2002 ISUZU AXIOM display

6E±232
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0174 ± Fuel Trim System Lean Bank 2

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Are any DTCs set other than P0174 and P0171?
Ð
Go to the
applicable
DTC charts
and repair the
other DTCs
before
proceeding
with this
chart.
Go to Step 3
31. Start the engine and operate the vehicle in ªclosed
loopº.
2. Observe the ªBANK 2 L.T. FUEL TRIMº display on
the Tech 2.
Is the displayed values greater than the specified
values?
L.T. Fuel
Trim: +20%
Go to Step 5Go to Step 4
41. Review and record Tech 2 Failure Records data.
2. Clear the DTC P0171/P0174 and operate the
vehicle to duplicate the Failure Records conditions.
3. Monitor the Tech 2 ªDTCº info for DTC P0174 while
operating the vehicle to duplicate the Failure
Records conditions.
4. Continue operating the vehicle until the DTC P0174
test runs.
5. Note the test result.
Does the Tech 2 indicate DTC P0174 failed this
ignition?
ÐGo to Step 5
The lean
condition is
not present.
If a
driveability
symptom still
exists, refer
to
Symptoms
section.
5Was DTC P0171 also set?ÐGo to Step 6Go to Step 15
6Visually and physically inspect the vacuum hoses for
disconnections, splits, kinks, improper routing and
improper connections and repair any problem found.
Did your inspection reveal a problem requiring repair?
ÐVerify repair Go to Step 7
7Visually and physically inspect the crankcase
ventilation valve for proper installation and repair any
problem found (refer to
Crankcase Ventilation
System
).
Did your inspection reveal a problem requiring repair?
ÐVerify repairGo to Step 8
81. Inspect the MAF sensor inlet screen for damage or
for the presence of foreign objects which may
partially block the air flow sample through the MAF
sensor.
2. Correct any problem that is found as necessary.
Did your inspection of the MAF sensor reveal a
condition requiring repair?
ÐVerify repairGo to Step 9
9Start the engine and note the idle quality.
Is a high or unsteady idle being experienced?
ÐGo to Step 10Go to Step 11

6E±233
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0174 ± Fuel Trim System Lean Bank 2

 
StepNo Ye s Value(s) Action
101. Visually and physically inspect the throttle body,
intake manifold, EGR valve and the EGR feed pipe
for vacuum leaks.
2. Repair any vacuum leaks as necessary.
Did your inspection reveal a vacuum leak?
ÐVerify repairGo to Step 11
11Check the fuel for excessive water, alcohol, or other
contaminants (see
Diagnosis in Engine Fuel for
procedure) and correct the contaminated fuel condition
is present (see
Engine Fuel).
Was the fuel contaminated?
ÐVerify repairGo to Step 12
121. Visually and physically inspect the PCM injector
grounds, power grounds and sensor grounds to
ensure that they are clean, tight, and in their proper
locations.
2. If a faulty ground condition is present, correct it as
necessary.
Did your inspection reveal a condition requiring repair?
ÐVerify repairGo to Step 13
131. Disconnect the MAF sensor electrical connector.
2. Operate the vehicle in ªclosed loopº while
monitoring the ªBANK 2 S.T. FUEL TRIMº displayed
on the Tech 2.
Does the ªBANK 2 S.T. FUEL TRIMº value decrease to
near the specified value?
0%Go to Step 19Go to Step 14
14Perform the procedure in the ºFuel System Pressure
Testº and repair fuel system problem if necessary.
Did the Fuel System Pressure Test isolate a condition
requiring repair?
ÐVerify repairGo to Step 15
151. Visually and physically inspect the intake manifold,
injector O-rings, EGR adapter, EGR valve and the
EGR feed pipes for vacuum leaks.
2. Repair any problem that is found.
Did your inspection reveal a problem?
ÐVerify repairGo to Step 16
16Visually and physically inspect the Bank 2 exhaust
manifold for leaks and loose or missing hardware and
correct any problem found.
Did your inspection reveal a problem?
ÐVerify repairGo to Step 17
17Perform the ªInjector Balance Testº and correct any
problem found (refer to
Fuel Metering System).
Did the Injector Balance Test isolate a problem?
ÐVerify repair Go to Step 18
181. Visually and physically inspect the Bank 2 HO2S 1
to ensure that it is installed securely and that the
Bank 2 HO2S 1 pigtail and wiring harness are not
contacting the exhaust or otherwise damaged.
2. If a problem is found, correct it as necessary.
Did your inspection reveal a problem?
ÐVerify repair
Refer to
Diagnostic
Aids
19Replace the MAF sensor.
Is the action complete?
ÐVerify repairÐ

6E±235
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

A history DTC P0175 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0175 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.
Diagnostic Aids
Check for the following conditions:

Poor connection at PCM ± Inspect harness connectors
for backed -out terminals, improper mating, broken
locks, improperly formed or damaged terminals, and
poor terminal-to-wire connection.

Damaged harness ± Inspect the wiring harness for
damage. If the harness appears to be OK, observe the
Bank 2 HO2S 1 display on the Tech 2 while moving
connectors and wiring harnesses related to the engine
harness. A change in the display will indicate the
location of the fault.
Reviewing the Failure Records Vehicle mileage since the
diagnostic test last failed may help determine how oftenthe condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. DTCs other than P0172 and P0175 may indicate a
condition present which may cause a lean condition.
If this is the case, repairing the condition which
caused the other DTC will most likely correct the
DTC P0172/P0175.
4. If the DTC P0175 test passes while the Failure
Records conditions are being duplicated, the rich
condition is intermittent. Refer to
Diagnostic Aids or
Symptoms for additional information on diagnosing
intermittent problems.
DTC P0175 ± Fuel Trim System Rich Bank 2

StepActionValue(s)Ye sNo
1Was the ºOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Are any DTCs set other than P0172 and P0175?
Ð
Go to the
applicable
DTC charts
and repair the
other DTCs
before
proceeding
with this
chart.
Go to Step 3
31. Start the engine and operate the vehicle in ªclosed
loopº.
2. Observe the ªBANK 2 L.T. FUEL TRIMº display on
the Tech 2.
Is the displayed value more negative than the specified
value?
L.T. Fuel
Trim: ±15%
(auto. trans.)
OR ±12%
(man. trans.)
Go to Step 5Go to Step 4
41. Review and record the Tech 2 Failure Records data.
2. Clear the DTC P0172/P0175 and operate the
vehicle to duplicate the Failure Records conditions.
3. Monitor the Tech 2 ªDTCº info for DTC P0175 while
operating the vehicle to duplicate the Failure
Records conditions.
4. Continue operating the vehicle until the DTC P0175
test runs.
5. Note the test result.
Does the Tech 2 indicate DTC P0175 failed this
ignition?
ÐGo to Step 5
The rich
condition is
not present.
If a
driveability
symptom still
exists, refer
to
Symptoms.
5Was DTC P0172 also set?ÐGo to Step 6Go to Step 15
6Visually and physically inspect the air filter element and
replace it if necessary.
Did the air filter require replacement?
ÐVerify repairGo to Step 7

6E±236
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0175 ± Fuel Trim System Rich Bank 2

 
StepNo Ye s Value(s) Action
7Visually and physically inspect the air intake duct for
collapse or restriction and repair if necessary.
Did your inspection reveal a problem requiring repair?
ÐVerify repairGo to Step 8
8Inspect the MAF sensor inlet screen for damage or for
the presence of foreign objects which may partially
block air flow through the screen and correct any
problem found.
Did your inspection of the MAF sensor reveal a
condition requiring repair or replacement?
ÐVerify repairGo to Step 9
9Start the engine and note the idle quality.
Is a low or unsteady idle being experienced?
ÐGo to Step 10Go to Step 11
101. Turn the ignition off and physically inspect the
throttle body bore, throttle plate, and IAC passages
for coking and foreign objects.
2. If a problem was found, repair as necessary.
Did your inspection reveal a condition requiring repair?
ÐVerify repairGo to Step 11
111. Disconnect the vacuum hose from the fuel pressure
regulator and inspect the hose for the presence of
fuel.
2. If fuel is present in the vacuum hose, replace the
fuel pressure regulator (refer to
Fuel Metering
System
).
Did the fuel pressure regulator require replacement?
ÐVerify repairGo to Step 12
121. Ignition ªONº, engine ªOFFº.
2. Monitor the TP Angle display on the Tech 2 while
slowly depressing the accelerator pedal.
Does the TP Angle display increase steadily and
evenly from minimum value at closed throttle to
maximum value at wide-open throttle?
Minimum 8%
Maximum
92%
Go to Step 13Go to Step 21
131. Disconnect the MAF sensor electrical connector.
2. Operate the vehicle in ªclosed loopº while
monitoring the ªBANK 2 L.T. FUEL TRIMº and
ªBANK 2 S.T. FUEL TRIMº display on the Tech 2.
Did both values change to near the specified value?
0%Go to Step 22Go to Step 14
141. Perform the ªFuel System Pressure Testº.
2. If Fuel System Pressure Test isolates a problem,
repair as necessary (refer to
Engine Fuel or Fuel
Metering System
).
Did the Fuel System Pressure Test isolate a condition
requiring repair?
ÐVerify repairGo to Step 15
151. Ignition ªONº, engine ªOFFº.
2. Connect a test light between the harness connector
terminals of canister purge solenoid.
Is the test light on?
ÐGo to Step 16Go to Step 19
16Check for short to ground in the wire (YEL/RED)
between the canister purge solenoid and PCM terminal
S-48.
Was there a short to ground?
ÐGo to Step 17Go to Step 18

6E±256
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0300 Engine Misfire Detected
Circuit Description
Misfire is monitored as a function of the combustion
quality (CQ) signals generated from the ION Sensing
Module. Combustion signals represent the degree of
combustion in each cylinder. Misfire is detected when the
combustion signal is below a predetermined value.
This DTC P0300 will determine if a multiple cylinder
misfire is occurring by monitoring the Combustion
Quality.
Conditions for Setting the DTC

None of the following DTCs occur: TP sensor, MAF
sensor, VSS, ECT sensor.

The engine speed is between 600 and 6250 RPM.

The system voltage is between 11 and 16 volts.

The engine temperature sensor (ECT) indicates an
engine temperature between ±7
C (20
F) and 110
C
(230
F).

Throttle angle is steady and throttle changes less than
2% per 125 milliseconds.
Action Taken When the DTC Sets

The PCM will ON the MIL after second trip with
detected the fault.

If the misfire is severe enough to cause possible
catalyst damage, the PCM will flash the MIL for as long
as the misfire remains at catalyst damaging levels.

The PCM will disable the TCC operation.

The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in the
Failure Records data.
Conditions for Clearing the MIL/DTC

The PCM will turn the MIL ªOFFº on the third
consecutive trip cycle in which the diagnostic has been
run and the fault condition is no longer present.

A history DTC P0300 will clear after 40 consecutive
warm-up cycles occur without a fault.

DTC P0300 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.
Diagnostic Aids
The Tech 2 display ªMisfire Cur. #1 through #6º can be
useful to determine whether the misfire is isolated to a
single cylinder.
Damaged or faulty ignition coil ± Check for cracks or
other damage.

Substitute a known good coil ± Swap the ignition coils
and retest. If the misfire follows the coil, replace the
ignition coil.
If the misfire is random, check for the following conditions:

System grounds ± Ensure all connections are clean
and properly tightened.

MAF ± A mass air flow (MAF) sensor output that
causes the PCM to sense a lower than normal air flow
will cause a lean condition.

Air induction system ± Air leaks into the induction
system which bypass the MAF sensor will cause a lean
condition. Check for disconnected or damaged
vacuum hoses, incorrectly installed or faulty PCV
valve, or for vacuum leaks at the throttle body, EGR
valve, and intake manifold mounting surfaces.

Fuel pressure ± Perform a fuel system pressure test.
A faulty fuel pump, plugged filter, or faulty fuel system
pressure regulator will contribute to a lean condition.

Injector(s) ± Perform an injector coil/balance test to
locate faulty injector(s) contributing to a lean or
flooding condition. In addition to the above test, check
the condition of the injector O-rings.

EGR ± Check for a leaking valve, adapter, or feed pipes
which will contribute to a lean condition or excessive
EGR flow.

Fuel quality ± Using fuel with the wrong octane rating
for the vehicle may cause driveability problems.
Although alcohol-enhanced fuels may raise the octane
rating, the fuel's ability to turn into vapor in cold
temperatures deteriorates. This may affect the cold
driveability of the engine. The Reid Vapor Pressure of
the fuel can also create problems in the fuel system,
especially during the spring and fall when changes by
the refineries may not coincide with changes in the
weather.

Vehicle marshalling ± The transportation of new
vehicles from the assembly plant to the dealership can
involve as many as 60 key cycles within 2 to 3 miles of
driving. This type of operation contributes to the fuel
fouling of the spark plugs and will turn on the MIL with
a P0300 Misfire DTC.
Reviewing the Failure Records vehicle mileage since the
diagnostic test last failed may help determine how often
the condition that caused the DTC to be set occurs. This
may assist in diagnosing the condition.

6E±257
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0300 ± Engine Misfire Detected

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Start the engine. Run the engine at idle.
2. Review and record the Tech 2 Freeze Frame data.
3. Operate the vehicle to duplicate the conditions
present when the DTC was set (as defined by the
Freeze Frame data).
4. Monitor the Tech 2 ªMisfire Cur. #º display for each
cylinder.
Is ªMisfire Cur. #º display increasing for any cylinder
(indicating a misfire currently occurring)?
ÐGo to Step 3
Refer to
Diagnostic
Aids
31. Visually and physically inspect the vacuum hoses
for splits, kinks, and improper connections.
2. If a problem is found, repair or replace the vacuum
hoses as necessary.
Did your inspection reveal a problem?
ÐVerify repair Go to Step 4
41. Visually and physically inspect the following areas
for vacuum leaks:

The intake manifold

The injector O-rings

The EGR adapter

The EGR feed pipes

ION Sensing Module
2. If a problem is found, repair the vacuum leak as
necessary.
Did your inspection reveal a vacuum leak?
ÐVerify repairGo to Step 5
51. Visually and physically inspect the crankcase
ventilation valve for improper installation or
damaged grommet.
2. If a problem is found, repair as necessary (refer to
Crankcase Ventilation System).
Did your inspection reveal a problem?
ÐVerify repairGo to Step 6
61. Inspect the MAF sensor inlet screen for damage or
for the presence of foreign objects that may partially
block the air flow sample through the MAF sensor.
2. If a problem is found, repair or replace the MAF
sensor as necessary.
Did your inspection of the MAF sensor reveal a
condition requiring repair or replacement?
ÐVerify repairGo to Step 7
71. Remove the EGR valve and visually/physically
inspect the valve to ensure that the pintle is not
sticking partially open. Also, inspect the EGR valve
pintle and seat for carbon deposits or burrs that may
interfere with the pintle closing completely.
2. If a problem is found, clean the EGR valve pintle and
seat or replace the EGR valve as necessary.
Did your inspection reveal a problem?
ÐVerify repairGo to Step 8

6E±258
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0300 ± Engine Misfire Detected

 
StepNo Ye s Value(s) Action
81. Install a spark tester at the spark plug end of the
ignition coil for a cylinder that indicated a misfire.
2. Crank the engine while observing the spark tester.
A crisp, blue spark should be observed.
Is adequate spark present?
ÐGo to Step 14Go to Step 9
91. Remove and visually/physically inspect the ignition
coil(s) associated with the cylinders that were
indicated as misfiring. Ensure that the coil(s) are
free of cracks.
2. If a problem is found, replace the damaged ignition
coil(s) as necessary.
Did any ignition coils require replacement?
ÐVerify repairGo to Step 10
101. Remove the spark plugs from the cylinders that
were indicated as misfiring.
2. Visually inspect the spark plug electrodes.
Does your inspection reveal any spark plugs exhibiting
excessive fouling?
Ð
Go to Engine
Mechanical
Diagnosis
Go to Step 11
111. Visually inspect the spark plug insulators for cracks,
carbon tracking, or other damage.
2. If a problem is found, replace the faulty spark
plug(s) as necessary.
Did your inspection reveal a problem?
ÐVerify repairGo to Step 12
121. Disconnect the MAF sensor electrical connector.
2. Operate the vehicle in ªclosed loopº while
monitoring the ªBANK 1 L.T. FUEL TRIMº and
ªBANK 1 S.T. FUEL TRIMº display on the Tech 2.
Do both values decrease below the specified values?ºBANK 1 L.T.
FUEL TRIMº
below +20%;
ªBANK 1 S.T.
FUEL TRIMº
below +50%
Go to Step 13
Replace the
ignition coil of
the affected
cylinder
13Replace the ignition coil control module.
Is the action complete?
ÐVerify repairÐ
141. Visually and physically inspect the PCM injector
grounds, power grounds and sensor grounds to
ensure that they are clean, tight and in their proper
locations.
2. If a problem is found, correct the faulty ground
condition as necessary.
Did your inspection reveal a poor ground?
ÐVerify repair Go to Step 15
151. Perform the ªFuel System Pressure Testº
procedure.
2. If a problem is found, repair as necessary (refer to
Engine Fuel or Fuel Metering System).
Was a fuel system problem found?
ÐVerify repairGo to Step 16
161. Check the fuel for excessive water, alcohol, or other
contaminants (refer to
Diagnosis in Engine Fuel for
procedure).
2. If a problem is found, correct the contaminated fuel
condition as necessary.
Was the fuel contaminated?
ÐVerify repairGo to Step 17

6E±273
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
If the harness appears to be OK, observe the Knock
Present, Knock Sensor Noise Channel display on
the Tech 2 while moving connectors and wiring
harnesses related to the sensor.
A change in the display will indicate the location of
the fault.If DTC P0325 cannot be duplicated, the information
included in the Failure Records data can be useful in
determined vehicle mileage since the DTC was last
set.
If it is determined that the DTC occurs intermittently,
performing the DTC P0325 Diagnostic Chart may
isolate the cause of the fault.
DTC P0325 - ION Sensing Module Knock Intensity Circuit Fault

StepActionValue(s)Ye sNo
1Was the ªOn-Board (OBD) System Checkº performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Ignition ªONº, engine ªOFFº.
2. Review and record Tech 2 Failure Records data.
3. Operate the vehicle within Failure Records
conditions as noted.
4. Using a Tech 2, monitor ªDTCº info for DTC P0325.
Does the Tech 2 indicate DTC P0325 failed this
ignition?
ÐGo to Step 3
Refer to
Diagnostic
Aids
31. Ignition ªOFFº.
2. Disconnect the ION sensing module.
3. Disconnect the PCM.
Is the action complete?
ÐGo to Step 4Ð
4Check the ION sensing harness between the PCM
(F68) and ION sensing module circuit (RED Wire) at
the KI line harness connector.
Was a problem found?
ÐVerify repairGo to Step 5
51. Disconnect the ignition coil.
Is the action complete?
ÐGo to Step 6Ð
6Check the ION sensing harness for open or short circuit
between the ignition coil and ION sensing module
circuit at the harness connector.
Was a problem found?
ÐVerify repairGo to Step 7
7Check the following items;
1. Ignition coil and ignition coil circuit.
2. Ignition coil ground circuit for a poor connection.
3. If a problem is found, repair wiring harness as
necessary.
Was a problem found?
ÐVerify repairGo to Step 8
8Replace the Ignition coil.
Is the action complete?
ÐVerify repairGo to Step 9
9Check the following items;
1. ION sensing module ground circuit for a poor
connection.
2. If a problem is found, repair wiring harness as
necessary.
Was a problem found?
ÐGo to Step 10Go to Step 11
10Repair wiring harness.
Is the action complete?
ÐVerify repairGo to Step 11