. When
unexpected diagnostic trouble codes appear, check fo
r
an intermittent malfunction.
A diagnostic trouble code may reset. Consult the
“Diagnostic Aids" associated with the diagnostic trouble
code. A physical inspection of the applicable sub–
system most often will resolve the problem.
Data Link Connector (DLC)
The provision for communication with the control
module is the Data Link Connector (DLC). The DLC is
used to connect to a Tech 2. Some common uses o
f
the Tech 2 are listed below:

Identifying stored Diagnostic Trouble Codes (DTCs).

Clearing DTCs.

Performing out put control tests.

Reading serial data.








060RW046
Verifying Vehicle Repair
Verification of vehicle repair will be more
comprehensive for vehicles with OBD system
diagnostic. Following a repair, the technician should
perform the following steps:
1. Review and record the Fail Records and/or Freeze
Frame data for the DTC which has been diagnosed
(Freeze Frame data will only be stored for an A or B
type diagnostic and only if the MIL has been
requested).
2. Clear DTC(s).
3. Operate the vehicle within conditions noted in the
Fail Records and/or Freeze Frame data.
4. Monitor the DTC status information for the specific
DTC which has been diagnosed until the diagnostic
test associated with that DTC runs.
Following these steps are very important in verifyin
g
repairs on OBD systems. Failure to follow these steps
could result in unnecessary repairs.
Reading Flash Diagnostic Trouble Codes
The provision for communicating with the Engine
Control Module (ECM) is the Data Link Connecto
r
(DLC). The DLC is located behind the lower front
instrument panel. It is used in the assembly plant to
receive information in checking that the engine is
operating properly before it leaves the plant.
The diagnostic trouble code(s) (DTCs) stored in the
ECM's memory can be read either through a hand-held
diagnostic scanner plugged into the DLC or by counting
the number of flashes of the Check Engine Lamp (MIL)
when the diagnostic test terminal of the DLC is
grounded. The DLC terminal “6" (diagnostic request) is
pulled “Low" (grounded) by jumpering to DLC terminal
“4", which is a ground wire.
This will signal the ECM that you want to “flash" DTC(s),
if any are present. Once terminals “4" and “6" have
been connected, the ignition switch must be moved to
the “ON" position, with the engine not running. At this
point, the “Check Engine" MIL should flash DTC12
three times consecutively.
This would be the following flash, sequence: "flash,
pause, flash?flash, long pause, flash, pause,
flash?flash, long pause, flash, pause, flash?flash". DTC
12 indicates that the ECM's diagnostic system is
operating. If DTC 12 is not indicated, a problem is
present within the diagnostic system itself, and should
be addressed by consulting the appropriate diagnostic
chart in DRIVEABILITY AND EMISSIONS.
Following the output of DTC 12, the “Check Engine" MIL
will indicate a DTC three times if a DTC is present, or i
t
will simply continue to output DTC12. If more than one
DTC three has been stored in the ECM's memory, the
DTC(s) will be output from the lowest to the highest,
with each DTC being displayed three times.
Reading Diagnostic Trouble Codes Using a
TECH 2
The procedure for reading diagnostic trouble code(s) is
to used a diagnostic Tech 2. When reading DTC(s),
follow instructions supplied by Tech 2 manufacturer.
For the 1998 model year, Isuzu dealer service
departments will continue to use Tech 2.

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E-75
TECH 2 CONNECTION



Tech 2 scan tool is used to electrically diagnose the
automatic transmission system and to check the
system. The Tech 2 enhances the diagnosis efficiency
though all the troubleshooting can be done without the
Te c h 2 .
1. Configuration of Tech 2

Tech 2 scan tool kit (No. 7000086), Tech 2
scan tool (No. 7000057) and DLC cable (No.
3000095).

SAE 16/19 adapter (No. 3000098) (3), RS232
loop back connector (No. 3000112) (2) and
PCMCIA card (No. 3000117) (1).
2. Tech 2 Connection

Check the key switch is turn OFF.

Insert the PCMCIA card (1) into the Tech 2 (5).

Connect the SAE 16/19 adapter (3) to the DLC





Turn the key switch of the vehicle ON and press
the “PWR” key of the Tech 2.

Check the display of the Tech 2.
NOTE: Be sure to check that the power is not
supplied to the Tech 2 when attaching or removing
the PCMCIA card.
Diagnosis with TECH 2
If No Codes are Set

Refer to F1: Data Display and identify the electrical
faults that are not indicated by trouble code.

Refer to "SYMPTOM DIAGNOSIS".

If Codes are Set
1. Record all trouble codes displayed by Tech 2 and
check id the codes are intermittent.
2. Clear the codes.
3. Drive the vehicle for a test to reproduce the faulty
status.
4. Check trouble codes again using the Tech 2.
5. If no codes is displayed by test driving, the fault is
intermittent. In this case, refer to "DIAGNOSIS
AIDS".
6. If a code is present, refer to DTC Chartfo
r
diagnosis.
7. Check trouble codes again using the Tech 2.

6E-80 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Tech 2
Parameter
Units Idle 2000rpm Definitions
23 A/C Request (Air
Conditioning) On/Off Off Off This displays the air conditioner request signal. This should display "On" when the air
conditioner switch is switched on.
24 A/C Clutch On/Off Off Off This displays whether the ECM has commanded the A/C compressor clutch "On" or
"Off".
25 EVAP Purge
Solenoid
(Evaporative
Emission) % 50
80 0 This displays the duty signal from the ECM to control the canister purge solenoid
valve.
26 Fuel Trim Cell 49
52 13
17 This displays dependent on engine speed and MAF sensor reading.
A plot of engine speed versus MAF amount is divided into the cells.
Fuel trim cell indicates which cell is currently active.
27 Fuel Pump On/Off On On This displays operating status for the fuel pump main relay.
This should display "On" when the key switch is turned on and while engine is
running.
28 Deceleration Fuel
Cutoff Active/ Inactive Inactive Inactive The ECM will command the deceleration fuel mode when it detects a closed throttle
position while the vehicle is traveling.
While in decreasing fuel mode, the ECM will decrease the amount of fuel delivered
by entering open loop and decreasing the injector pulse width.
29 Power Enrichment Yes/No No No The ECM will command power enrichment mode "Yes" when a large increase in
throttle position and load is detected.
While in power enrichment mode, the ECM will increase the amount of fuel delivered
by entering open loop and increasing the injector pulse width.
30 Vehicle Speed km/h or mph 0 0 This displays vehicle speed.
The vehicle speed is measured by ECM from the vehicle speed sensor.
31 Cam Signal Present/ Missing Present Present This displays input signal from the camshaft position sensor.
When the correct pulse is generated, signal is received.
32 PSP Switch
(Power Steering
Pressure) Normal Pressure /
High Pressure Normal PressureNormal PressureThis displays the power steering pressure signal.
This should display "High Pressure" when the steering is steered.
33 Security Code
Status Programmable/
Not
Programmable Programmable Programmable This should display "Programmable" when the correct security code & secret code
are programmed.
34 Security Code Okay/ Not Okay Okay Okay This should display "Okay" when the security code is correctly accepted.
35 Immobilizer
System Normal /
Abnormal Normal Normal This should display "Normal" when the immobilizer is correctly operated.
36 Malfunction
Indicator Lamp On/Off Off Off This displays operating status for the Check Engine Lamp.
This should display "On" when the Check Engine Lamp is turned on.
37 Time From Start   This displays the engine time elapsed since the engine was started.
If the engine is stopped, engine run time will be reset to 00:00:00

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E -83

MISCELLANEOUS TEST
The state of each circuit can be tested by using
miscellaneous test menus. Especially when DTC cannot
be detected, a faulty circuit can be diagnosed by testing
each circuit by means of these menus.
Even DTC has been detected, the circuit tests using
these menus could help discriminate between a
mechanical trouble and an electrical trouble.
Connect Tech 2 and select "Powertrain", "3.5L V6 6VE1
Hitachi" & "Miscellaneous Test".

F0: Lamps
F0: Malfunction Indicator Lamp
When the Tech 2 is operated, "Malfunction Indicato
r
Lamp (Check Engine Lamp)" is turned on or off.
The circuit is normal if the "Malfunction Indicator Lamp
(Check Engine Lamp)" in the instrument panel is turned
on or off in accordance with this operation.

F1: Relays
F0: Fuel Pump Relay
When the Tech 2 is operated, fuel pump relay signal
turns ON or OFF.
The circuit is normal if fuel pump sound is generated in
accordance with this operation when key switch is
turned ON.

"F1: A/C Clutch Relay"
When the Tech 2 is operated, A/C clutch relay signal
turns ON or OFF.
The circuit is normal if A/C compressor clutch is
energized in accordance with this operation when the
engine is running.

F2: EVAP
F0: Purge Solenoid
When the Tech 2 is operated, duty ratio of EVAP purge
solenoid is changed 10%-by-10%.

Purge Solenoid
Engine Speed 800 RPM
Desired Idle Speed 762 RPM
Engine Coolant Temperature 80

C
Start Up ECT 50

C
Intake Air Temperature 30

C
Throttle Position 0 %
EVAP Purge Solenoid 10 %



Press "Increase" key.

Then, EVAP Purge Solenoid increases

10%-by-10%.


Press "Quit" Key.

F3: IAC System
F0: RPM Control
When the Tech 2 is operated, "Desired Idle Speed"
increases 50rpm-by-50rpm up to 1550rpm.
The circuit is normal if engine speed is changed in
accordance with this operation.
RPM Control
Engine Speed 850 RPM
Desired Idle Speed 850 RPM
Engine Coolant Temperature 80

C
Start Up ECT 50

C
Intake Air Temperature 30

C
Throttle Position 0 %
Desired Idle Speed 850 RPM



Press "Increase" key.

Then, Desired Idle speed increases

50rpm-by-50rpm up to 1550rpm. Engine speed is
also changed by this operation.


Press "Quit" Key.

F0: IAC Control
When the Tech 2 is operated, "Idle Air Control"
increases or decreases 10steps-by-10steps up to
160steps.
The circuit is normal if idle engine speed is changed in
accordance with this operation.
IAC Control
Engine Speed 875 RPM
Desired Idle Speed 762 RPM
Engine Coolant Temperature 80

Start Up ECT 50

Intake Air Temperature 30

Throttle Position 0 %
Idle Air Control 30 Steps



Press "Increase" key.

Then, Idle Air Control increases 10steps-by-
10steps up to 160steps.

Engine speed is also changed by this operation.


Press "Quit" Key.

6E-92 3.5L ENGINE DRIVEABILITY AND EMISSIONS

2.Demand of Data
1.
Connect Tech-2 to the vehicle. When activated b
y
turning on the power of Tech-2, push the "Enter"
switch.
2.
Turn on the ignition switch (without starting the
engine)
3.
In the main menu of Tech 2, push "F1: Service
Programming System (SPS)".
4.
Push "F0: Request Info" of Tech-2.

5.
Where vehicle data has been already saved in
Tech-2, the existing data come on display. In this
instance, as Tech-2 starts asking whether to keep
the data or to continue obtaining anew data from
the control unit, choose either of them.





6.
If you select “continue”, you have to select “Model
Year”, “Vehicle Type”.
7.
After that. then push button and turn Ignition switch
tuned on, off, on following Tech-2 display. Tech-2
will read information from controller after this
procedure.
8.
During obtaining information, Tech-2 is receiving
information from the control unit ECM and TCM
(A/T only) at the same time. With VIN not being
programmed into the new control unit at the time
of shipment, "obtaining information" is not
complete (because the vehicle model, engine
model and model year are specified from VIN). Fo
r
the procedure get additional information on
vehicles, instruction will be provided in dialog form,
when TIS2000 is in operation.
9.
Following instructions by Tech-2, push the "Exit"
switch of Tech-2, turn off the ignition of the vehicle
and turn off the power of Tech-2, thereby removing
from the vehicle.


3.Data Exchange
1.
Connect Tech-2 to P/C, turn on the power and
click the "Next" button of P/C.
2. Check VIN of the vehicle and choose "Next".
3. Select “System Type” for required control unit.


Engine (Programming for ECM or PCM)


Transmission (Programming for TCM)
4.
When a lack of data is asked from among the
following menu, enter accordingly.

Select following Menu


Model Year


Model


Engine type


Transmission type


Destination code (vehicles for general export)*1


Immobilizer
Etc.
* 1: How to read the destination code
"Destination code can be read from service ID Plate
affixed on vehicles, while on service ID plate the
destination code is described at the right-hand edge o
f
Body Type line. In the figure, the destination code can
be read as "RR3" (Australia).

3.5L ENGINE DRIVEABILITY AND EMISSIONS 6E -93





5.
After choosing the data, click the "Next" button.
6.
When all the necessary information is entered, the
"details" of software within the database that
match the entered data will appear fo
r
confirmation. Click the "Program" switch and then
download the new software onto Tech-2.
7. "Data Transfer" comes on display. The progress o
f
downloading will be displayed on the screen in the
form of bar graph.
8.
Upon finishing the data transfer, turn off the powe
r
of Tech-2, removing from P/C.


4. Programming of ECM
1.
Check to see if batteries are fully charged, while
ABS connectors shall be removed from the
vehicle.
2.
Connect Tech-2 to Vehicle Diagnostic Connectors.
3.
Turn on the power of Tech-2 and the title screen
comes on display.
4.
Turn on the ignition (without allowing the engine to
start)
5.
On the title screen of Tech-2, push the "Enter"
button.
6.
Choose "F1: Service Programming System" on the
main screen and then choose "F1: Program ECU".
7.
While data is being transferred, "Programing in
Progress" will be displayed on the Tech-2 screen.
8.
Upon finishing the data transfer, Tech-2 will
display "Reprogramming was Successful". Push
the "Exit" button to bring program to completion.















9.
Following "Procedure 2: Demand of Data", try ove
r
again "Information Obtaining" and check to confirm
if the data has been correctly re-loaded.
10. Upon finishing confirmation, turn off the ignition o
f
the vehicle and then turn off the power of Tech-2,
removing from the vehicle.

6E-106 3.5L ENGINE DRIVEABILITY AND EMISSIONS

FUEL INJECTOR COIL TEST
PROCEDURE AND FUEL INJECTOR
BALANCE TEST PROCEDURE




Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart:
2.
Relieve the fuel pressure by connecting the 5–
8840–0378–0 Fuel Pressure Gauge to the fuel
pressure connection on the fuel rail.
CAUTION: In order to reduce the risk of fire and
personal injury, wrap a shop towel around the fuel
pressure connection. The towel will absorb any fuel
leakage that occurs during the connection of the
fuel pressure gauge. Place the towel in an approved
container when the connection of the fuel pressure
gauge is complete.

Place the fuel pressure gauge bleed hose in an
approved gasoline container.

With the ignition switch “OFF," open the valve on
the fuel pressure gauge.


3.
Record the lowest voltage displayed by the DVM
after the first second of the test. (During the first
second, voltage displayed by the DVM may be
inaccurate due to the initial current surge.)

Injector Specifications:

Resistance Ohms Voltage Specification at
10

C

35
C (50
F

95
F)
11.8 – 12.6 5.7 – 6.6


The voltage displayed by the DVM should be within
the specified range.
 The voltage displayed by the DVM may increase
throughout the test as the fuel injector windings
warm and the resistance of the fuel injecto
r
windings changes.
 An erratic voltage reading (large fluctuations in
voltage that do not stabilize) indicates an
intermittent connection within the fuel injector.
5.
Injector Specifications:




Highest Acceptable
Voltage Reading
Above/Below 35

C/10
C
(95

F/50
F) Acceptable Subtracted
Value
9.5 Volts 0.6 Volts
7.
The Fuel Injector Balance Test portion of this chart
(Step 7 through Step 11) checks the mechanical
(fuel delivery) portion of the fuel injector. An engine
cool-down period of 10 minutes is necessary in
order to avoid irregular fuel pressure readings due
to “Hot Soak" fuel boiling.

6E-108 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Injector Coil Test Procedure (Steps 1-6) and Injector Balance Test Procedure
(Steps 7-11)

Step Action Value(s) YES NO
1
Was the “On-Board Diagnostic (OBD) System Check"
performed?
— Go to Step 2 Go to OBD
System Check
2 1. Turn the engine “OFF."
In order to prevent flooding of a single cylinder and
possible engine damage, relieve the fuel pressure
before performing the fuel injector coil test procedure.
2. Relieve the fuel pressure. Refer to Test
Description Number 2.
3. Connect the 5–8840–2618–0 Fuel Injector Tester
to B+ and ground, and to the 5–8840–2635–0
Injector Switch Box.
4. Connect the injector switch box to the gray fuel
injector harness connector located at the rear of
the air cleaner assembly.
5. Set the amperage supply selector switch on the
fuel injector tester to the “Coil Test" 0.5 amp
position.
6. Connect the leads from the Digital Voltmeter
(DVM) to the injector tester. Refer to the
illustrations associated with the test description.
7. Set the DVM to the tenths scale (0.0).
8. Observe the engine coolant temperature.
Is the engine coolant temperature within the specified
values? 10
C (50
F) to
35
C (95
F) Go to Step 3 Go to Step 5
3
1. Set injector switch box injector #1.
2. Press the “Push to Start Test" button on the fuel
injector tester.
3. Observe the voltage reading on the DVM.
Important: The voltage reading may rise during the
test.
4. Record the lowest voltage observed after the first
second of the test.
5. Set the injector switch box to the next injector and
repeat steps 2, 3, and 4.
Did any fuel injector have an erratic voltage reading
(large fluctuations in voltage that did not stabilize) or a
voltage reading outside of the specified values? 5.7-6.6 V Go to Step 4 Go to Step 7
4 Replace the faulty fuel injector(s). Refer to Fuel
Injector.
Is the action complete? — Go to Step 7 —