2002 ISUZU AXIOM ECU

6E±304
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0404 EGR Open Stuck
060R200050
Circuit Description
The powertrain control module (PCM) monitors the EGR
valve pintle position input to ensure that the valve
responds properly to commands from the PCM, and to
detect a fault if pintle position is different from
commanded position. If the PCM detects a pintle position
signal indicates more than 15 points different between
current and commanded and more than 15 seconds, the
PCM will set DTC P0404.
Conditions for Setting the DTC

The engine is running.

Ignition voltage is between 11 and 16 volts.

Intake Air Temp is more than 3
C (37.4
F).

Desire EGR position is less than 3%.

The difference between desired EGR and current EGR
is less than 3%.

Difference EGR pintle position between current and
commanded position becomes more than 15% and
last more than 15 seconds, and this condition meets
three times in a trip. Then it trigger, the PCM lights on.
Action Taken When the DTC Sets

The PCM will ON the MIL after second trip with
detected the fault.
The PCM will store conditions which were present
when the DTC was set as Freeze Frame and in Failure
Records data.
Conditions for Clearing the MIL/DTC

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

A history DTC P0404 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0404 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:

Excessive carbon deposit on EGR valve shaft may
cause EGR stuck open or unsmooth operation. Those
carbon deposit may occur by unusual port operation.
Clean up carbon may make smooth function of EGR
valve.

Poor connection or damaged harness ± Inspect the
wiring harness for damage. If the harness appears to
be OK, observe the EGR actual position display on the
Tech 2 while moving connectors and wiring harnesses
related to EGR valve. A change in the display will
indicate the location of the fault.

6E±306
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0405 EGR Low Voltage
060R200050
Circuit Description
The powertrain control module (PCM) monitors the EGR
valve pintle position input to ensure that the valve
responds properly to command from the PCM. If current
pintle position voltage indicates less than 0.1 V and last
more than 10 seconds, then the PCM will set DTC P0405.
Conditions for Setting the DTC

Ignition voltage is between 11 and 16 volts.

Intake Air Temp is more than 3
C (37.4
F).

EGR pintle position is less than 2% and last more than
10 sec. Action taken when the DTC sets.
Action Taken When the DTC Sets

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

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

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

A history DTC P0402 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0405 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 or damaged harness ± Inspect the
wiring harness for damage. If the harness appears to
be OK, observe the EGR actual position display on the
Tech 2 while moving connectors and wiring harnesses
related to EGR valve. A change in the display will
indicate the location of the fault.

6E±309
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0406 EGR High Voltage
060R200050
Circuit Description
The powertrain control module (PCM) monitors the EGR
valve pintle position input to ensure that the valve
responds properly to command from the PCM. If current
pintle position voltage indicates more than 4.8 V and last
more than 10 seconds, then the PCM will set DTC P0406.
Conditions for Setting the DTC

Ignition voltage is between 11 and 16 volts.

Intake Air temp is more than 3
C (37.4
F).

EGR pintle position is more than 99% and last more
than 10 sec.
Action Taken When the DTC Sets

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

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

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

A history DTC P0402 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0404 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 or damaged harness ± Inspect the
wiring harness for damage. If the harness appears to
be OK, observe the EGR actual position display on the
Tech 2 while moving connectors and wiring harnesses
related to EGR valve. A change in the display will
indicate the location of the fault.

6E±312
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0420 TWC System Low Efficiency Bank 1
T321075
Circuit Description
To control emissions of hydrocarbons (HC), carbon
monoxide (CO), and oxides of nitrogen (NOx), a
three-way catalyst (TWC) is used. The catalyst promotes
a chemical reaction which oxidizes the HC and CO
present in the exhaust gas, converting them into
harmless water vapor and carbon dioxide. The catalyst
also reduces NOx, converting it to nitrogen. The
powertrain control module (PCM) has the ability to
monitor this process using the Bank 1 HO2S 1 and the
Bank 1 HO2S 2 heated oxygen sensors. The Bank 1
HO2S 1 sensor produces an output signal which indicates
the amount of oxygen present in the exhaust gas entering
the three-way catalytic converter. The Bank 1 HO2S 2
sensor produces an output signal which indicates the
oxygen storage capacity of the catalyst; this in turn
indicates the catalyst's ability to convert exhaust gases
efficiently. If the catalyst is operating efficiently, the Bank
1 HO2S 1 signal will be far more active than that produced
by the Bank 1 HO2S 2 sensor. If the PCM detects a level
of Bank 1 HO2S 2 activity that indicates the catalyst is no
longer operating efficiently, DTC P0420 will be set.
Conditions for Setting the DTC

No related DTCs.

The engine is operating in ªclosed loopº,

Engine air load is below 99%.

Engine coolant temperature is between 70
C (158
F)
and 120
C (248
F).

Mass air flow is between 2.5 g/second and 10
g/second.

Engine speed is below 200 RPM.

Catalyst temperature is above 350
C (662
F).

The PCM determines that the catalyst's oxygen
storage capacity is below the acceptable threshold.

Intake Air Temperature is between ±10
C (14
F) and
70
C (158
F).

Throttle angle is less than 1.5%.
Barometric Pressure is more than 72 kPa.
Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.

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 during which the diagnostic has
been run and the fault condition is no longer present.

A history DTC P0420 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0420 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
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.
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.
The ªTWC Monitor Test Counterº displayed on the Tech 2
may be used to monitor the progress of the TWC
diagnostic. To complete the TWC diagnostic with a good
catalyst, the counter must be allowed to increment to 49
samples and roll over to 0 at least twice. A failed catalyst

6E±314
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0420 ± TWC System Low Efficiency Bank 1

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Are any other DTCs set (such as P0140)?
Ð
Diagnose
other DTC(s)
first
Go to Step 3
31. Visually and physically inspect the three-way
catalytic converter for damage. Check for the
following:

dents

severe discoloration caused by excessive
temperatures

holes

internal rattle caused by damaged catalyst
2. Also, ensure that the three-way catalytic converter
is a proper original equipment manufacturer part.
Did your inspection reveal a problem?
ÐGo to Step 6Go to Step 4
41. Visually and physically inspect the exhaust system
between the three-way catalytic converter and the
rear converter flange for leaks, damage, and loose
or missing hardware.
2. If a problem is found, repair as necessary.
Did your inspection reveal a problem?
Ð
Go to Step 7
to verify
repair
Go to Step 5
51. Visually and physically inspect the Bank 1 HO2S 2.
2. Ensure that the Bank 1 HO2S 2 is secure and that
the pigtail and wiring harness is not contacting the
exhaust pipe or is not otherwise damaged.
3. If a problem is found, repair as necessary.
Did your inspection reveal a problem?
Ð
Go to Step 7
to verify
repair
Go to Step 6
6Replace the three-way catalytic converter.
NOTE: Check for conditions which may cause catalyst
damage (refer to
Diagnostic Aids).
Is the action complete?
Ð
Go to Step 7
to verify
repair
Ð
71. Review and record the Tech 2 Failure Records data.
2. Clear DTC P0420.
3. Start the engine and allow it to warm up until the
engine coolant temperature monitored on the Tech
2 is above the specified value.
4. Run the engine to maintain the specified mass air
flow range for at least 2 minutes.
5. Operate the vehicle to maintain DTC P0420 test
conditions (refer to
DTC Test Description in
Diagnostic Support for detailed instructions).
6. Using a Tech 2, monitor ªDTCº info for DTC P0420
until the DTC P0420 test runs.
7. Note the test result.
Does the Tech 2 indicate DTC P0420 passed this
ignition?
Engine
coolant temp:
greater than
60
C
(140
F).
Mass air flow:
between 8
g/second and
50 g/second
Complete
repair. If a
driveability
symptom still
exists, refer
to
Symptoms.
Go to the
Diagnostic
Aids

6E±315
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC) P0430 TWC System Low Efficiency Bank 2
T321075
Circuit Description
To control emissions of hydrocarbons (HC), carbon
monoxide (CO), and oxides of nitrogen (NOx), a
three-way catalyst (TWC) is used. The catalyst promotes
a chemical reaction which oxidizes the HC and CO
present in the exhaust gas, converting them into
harmless water vapor and carbon dioxide. The catalyst
also reduces NOx, converting it to nitrogen. The
powertrain control module (PCM) has the ability to
monitor this process using the Bank 2 HO2S 1 and the
Bank 2 HO2S 2 heated oxygen sensors. The Bank 2
HO2S 1 sensor produces an output signal which indicates
the amount of oxygen present in the exhaust gas entering
the three-way catalytic converter. The Bank 2 HO2S 2
sensor produces an output signal which indicates the
oxygen storage capacity of the catalyst; this in turn
indicates the catalyst's ability to convert exhaust gases
efficiently. If the catalyst is operating efficiently, the Bank
2 HO2S 1 signal will be far more active than that produced
by the Bank 2 HO2S 2 sensor. If the PCM detects a level
of Bank 2 HO2S 2 activity that indicates the catalyst is no
longer operating efficiently, DTC P0430 will be set.
Conditions for Setting the DTC

No related DTCs.

The engine is operating in ªclosed loopº.

Engine air load is below 99%.

Engine coolant temperature is between 70
C (158
F)
and 120
C (248
F).
Mass air flow is between 2.5 g/second and 10
g/second.

Change in engine load is below 8%.

Engine speed is below 200 RPM.

Catalyst temperature is above 350
C (662
F).

The PCM determines that the catalyst's oxygen
storage capacity is below the acceptable threshold.

Intake air temperature is between ±20
C (4
F) and
70
C (158
F).

Throttle angle is less than 1.5%.

Barometric Pressure is more than 72 kPa.
Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator lamp
(MIL) the first time the fault is detected.

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 during which the diagnostic has
been run and the fault condition is no longer present.

A history DTC P0430 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0430 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.

6E±317
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0430 ± TWC System Low Efficiency 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 other DTCs set (such as P0160)?
Ð
Diagnose
other DTC(s)
first
Go to Step 3
31. Visually and physically inspect the three-way
catalytic converter for damage. Check for the
following:

dents

severe discoloration caused by excessive
temperatures

holes

internal rattle caused by damaged catalyst
2. Also, ensure that the three-way catalytic converter
is a proper original equipment manufacturer part.
Did your inspection reveal a problem?
ÐGo to Step 6Go to Step 4
41. Visually and physically inspect the exhaust system
between the three-way catalytic converter and the
rear converter flange for leaks, damage, and loose
or missing hardware.
2. If a problem is found, repair as necessary.
Did your inspection reveal a problem?
Ð
Go to Step 7
to verify
repair
Go to Step 5
51. Visually and physically inspect the Bank 2 HO2S 2.
2. Ensure that the Bank 2 HO2S 2 is secure and that
the pigtail and wiring harness is not contacting the
exhaust pipe or is not otherwise damaged.
3. If a problem is found, repair as necessary.
Did your inspection reveal a problem?
Ð
Go to Step 7
to verify
repair
Go to Step 6
6Replace the three-way catalytic converter.
NOTE: Check for conditions which may cause catalyst
damage (refer to
Diagnostic Aids).
Is the action complete?
Ð
Go to Step 7
to verify
repair
Ð
71. Review and record the Tech 2 Failure Records data.
2. Clear DTC P0430.
3. Start the engine and allow it to warm up until the
engine coolant temperature monitored on the Tech
2 is above the specified value.
4. Run the engine to maintain the specified mass air
flow range for at least 6 minutes.
5. Operate the vehicle to maintain DTC P0430 test
conditions (refer to
DTC Test Description in
Diagnostic Support for detailed instructions).
6. Using a Tech 2, monitor ªDTCº info for DTC P0430
until the DTC P0430 test runs.
7. Note the test result.
Does the Tech 2 indicate DTC P0430 passed this
ignition?
Engine
coolant temp:
greater than
70
C
(158
F).
Mass air flow:
between 2.5
g/second and
10 g/second
Complete
repair. If a
driveability
symptom still
exists, refer
to
Symptoms.
Go to the
Diagnostic
Aids

6E±319
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Engine speed is less than 1200 RPM.

Above conditions are present for 60 to 180 seconds.
Action Taken When the DTC Sets

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

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

The PCM will turn the MIL ªOFFº when the diagnostic
has been run and the fault condition is no longer
present.

A history DTC P0440 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0440 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:

Cracked or punctured EVAP canister.

Damaged or disconnected source vacuum line, EVAP
purge line, vent hose or fuel tank vapor line.

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 to the
EVAP canister vent solenoid, EVAP canister purge
solenoid and the fuel tank pressure sensor for an
intermittent open or short circuit.

Kinked, pinched, or plugged vacuum source, EVAP
purge, or fuel tank vapor line±Verify that the lines are
not restricted.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.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
2. If an EVAP canister vent solenoid or an EVAP
canister purge solenoid electrical fault is present,
the purge system will not operate correctly.
Repairing the electrical fault will very likely correct
the condition that set DTC P0440.
3. Checks the fuel tank pressure sensor at ambient
pressure.
4. Determines whether or not the EVAP system can be
sealed sufficiently to be pressurized. If not, the
large leak must be located and corrected before
continuing with diagnosis.
5. Verifies that the fuel tank pressure sensor accurately
reacts to EVAP system pressure changes.
8. Checks for a blocked EVAP canister purge solenoid.
The PCM commands the EVAP canister purge
solenoid ªOFFº (open) and the vent solenoid ªONº
(closed) with the Tech 2 ªSystem Perfº, EVAP
output control function activated. Any pressure in
the system should be released through the EVAP
canister purge solenoid within a few seconds when
ªSystem Perfº, is activated.
9. Ensures that sufficient source vacuum is present at
the EVAP canister purge solenoid.
DTC P0440 ± EVAP System

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
2Is DTC P0452 or P0453 also set?
Ð
Go to other
DTC first
Go to Step 3
31. Ignition ªOFFº.
2. Remove the fuel cap.
3. Ignition ªONº.
4. Observe ªFuel Tank Pressureº on the Tech 2.
Does the Tech 2 indicate ªFuel Tank Pressureº at the
specified value?
1.51 VGo to Step 4
Go to DTC
P0452
or
DTC P0453
41. Replace the fuel cap.
2. Engine is running.
3. Observe ªFuel Tank Vacuumº on the Tech 2.
Does Tech 2 indicate ªFuel Tank Vacuumº at the
specified value?
1.47±1.51 VGo to Step 7Go to Step 6