2002 ISUZU AXIOM ignition

6E±41
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Tech 2 Features
1. Tech 2 is a 12 volt system. Do not apply 24 volts.
2. After connecting and/or installing the Vehicle
Communications Interface (VCI) module, PCMCIA
card and DLC connector to the Tech 2, connect the
tool to the vehicle DLC.
3. Make sure the Tech 2 is OFF when removing or
installing the PCMCIA card.
4. The PCMCIA card has a capacity of 10 Megabytes
which is 10 times greater than the memory of the Tech
1 Mass Storage Cartridge.
5. The Tech 2 has the capability of two snapshots.
6. The PCMCIA card is sensitive to magnetism and
static electricity, so care should be taken in the
handling of the card.
7. The Tech 2 can plot a graph when replaying a
snapshot.
8. Always return to the Main Menu by pressing the EXIT
key several times before shutting down.
9. To clear Diagnostic Trouble Codes (DTCs), open
Application Menu and press ªF1: Clear DTC Infoº.
Getting Started

Before operating the Isuzu PCMCIA card with the
Tech 2, the following steps must be performed:
1. Insert the Isuzu system PCMCIA card (1) into the
Tech 2 (5).
2. Connect the SAE 16/19 adapter (3) to the DLC cable
(4).
3. Connect the DLC cable to the Tech 2 (5)
4. Make sure the vehicle ignition is off.
5. Connect the Tech 2 SAE 16/19 adapter to the vehicle
DLC.
826RW002
6. Turn on the vehicle ignition.7. Power the Tech 2 ON and verify the Tech 2 power up
display.
060RW009
NOTE: The RS232 Loop back connector is only to use for
diagnosis of Tech 2. Refer to user guide of the Tech 2.

6E±43
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Menu

The following table shows which functions are used
for the available equipment versions.
060R100018
DTC Modes
060R100077
On OBD II vehicles there are options available in Tech 2
DTC mode to display the enhanced information available.
After selecting DTC, the following menu appears:
1. Read DTC Info by Priority
2. Freeze Frame
3. Fail Records (not all applications)
4. DTC Info
5. Clear Info
060RW223
The following is a brief description of each of the sub
menus in DTC Info and DTC. The order in which they
appear here is alphabetical and not necessarily the way
they will appear on the Tech 2.
DTC Information Mode
Use the DTC info mode to search for a specific type of
stored DTC information.
DTC Status
This selection will display any DTCs that have not run
during the current ignition cycle or have reported a test
failure during this ignition up to DTCs. DTC tests which
run and pass will cause that DTC number to be removed
from Tech 2 screen.
Fail This Ignition
This selection will display all DTCs that have failed during
the present ignition cycle.
History
This selection will display only DTCs that are stored in the
PCM's history memory. It will display all type A and B
DTCs that have requested the MIL and have failed within
the last 40 warm-up cycles. In addition, it will display all
type C and type D DTCs that have failed within the last 40
warm-up cycles.
Last Test Failed
This selection will display only DTCs that have failed the
last time the test run. The last test may have run during a
previous ignition cycle if a type A or type B DTC is
displayed. For type C and type D DTCs, the last failure
must have occurred during the current ignition cycle to
appear as Last Test Fail.
MILSVC or Message Request
This selection will display only DTCs that are requesting
the MIL. Type C and type D DTCs cannot be displayed
using this option. This selection will report type B DTCs
only after the MIL has been requested.

6E±46
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Relays Test
This test is conducted to check Fuel Pump Relay and A/C
Clutch for proper operation.
Tech 2 must be used for this test.
Test Procedure:
1. Connect Tech 2 to the vehicle DLC.
2. Ignition SW is ªOnº.
3. Select F3: Miscellaneous Test in the Application
Menu.
060R100078
4. Select F1:Relay Test in the Miscellaneous Test.
060RY00081
5. Select F0:Fuel Pump Relay.
060RX021
6. Push ªOnº soft key.
060RY00093
7. Control Fuel Pump Relay and check data list.
8. If the data list changes, the Fuel Pump Relay is
normal.
9. Select F1:A/C Clutch Relay.
10. Run the Engine at idle.

6E±48
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
6. Push ªDecreaseº or ªIncreaseº soft key.
060RY00095
7. Control EVAP Purge Solenoid and check a data list.
8. If the data list changes, the Purge Solenoid is normal.
9. Turn engine off, turn ignition SW ªOnº.
10. Select F1:EVAP Vent Solenoid.
060RX025
11. Push ªOnº or ªOffº soft key.
060RY00096
12. Control EVAP Vent Solenoid and check data list.
13. If the data list changes, the EVAP Vent Solenoid is
normal.
Fuel System Test
This test is conducted check Fuel system for proper
operation.
Tech 2 must be used for this test.
Test Procedure:
1. Connect Tech 2 to the vehicle DLC.
2. Ignition SW is ªOnº.
3. Select F3: Miscellaneous Test in the Application
Menu.
060R100078

6E±50
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
10. Push ªResetº soft key.
060RY00098
11. Select F2: O2-Loop status.
060R200071
12. This test is check the ªClosed Loop Statusº
performance.13. Push ªOpen Loopº or ªClosed Loopº soft key.
060RY00099
14. Control O2-Loop and check data list.
15. If data list changes, the O2-Loop is normal.
Instruments Test
This test is conducted check Instruments for proper
operation.
Tech 2 must be used for this test.
Test Procedure:
1. Connect Tech 2 to the vehicle DLC.
2. Ignition SW is ªOnº.
3. Select F3: Miscellaneous Test in the Application
Menu.
060R100078

6E±53
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
2. Ignition SW is ªOnº.
060RY00104
3. Select F3: Miscellaneous Test in the Application
Menu.
060R100078
4. Select F6: Variable Intake Manifold Solenoid Test.
060RY00085
5. Push ªOnº or ªOffº soft key.
060RX028
6. Control VIM Solenoid check data list.
7. If data list changes, the VIM Solenoid is normal.

6E±58
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

For the 3.5L w/automatic transmission, the
pre-catalyst sensors are designated Bank 1 HO2S 1
and Bank 2 HO2S 1. The post-catalyst sensors are
Bank 1 HO2S 2 and Bank 2 HO2S 2.
Catalyst Monitor Outputs
The catalyst monitor diagnostic is sensitive to the
following conditions:

Exhaust leaks

HO2S contamination

Alternate fuels
Exhaust system leaks may cause the following:

Preventing a degraded catalyst from failing the
diagnostic.

Causing a false failure for a normally functioning
catalyst.

Preventing the diagnostic from running.
Some of the contaminants that may be encountered are
phosphorus, lead, silica, and sulfur. The presence of
these contaminants will prevent the TWC diagnostic from
functioning properly.
Three-Way Catalyst Oxygen Storage Capacity
The Three-Way catalyst (TWC) must be monitored for
efficiency. To accomplish this, the control module
monitors the pre-catalyst HO2S and post-catalyst HO2S
oxygen sensors. When the TWC is operating properly,
the post-catalyst oxygen sensor will have significantly
less activity than the pre-catalyst oxygen sensor. The
TWC stores and releases oxygen as needed during its
normal reduction and oxidation process. The control
module will calculate the oxygen storage capacity using
the difference between the pre-catalyst and post catalyst
oxygen sensor's voltage levels. If the activity of the
post-catalyst oxygen sensor approaches that of the
pre-catalyst oxygen sensor, the catalyst's efficiency is
degraded.
Stepped or staged testing level allow the control module
to statistically filter test information. This prevents falsely
passing or falsely failing the oxygen storage capacity test.
The calculations performed by the on-board diagnostic
system are very complex. For this reason, post catalyst
oxygen sensor activity should not be used to determine
oxygen storage capacity unless directed by the service
manual.
Two stages are used to monitor catalyst efficiency.
Failure of the first stage will indicate that the catalyst
requires further testing to determine catalyst efficiency.
The seconds stage then looks at the inputs for the pre and
post catalyst HO2S sensors more closely before
determining if the catalyst is indeed degraded. This
further statistical processing is done to increase the
accuracy of oxygen storage capacity type monitoring.
Failing the first (stage 1) test DOES NOT indicate a failed
catalyst. The catalyst may be marginal or the fuel sulfur
content could be very high.Aftermarket HO2S characteristics may be different from
the original equipment manufacturer sensor. This may
lead to a false pass or a false fail of the catalyst monitor
diagnostic. Similarly, if an aftermarket catalyst does not
contain the same amount of cerium as the original part,
the correlation between oxygen storage and conversion
efficiency may be altered enough to set a false DTC.
Misfire Monitor Diagnostic Operation
Misfire Monitor Diagnostic Operation
Misfire is monitored as a function of the combustion
quality (CQ) signals generated from the ignition current
sense system. Combustion signals represent the degree
of combustion in each cylinder. Misfire is detected when
the combustion signal is below a predetermined value.
The misfire ratio is calculated once every 100 engine
cycles. For example, on a 6-cylinder engine, 600 ignition
plug sparks occur every 100 cycles and if a misfire occurs
12 times during that time, the misfire is 12/600 y 100 = 2
%.
Misfire Counters
Whenever a cylinder misfires, the misfire diagnostic
counts the misfire and notes the crankshaft position at the
time the misfire occurred. These ªmisfire countersº are
basically a file on each engine cylinder. A current and a
history misfire counter are maintained for each cylinder.
The misfire current counters (Misfire Cur #1-6) indicate
the number of firing events out of the last 100 cylinder
firing events which were misfires. The misfire current
counter will display real time data without a misfire DTC
stored. The misfire history counters (Misfire Hist #1-6)
indicate the total number of cylinder firing events which
were misfires. The misfire history counters will display 0
until the misfire diagnostic has failed and a DTC P0300 is
set. Once the misfire DTC P0300 is set, the misfire
history counters will be updated every 100 cylinder firing
events. A misfire counter is maintained for each cylinder.
If the misfire diagnostic reports a failure, the diagnostic
executive reviews all of the misfire counters before
reporting DTC. This way, the diagnostic executive
reports the most current information.
When crankshaft rotation is erratic, a misfire condition will
be detected. Because of this erratic condition, the data
that is collected by the diagnostic can sometimes
incorrectly identify which cylinder is misfiring. Misfires are
counted from more than one cylinder. Cylinder #1 has the
majority of counted misfires. In this case, the Misfire
Counters would identify cylinder #1 as the misfiring
cylinder. The misfires in the other counters were just
background noise caused by the erratic misfire rotation of
the crankshaft. If the number of accumulated misfires is
sufficient for the diagnostic to identify a true misfire, the
diagnostic will set DTC P0300 ± Misfire Detected.
Use diagnostic equipment to monitor misfire counter data
on OBD II-compliant vehicles. Knowing which specific
cylinder(s) misfired can lead to the root cause, even when
dealing with a multiple cylinder misfire. Using the
information in the misfire counters, identify which
cylinders are misfiring. If the counter indicate cylinders

6E±60
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
On-Board Diagnostic (OBD II) System Check
060R200048
Circuit Description
The on-board diagnostic system check is the starting
point for any driveability complaint diagnosis. Before
using this procedure, perform a careful visual/physical
check of the PCM and engine grounds for cleanliness and
tightness.
The on-board diagnostic system check is an organized
approach to identifying a problem created by an
electronic engine control system malfunction.
Diagnostic Aids
An intermittent may be caused by a poor connection,
rubbed±through wire insulation or a wire broken inside the
insulation. Check for poor connections or a damaged
harness. Inspect the PCM harness and connector for
improper mating, broken locks, improperly formed or
damaged terminals, poor terminal-to-wire connection,
and damaged harness.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart:
1.The MIL (ªCheck Engine lampº) should be ªONº
steady with the ignition ªON º and the engine ªOFFº.
If not, the ªNo MILº chart should be used to isolate
the malfunction.
2.The RPL (ªReduced Power lampº) should be ªONº
steady with the ignition ªON ºand the engine ªOFFº.
If not, the ªNo RPLºchart should be used to isolate
the malfunction.3.Checks the Class 2 data circuit and ensures that the
PCM is able to transmit serial data.
4.This test ensures that the PCM is capable of
controlling the MIL (ªCheck Engine lampº) and the
MIL (ªCheck Engine lampº) driver circuit is not
shorted to ground.
5.This test ensures that the PCM is capable of
controlling the RPL (ªReduced Power lampº) and
the RPL (ªReduced Power lampº) driver circuit is not
shorted to ground.
7.Check the DTCs (System ,Volts Supply circuit).
8.Check the DTCs (PCM{Software} detect Errors).
11.If the engine will not start, the Cranks But Will Not
Run chart should be used to diagnose the condition.
14.A Tech 2 parameter which is not within the typical
range may help to isolate the area which is causing
the problem.
15.This vehicle is equipped with a PCM which utilizes
an electrically erasable programmable read only
memory (EEPROM). When the PCM is replaced,
the new PCM must be programmed. Refer to PCM
Replacement and Programming Procedures in
Powertrain Control Module (PCM) and Sensors
of
this section.
10. If the starter motor will not start, the starter control
system chart should be used to diagnose the
condition.