heated ISUZU AXIOM 2002 Service User Guide

6E±57
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Primary System-Based Diagnostic
Primary System-Based Diagnostic
There are primary system-based diagnostics which
evaluate system operation and its effect on vehicle
emissions. The primary system-based diagnostics are
listed below with a brief description of the diagnostic
function:
Oxygen Sensor Diagnosis
The fuel control heated oxygen sensors (Bank 1 HO2S 1
and Bank 2 HO2S 1) are diagnosed for the following
conditions:

Heater performance (time to activity on cold start)

Slow response

Response time (time to switch R/L or L/R)

Inactive signal (output steady at bias voltage ±
approx. 450 mV)

Signal fixed high

Signal fixed low
The catalyst monitor heated oxygen sensors (Bank 1
HO2S 2 and Bank 2 HO2S 2) are diagnosed for the
following conditions:

Heater performance (time to activity on cold start).

Signal fixed low during steady state conditions or
power enrichment (hard acceleration when a rich
mixture should be indicated).

Signal fixed high during steady state conditions or
deceleration mode (deceleration when a lean mixture
should be indicated).

Inactive sensor (output steady at approx. 438 mV).
If the oxygen sensor pigtail wiring, connector or terminal
are damaged, the entire oxygen sensor assembly must
be replaced. DO NOT attempt to repair the wiring,
connector or terminals. In order for the sensor to function
properly, it must have clean reference air provided to it.
This clean air reference is obtained by way of the oxygen
sensor wire(s). Any attempt to repair the wires, connector
or terminals could result in the obstruction of the
reference air and degrade oxygen sensor performance.
Refer to
On-Vehicle Service, Heated Oxygen Sensors in
this section.
Fuel Control Heated Oxygen Sensor
The main function of the fuel control heated oxygen
sensors is to provide the control module with exhaust
stream oxygen content information to allow proper fueling
and maintain emissions within mandated levels. After it
reaches operating temperature, the sensor will generate
a voltage, inversely proportional to the amount of oxygen
present in the exhaust gases. The control module uses
the signal voltage from the fuel control heated oxygen
sensors while in closed loop to adjust fuel injector pulse
width. While in closed loop, the PCM can adjust fuel
delivery to maintain an air/fuel ratio which allows the best
combination of emission control and driveability. The fuel
control heated oxygen sensors are also used to
determine catalyst efficiency.
HO2S Heater
Heated oxygen sensors are used to minimize the amount
of time required for closed loop fuel control to begin
operation and to allow accurate catalyst monitoring. The
oxygen sensor heater greatly decreases the amount of
time required for fuel control sensors (Bank 1 HO2S 1 and
Bank2 HO2S 1) to become active. Oxygen sensor
heaters are required by catalyst monitor and sensor
(Bank 1 HO2S 2 and Bank 2 HO2S 2) to maintain a
sufficiently high temperature which allows accurate
exhaust oxygen content readings further away from the
engine.
Catalyst Monitor Heated Oxygen Sensors
and Diagnostic Operation
TS24067
To control emissions of hydrocarbons (HC), carbon
monoxide (CO), and oxides of nitrogen (NOx), a
three-way catalytic converter is used. The catalyst within
the converter 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 PCM has the ability to monitor this process
using the pre-catalyst and post-catalyst heated oxygen
sensors. The pre-catalyst sensor produces an output
signal which indicates the amount of oxygen present in
the exhaust gas entering the three-way catalytic
converter. The post-catalyst 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 pre-catalyst signal will be far
more active than that produced by the post-catalyst
sensor.
In addition to catalyst monitoring, the heated oxygen
sensors have a limited role in controlling fuel delivery. If
the sensor signal indicates a high or low oxygen content
for an extended period of time while in closed loop, the
PCM will adjust the fuel delivery slightly to compensate.

6E±80
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Tech 2
ParameterRefer To Typical Data
Values
(2500 RPM) Typical Data
Values (IDLE) Units Displayed Data List
EGR Duty
CycleEnginePercent0%0%General Description and
Operation, Linear EGR
Operation and Results of
Incorrect Operation
EGR
FeedbackEngineVolts0.45-0.800.45-0.80Ð
EGR
NormalizedEnginePercent0%0%Ð
Engine LoadEnginePercent2.0% - 5.5%8.0% - 16.0%General Description and
Operation, Mass Air Flow
(MAF) Sensor
Time From
StartEngineSecVaries. Resets
at each engine
start.Varies. Resets
at each engine
start.
Ð
Engine SpeedEngineRPMWithin ±50 to
+100 of
ªDesired IdleºActual engine
speed
Ð
EVAP Purge
SolenoidEnginePercent0%0%Diagnosis, EVAP
Emission Canister Purge
Valve Check
EVAP Vent
ValveEngineOn/OffOffOffDiagnosis, EVAP Canister
Purge Solenoid and
EVAP Vacuum Switch
and Visual Check; DTCs:
P1441, P1442
Fuel System
StatusEngineOpen
Loop/Closed
LoopClosed LoopClosed LoopGeneral Description
Fuel LevelEnginePercentÐÐEngine Fuel
Fuel Level
SensorEngineVoltsÐÐEngine Fuel
Fuel Tank
(Vapor)EngineVolts1.02 ± 1.861.02 ± 2.57General Description and
Operation
Pressure
Sensorin. H2OÐÐ
Fuel PumpEngineOn/OffOnOnEngine Fuel
HO2S Bank 1
Sen.1
(millivolts)O2
Sensor
DataMillivolts50-950
changing
quickly50-950, always
changing
quicklyGeneral Description and
Operation, Fuel control
HO2S
HO2S Bank 1
Sen.2
(millivolts)
(Auto Trans)O2
Sensor
DataMillivolts200-700
changing slowly250-650
changing slowlyGeneral Description and
Operation, Fuel Metering
System
HO2S Bank 1
Sen.2
(millivolts)
(Manual
Trans)O2
Sensor
DataMillivolts50-950
changing
quickly50-950
changing
quicklyGeneral Description and
Operation, Fuel Metering
System
HO2S Bank 1
Sen.3
(millivolts)
(Manual
Trans)O2
Sensor
DataMillivolts200-700
changing slowly250-650
changing slowlyGeneral Description and
Operation, Catalyst
Monitor Heated Oxygen
Sensor (Manual Trans)

6E±81
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Tech 2
ParameterRefer To Typical Data
Values
(2500 RPM) Typical Data
Values (IDLE) Units Displayed Data List
HO2S Bank 2
Sen.1
(millivolts)O2
Sensor
DataMillivolts50-950
changing
quickly50-950
changing
quicklyGeneral Description and
Operation, Fuel Control
HO2S
HO2S Bank 2
Sen.2
(millivolts)
(Auto trans)O2
Sensor
DataMillivolts200-700
changing slowly250-650
changing slowlyGeneral Description and
Operation, Fuel Metering
System
HO2S Bank 1
Sen.1
(ready/not
ready)O2
Sensor
DataReady
Yes/NoReady
Ye sReady
Ye sGeneral Description and
Operation, Fuel Control
HO2S; DTC: P0135
HO2S Bank 2
Sen.1
(ready/not
ready)O2
Sensor
DataReady
Yes/NoReady
Ye sReady
Ye sGeneral Description and
Operation, Fuel Control
HO2S
HO2S
Warm-Up Time
Bank 1 Sen.1O2
Sensor
DataSeconds25-4525-45General Description and
Operation, Fuel Control
HO2S
HO2S
Warm-Up Time
Bank 1 Sen.2O2
Sensor
DataSeconds60-10060-100General Description and
Operation, Fuel Control
HO2S
HO2S
Warm-Up Time
Bank 2 Sen.1O2
Sensor
DataSeconds25-4525-45General Description and
Operation, Fuel Control
HO2S
HO2S
Warm-Up Time
Bank 2 Sen.2O2
Sensor
DataSeconds60-10060-100General Description and
Operation, Catalyst
Monitor Heated Oxygen
Sensor (Auto Trans)
IAT (Intake Air
Temp)EngineDegrees C,
Degrees F0-100
C,
depends on
underhood
temperature0-80
C,
depends on
underhood
temperatureGeneral Description and
Operation, Intake Air
Temperature (IAT) Sensor
Illumination
SwitchEngineClosed 0V/Open
12VClosed 0VClosed 0VRefer to Section 8
Ignition
VoltageEngineVolts12.8-14.112.8-14.1General Description and
Operation, Electronic
Ignition System
Inj. Pulse Bank
1EngineMilliseconds2.0-4.02.5-4.0General Description, Fuel
Metering, Fuel Injector
Inj. Pulse Bank
2EngineMilliseconds2.0-4.02.5-4.0General Description, Fuel
Metering, Fuel Injector
Knock PresentEngineNo/YesNoNoGeneral Description and
ION Sensing Module
Knock SignalEnginePercent1~41~4General Description and
ION Sensing Module
Knock Sensor
RetardEngine
CA00General Description and
ION Sensing Module
Knock CounterEngineCountsÐÐGeneral Description
Long Term FT
Bank 1 (Long
Term Fuel
Trim)MisfireCounts and
Percentage100 to 150
counts, ±22%
to +17%100 to 150
counts, ±22%
to +17%Diagnosis, Fuel Trim
System Monitor; DTCs:
P0171, P0172

6E±161
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P0125 ECT Excessive Time to Closed Loop Fuel Control
060R200053
Circuit Description
To provide the best possible combination of driveability,
fuel economy, and emission control, a ªclosed loopº
air/fuel metering system is used. When the vehicle is first
started, the powertrain control module (PCM) controls
fuel delivery in ªopen loopº, ignoring the heated oxygen
sensor (HO2S) signals and calculating air/fuel ratio based
on inputs from the engine coolant temperature, throttle
position, and mass air flow sensors. The PCM will begin
using the Bank 1 HO2S 1 and Bank 2 HO2S 1 signals for
controlling fuel delivery under ªclosed loopº conditions
when the following conditions have been met:

The HO2S output signals are varying, indicating that
the sensors are hot enough to operate properly.

The engine coolant temperature sensor indicates
coolant temperature above 50
C (122
F).

Time since start-up is at least 16 seconds for a warm
engine or 23 seconds for a cold engine.
Conditions for Setting the DTC

No active IAT, MAF or ECT DTC(s) are present.

Engine is running.

Vehicle speed is greater than 5 mph (8 km/h) .

Intake air temperature is greater than ±10
C (14
F)
0
C (32
F).

Start±up engine coolant temperature is between
±10
C (±14
F) and 28
C (82
F).
For a warm engine (intake air temperature is greater
than 10
C/50
F), engine coolant temperature
sufficient to allow ªclosed loopº operation
(50
C/122
F) is not achieved within 2 minutes of
start-up. For a cold engine (intake air temperature
between (±7
C and 10
C), engine coolant
temperature sufficient to allow ªclosed loopº operation
(50
C/122
F) is not achieved within 10 minutes of
start-up.

The above condition fails 20 consecutive times.
Action Taken When the DTC Sets

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

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 P0125 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0125 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.

6E±166
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P0131 HO2S Circuit Low Voltage Bank 1 Sensor 1
060R200054
Circuit Description
The powertrain control module (PCM) supplies a bias
voltage of about 450 mV between the heated oxygen
sensor (HO2S) signal high and signal low circuits. When
measured with a 10 megaohm digital voltmeter, this may
display as low as 350 mV. The oxygen sensor varies the
voltage within a range of about 1000 mV when the
exhaust is rich, down through about 10 mV when exhaust
is lean. The PCM constantly monitors the HO2S signal
during ªclosed loopº operation and compensates for a rich
or lean condition by decreasing or increasing injector
pulse width as necessary. If the Bank 1 HO2S 1 voltage
remains excessively low for an extended period of time,
DTC P0131 will be set.
Conditions for Setting the DTC

No related DTCs.

Vehicle is operating in ªclosed loopº.

Engine coolant temperature is above 60
C (140
F).

ªClosed loopº commanded air/fuel ratio is between
14.5 and 14.8.

Bank 1 HO2S 1 signal voltage remains below 22 mV
during normal ªclosed loopº operation for a total of 77
seconds over a 90-second period of time.
Action Taken When the DTC Sets

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

ªOpen loopº fuel control will be in effect.
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 P0131 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0131 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:

Heated oxygen sensor wiring ± The sensor pigtail may
be routed incorrectly and contacting the exhaust
system.

Poor PCM to engine block grounds.

Fuel pressure ± The system will go lean if pressure is
too low. The PCM can compensate for some
decrease. However, If fuel pressure is too low, a DTC
P0131 may be set. Refer to
Fuel System Diagnosis.

Lean injector(s) ± Perform ªInjector Balance Testº.

Vacuum leaks ± Check for disconnected or damaged
vacuum hoses and for vacuum leaks at the intake
manifold, throttle body, EGR system, and PCV system.

6E±169
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P0132 HO2S Circuit High Voltage Bank 1 Sensor 1
060R200054
Circuit Description
The powertrain control module (PCM) supplies a bias
voltage of about 450 mV between the heated oxygen
sensor (HO2S) signal and low circuits. When measured
with a 10 megaohm digital voltmeter, this may display as
low as 320 mV. The oxygen sensor varies the voltage
within a range of about 1000 mV when exhaust is rich,
down through about 10 mV when exhaust is lean. The
PCM constantly monitors the HO2S signal during ªclosed
loopº operation and compensates for a rich or lean
condition by decreasing or increasing injector pulse width
as necessary. If the Bank 1 HO2S 1 voltage remains
excessively high for an extended period of time, DTC
P0132 will be set.
Conditions for Setting the DTC

No related DTCs.

Engine coolant temperature is above 60
C (140
F)

ªClosed loopº commanded air/fuel ratio is between
14.5 and 14.8.

Bank 1 HO2S 1 signal voltage remains above 952 mV
during normal ªclosed loopº operation for a total of 77
seconds over a 90-second period.
OR

Bank 1 HO2S 1 signal voltage remains above 500 mV
during ªdeceleration fuel cutoff modeº operation for 3
seconds.
Action Taken When the DTC Sets

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

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

ªOpen loopº fuel control will be in effect.
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 P0132 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0132 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.
Diagnostic Aids
Check the following items:

Fuel pressure ± The system will go rich if pressure is
too high. The PCM can compensate for some
increase. However, if fuel pressure is too high, a DTC
P0132 may be set. Refer to
Fuel System Diagnosis.

Perform ªInjector Balance Testº ± Refer to
Fuel System
Diagnosis.

6E±170
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS

Check the EVAP canister for fuel saturation ± If full of
fuel, check canister control and hoses. Refer to
Evaporative (EVAP) Emission Control System.

MAF sensor ±The system can go rich if MAF sensor
signal indicates an engine airflow measurement that is
not correct. Disconnect the MAF sensor to see it the
rich condition is corrected. If so, replace the MAF
sensor.

Check for a leak in the fuel pressure regulator
diaphragm by checking the vacuum line to the
regulator for the presence of fuel. There should be no
fuel in the vacuum line.

An intermittent TP sensor output will cause the system
to go rich due to a false indication of the engine
acceleration.

Shorted Heated Oxygen Sensor (HO2S) ±If the HO2S
is internally shorted, the HO2S voltage displayed on
the Tech 2 will be over 1 volt. Try disconnecting the
affected HO2S with the key ªONº, engine ªOFFº. If the
displayed HO2S voltage changes from over 1000 mV
to around 450 mV, replace the HO2S. Silicon
contamination of the HO2S can also cause a high
HO2S voltage to be indicated. This condition is
indicated by a powdery deposit on the portion of the
HO2S exposed to the exhaust stream. If
contamination is noticed, replace the affected HO2S.

Open HO2S Signal Circuit or Faulty HO2S±A poor
connection or open in the HO2S signal circuit cancause the DTC to set during deceleration fuel mode.
An HO2S which is faulty and not allowing a full voltage
swing between the rich and lean thresholds can also
cause this condition. Operate the vehicle by
monitoring the HO2S voltage with a Tech 2. If the
HO2S voltage is limited within a range between 300
mV to 600 mV, check the HO2S signal circuit wiring
and associated terminal conditions.

If none of the above conditions are present, replace the
affected HO2S.
Test Description
Number(s) below refer to the step number(s) on the
Diagnostic Chart.
3. DTC P0132 failing during ªdeceleration fuel cutoff
modeº operation may indicate a condition described
in the ªDiagnostic Aidsº above. If the DTC P0132
test passes while the Failure Records conditions are
being duplicated, an intermittent condition is
indicated.
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.
DTC P0132 ± HO2S Circuit High Voltage Bank 1 Sensor 1

StepActionValue(s)Ye sNo
1Was the ªOn-Board Diagnostic (OBD) System Checkº
performed?
ÐGo to Step 2
Go to OBD
System
Check
21. Install the Tech 2.
2. Run the engine at operating temperature.
3. Operate the vehicle within parameters specified
under ªConditions for Setting the DTCº included in
Diagnostic Support.
4. Using a Tech 2, monitor Bank 1 HO2S 1 voltage.
Does the Bank 1 HO2S 1 voltage remain above the
specified value?
952 mV (500
mV in
deceleration
fuel cutoff
mode)
Go to Step 4Go to Step 3
31. Ignition ªONº, review and record Tech 2 Failure
Records data.
2. Operate the vehicle within Failure Records
conditions as noted.
3. Using a Tech 2, monitor ªDTCº info for DTC P0132
until the DTC P0132 test runs.
4. Note the test result.
Does the Tech 2 indicate DTC P0132 failed this
ignition?
ÐGo to Step 4
Refer to
Diagnostic
Aids
41. Ignition ªOFFº.
2. Disconnect Bank 1 HO2S 1.
3. Ignition ªONº.
4. At HO2S Bank 1 Sensor 1 connector (PCM side)
use a DVM to measure voltages at the high and low
signal terminals.
Are the voltages in the specified range?
3-4 VGo to Step 5Go to Step 6

6E±172
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P0133 HO2S Slow Response Bank 1 Sensor 1
060R200054
Circuit Description
The powertrain control module (PCM) continuously
monitors the heated oxygen sensor (HO2S) activity for 90
seconds after ªclosed loopº has been enabled. During the
monitoring period the PCM counts the number of times
that a rich-to-lean and lean-to-rich response is indicated
and adds the amount of time it took to complete all
rich-to-lean transitions and lean-to-rich transitions. With
this information, an average time for rich-to-lean and
lean-to-rich transitions can be determined. If the average
response time of either transition is too slow, a DTC
P0133 will be set.
A lean-to-rich transition is indicated when the HO2S
voltage changes from less than 300 mV to greater than
600 mV. A rich-to-lean transition is indicated when the
HO2S voltage changes from more than 600 mV to less
than 300 mV. An HO2S that responds too slowly is likely
to be faulty and should be replaced.
Conditions for Setting the DTC

No related DTCs.

Engine coolant temperature (ETC) is above 60
C
(140
F).

Engine is operating in ªclosed loopº.

Engine has been running for at least 90 seconds.

Engine speed is between 1500 RPM and 3000 RPM.

Canister purge duty cycle is greater than 2%.
Mass air flow is between 18 g/second and 42 g/second.

All above conditions are met for 3 seconds.

90 seconds after ªclosed loopº has been enabled,
Bank1 HO2S 1 average transition time between
300 mV and 600 mV is too slow. The lean-to-rich
average transition response time was longer than 94
milliseconds or rich-to-lean average transition
response time was longer than 105 milliseconds.
Action Taken When the DTC Sets

The PCM will illuminate the malfunction indicator Lamp
(MIL) after the second consecutive trip in which 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.

ªOpen loopº fuel control will be in effect.
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 P0133 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0133 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.

6E±175
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
DTC P0133 ± HO2S Slow Response Bank 1 Sensor 1

 
StepNo Ye s Value(s) Action
14Visually/physically inspect the following items:

Ensure that the Bank 1 HO2S 1 is securely
installed.

Check for corrosion on terminals.

Check terminal tension (at Bank 1 HO2S 1 and at
the PCM).

Check for damaged wiring.
Was a problem found in any of the above areas?
ÐGo to Step 18Go to Step 15
151. Disconnect Bank 1 HO2S 1.
2. Ignition ªONº.
3. Using a DVM at the PCM side of the HO2S 1
connector, measure the voltage between the high
signal circuit and ground. Also measure the voltage
between the low signal circuit and ground.
Are both voltages in the specified range?
3-4 VGo to Step 16Go to Step 19
161. With Bank 1 HO2S 1 disconnected, jumper the high
and low (PCM side) signal circuits to ground.
2. Ignition ªONº.
3. Using a Tech 2, monitor the Bank 1 HO2S 1 voltage.
Does the Tech 2 indicate less than 10 mV and
immediately return to about 450 mV when the jumper is
removed?
ÐGo to Step 21Go to Step 22
17Replace the affected heated oxygen sensors.
NOTE: Before replacing sensors, the cause of the
contamination must be determined and corrected.

Fuel contamination.

Use of improper RTV sealant.

Engine oil/coolant consumption.
Is the action complete?
ÐVerify repairÐ
18Repair condition as necessary.
Is the action complete?
ÐVerify repairÐ
19Check for faulty PCM connections or terminal damage.
Is the action complete?
ÐVerify repairGo to Step 20
20Repair open, short or grounded signal circuit.
Is the action complete?
ÐVerify repairÐ
21Replace Bank 1 HO2S 1.
Is the action complete?
ÐVerify repairÐ
22Replace the PCM.
IMPORTANT:The replacement PCM must be
programmed. Refer to
On-Vehicle Service in
Powertrain Control Module and Sensors for
procedures.
And also refer to latest Service Bulletin.
Check to see if the Latest software is released or not.
And then Down Load the LATEST PROGRAMMED
SOFTWARE to the replacement PCM.
Is the action complete?
ÐVerify repairÐ

6E±176
6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
Diagnostic Trouble Code (DTC)
P0134 HO2S Circuit Insufficient Activity Bank 1 Sensor 1
060R200054
Circuit Description

The powertrain control module (PCM) supplies a bias
voltage of about 450 mV between the heated oxygen
sensor (HO2S) high and low circuits. When measured
with a 10 megaohm digital voltmeter, this may display
as low as 320 mV. The oxygen sensor varies the
voltage within a range of about 1000 mV when the
exhaust is rich, down through about 10 mV when
exhaust is lean. The PCM constantly monitors the
HO2S signal during ªclosed loopº operation and
compensates for a rich or lean condition by decreasing
or increasing injector pulse width as necessary. If the
Bank 1 HO2S 1 voltage remains at or near the 450 mV
bias for an extended period of time, DTC P0134 will be
set, indicating an open sensor signal or sensor low
circuit.

Heated oxygen sensors are used to minimize the
amount of time required for ªclosed loopº fuel control
operation and to allow accurate catalyst monitoring.
The oxygen sensor heater greatly decreases the
amount of time required for fuel control sensors Bank
1 HO2S 1 and Bank 2 HO2S 1 to become active.

Oxygen sensor heaters are required by post-catalyst
monitor sensors to maintain a sufficiently high
temperature for accurate exhaust oxygen content
readings further from the engine.
Conditions for Setting the DTC

No related DTCs.

Battery voltage is above 10 volts.
The engine has been running for over 5 seconds.

Engine coolant temperature (ETC) is above 60
C
(140
F).

Oxygen sensor heater has been determined to be
functioning properly.

Bank 1 HO2S 1 signal voltage remains between
400 mV and 500 mV for a total of 77 seconds over a
90-second period of time.
Action Take When the DTC Sets

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

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

ªOpen loopº fuel control will be in effect.
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 P0134 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

DTC P0134 can be cleared by using the Tech 2 ªClear
Infoº function or by disconnecting the PCM battery
feed.