Opel Frontera UBS. Manual - part 2143

6E–145

ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0134 HO2S Circuit Insufficient Activity Bank 1

Sensor 1

060RW237

Circuit Description

D

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 “closed loop” 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.

D

Heated oxygen sensors are used to minimize the
amount of time required for “closed loop” 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.

D

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

D

No related DTCs.

D

Battery voltage is above 10 volts.

D

Engine run time is longer than 40 seconds.

D

Oxygen sensor heater has been determined to be
functioning properly.

D

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

D

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

D

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

D

“Open loop” fuel control will be in effect.

Conditions for Clearing the MIL/DTC

D

DTC P0134 can be cleared by using Tech 2 “Clear Info”
function or by disconnecting the PCM battery feed.

Diagnostic Aids

Check for the following conditions:

D

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

D

Faulty HO2S heater or heater circuit – With the ignition
“ON,” engine “OFF,” after a cool down period, the
HO2S 1 voltage displayed on Tech 2 is normally
455-460 mV.  A reading over 1000 mV indicates a
signal line shorted to voltage.  A reading under 5 mV

6E–146

ENGINE DRIVEABILITY AND EMISSIONS

indicates a signal line shorted to ground or signal lines
shorted together.  Disconnect the HO2S and connect
a test light between the HO2S ignition feed and heater
ground circuits.  If the test light does not light for 2
seconds when the ignition is turned on, repair the open
ignition feed or sensor ground circuit as necessary.  If
the test light lights and the HO2S signal and low circuits
are OK, replace the HO2S.

D

Intermittent test – With the Ignition “ON,” monitor the
HO2S signal voltage while moving the wiring harness
and related connectors.  If the fault is induced, the
HO2S signal voltage will change.  This may help isolate
the location of the malfunction.

Test Description

Number(s) below refer to the step number(s) on the
Diagnostic Chart.
3. If the DTC P0134 test passes while the Failure

Records conditions are being duplicated, an
intermittent conditions 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 P0134 –HO2S Circuit  Insufficient Activity Bank 1 Sensor 1

 

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. Install Tech 2.
2. Run the engine at operating temperature.
3. Operate the engine above 1200 RPM for two

minutes.

Does Tech 2 indicate Bank 1 HO2S 1 voltage varying
outside the specified values?

400-500 mV

Go to 

Step 3

Go to 

Step 4

3

1. Ignition “ON,” engine “OFF,” review and record Tech

2 Failure Records data and note parameters.

2. Operate the vehicle within Failure Records

conditions as noted.

3. Using Tech 2, monitor “Specific DTC” info for DTC

P0134 until the DTC P0134 test runs.

4. Note the test result.

Does Tech 2 indicate DTC P0134 failed this ignition?

—

Go to 

Step 4

Refer to

Diagnostic

Aids

4

Check for a damaged harness.

Was a problem found?

—

Verify repair

Go to 

Step 5

5

Check for poor Bank 1 HO2S 1 high and low circuit
terminal connections at the Bank 1 HO2S 1 harness
connector and replace terminal(s) if necessary.

Did any terminals require replacement?

—

Verify repair

Go to 

Step 6

6

Check for poor Bank 1 HO2S 1 high and low circuit
terminal connections at the PCM and replace terminals
if necessary.

Did any terminals require replacement?

—

Verify repair

Go to 

Step 7

7

1. Ignition “OFF.”
2. With the PCM disconnected, check continuity of the

Bank 1 HO2S 1 high circuit.

3. If the Bank 1 HO2S 1 high circuit measures over 5.0

ohms, repair open or poor connection as necessary.

Was a Bank 1 HO2S 1 high circuit problem found and
corrected?

—

Verify repair

Go to 

Step 8

6E–147

ENGINE DRIVEABILITY AND EMISSIONS

DTC P0134 –HO2S Circuit  Insufficient Activity Bank 1 Sensor 1

  (Cont'd)

Step

No

Yes

Value(s)

Action

8

1. Ignition “OFF.”
2. With the PCM disconnected, check continuity of the

Bank 1 HO2S 1 low circuit.

3. If the Bank 1 HO2S 1 low circuit measures over 5

ohms, repair open or poor connection as necessary.

Was a Bank 1 HO2S 1 low circuit problem found and
corrected?

—

Verify repair

Go to 

Step 9

9

1. Ignition “ON,” engine “OFF.”
2. Disconnect Bank 1 HO2S 1 and jumper the HO2S

high and low circuits (PCM side) to ground.

3. Using Tech 2, monitor Bank 1 HO2S 1 voltage.

Is Bank 1 HO2S 1 voltage in the specified range?

0-10 mV

Go to 

Step 10

Go to 

Step 11

10

Replace Bank 1 HO2S 1.

Is the action complete?

—

Verify repair

—

11

Replace the PCM.

IMPORTANT: The replacement PCM must be
programmed.  Refer to 

UBS 98model year Immobilizer

Workshop Manual.

Is the action complete?

—

Verify repair

—

6E–148

ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) P0151 HO2S Circuit Low Voltage Bank 2 

Sensor 1

060RW190

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 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 “closed loop” operation and compensates for a rich
or lean condition by decreasing or increasing injector
pulse width as necessary.  If the Bank 2 HO2S 1 voltage
remains excessively low for an extended period of time,
DTC P0151 will be set.

Conditions for Setting the DTC

D

No related DTCs.

D

The engine is operating in “closed loop.”

D

Engine coolant temperature is above 60

°

C (140

°

F).

D

“Closed loop” commanded air/fuel ratio is between
14.5 and 14.8.

D

Throttle angle is between 3% and 19%.

D

Bank 2 HO2S 1 signal voltage remains below 22 mV
during normal “closed loop” operation for a total of 77
seconds over a 90-second period of time.

Action Taken When the DTC Sets

D

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

D

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

D

“Open loop” fuel control will be in effect.

Conditions for Clearing the MIL/DTC

D

DTC P0151 can be cleared by using Tech 2 “Clear Info”
function or by disconnecting the PCM battery feed.

Diagnostic Aids

Check for the following conditions:

D

Heated oxygen sensor wiring – The sensor pigtail may
be mispositioned and contacting the exhaust system.

D

Poor PCM to engine block grounds.

D

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
P0151 may be set.  Refer to 

Fuel System Diagnosis.

D

Lean injector(s) – Perform “Injector Balance Test.”

D

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

D

Exhaust leaks – An exhaust leak may cause outside air
to be pulled into the exhaust gas stream past the
HO2S, causing the system to appear lean.  Check for