Opel Frontera UE. Manual - part 939

 

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Opel Frontera UE. Manual - part 939

 

 

6E2–142

6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) 

P0151 HO2S Circuit Low Voltage Bank 2 Sensor 1

D06RX139

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

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

D

A history DTC P0151 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

D

DTC P0151 can be cleared by using the 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.”

6E2–143

6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

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
exhaust leaks that may cause a false lean condition to
be indicated.

D

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

D

Fuel contamination – Water, even in small amounts,
can be delivered to the fuel injectors.  The water can
cause a lean exhaust to be indicated.  Excessive
alcohol in the fuel can also cause this condition.  Refer
to 

Fuel System Diagnosis for the procedure to check

for fuel contamination.

D

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 P0151 failing during operation may indicate a

condition described in the “Diagnostic Aids” above.
If the DTC P0151 test passes while the Failure
Records conditions are being duplicated, an
intermittent condition is indicate.

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 P0151 — HO2S Circuit Low Voltage Bank 2 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 the Tech 2.
2. Run the engine at operating temperature.
3. Operate the vehicle within the parameters specified

under “Conditions for Setting the DTC” criteria
included in Diagnostic Support.

4. Using a Tech 2, monitor Bank 2 HO2S 1 voltage.

Does the Bank 2 HO2S 1 voltage remain below the
specified value?

22 mV

Go to 

Step 4

Go to 

Step 3

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 a Tech 2, monitor “DTC” info for DTC P0151

until the DTC P0151 test runs.

4. Note test result.

Does the Tech 2 indicate DTC P0151 failed this
ignition?

Go to 

Step 4

Refer to

Diagnostic

Aids

4

1. Turn ignition “OFF.”
2. Disconnect the PCM.
3. Check the Bank 2 HO2S 1 high and low signal

circuits for a short to ground or a short to the heater
ground circuit.

Were Bank 2 HO2S 1 signal circuits shorted?

Go to 

Step 5

Go to 

Step 6

5

Repair the Bank 2 HO2S 1 signal circuit.

Is the action complete?

Verify repair

6

1. Ignition “OFF.”
2. Leave the PCM and HO2S 1 disconnected.
3. Check for continuity between the high and low

signal circuits.

Was there continuity between the high and low circuits?

Go to 

Step 7

Go to 

Step 8

6E2–144

6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

DTC P0151 — HO2S Circuit Low Voltage Bank 2 Sensor 1

  (Cont'd)

Step

No

Yes

Value(s)

Action

7

Repair the short between the high and low circuits.

Is the action complete?

Verify repair

8

1. Ignition “OFF.”
2. Reconnect the PCM, leave HO2S 1 disconnected.
3. Ignition “ON.”

Does the Tech 2 indicate Bank 2 HO2S 1 voltage near
the specified value?

425-475 mV

Refer to

Diagnostic

Aids

Go to 

Step 9

9

Replace the PCM.

Is the action complete?

Verify repair

6E2–145

6VD1 3.2L ENGINE DRIVEABILITY AND EMISSIONS

Diagnostic Trouble Code (DTC) 

P0152 HO2S Circuit High Voltage Bank 2 Sensor 1

D06RX139

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 the injector
pulse width as necessary.  If the Bank 2 HO2S 1 voltage
remains excessively high for an extended period of time,
DTC P0152 will be set.

Conditions for Setting the DTC

D

No related DTCs.

D

The engine is operating in “closed loop.”

D

The engine coolant temperature is above 60

°

C

(140

°

F).

D

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

D

Throttle angle between 3% and 19%.

D

Bank 2 HO2S 1 signal voltage remains above 952 mV
during normal “closed loop” operation for a total of 77
seconds over a 90-second period.

OR

D

Bank 2 HO2S 1 signal voltage remains above 500 mV
during deceleration fuel cutoff mode operation for up to
3 seconds.

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

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

D

A history DTC P0152 will clear after 40 consecutive
warm-up cycles have occurred without a fault.

D

DTC P0152 can be cleared by using the Tech 2 “Clear
Info” function or by disconnecting the PCM battery
feed.

Diagnostic Aids

Check for the following conditions:

D

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
P0152 may be set.  Refer to 

Fuel System Diagnosis.

D

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

 

 

 

 

 

 

 

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