Infiniti EX35. Manual - part 616

EC-206

< COMPONENT DIAGNOSIS >

[VQ35HR]

P0138, P0158 HO2S2

P0138, P0158 HO2S2

Description

INFOID:0000000003133370

The heated oxygen sensor 2, after three way catalyst 1, monitors the
oxygen level in the exhaust gas on each bank.
Even if switching characteristics of the air fuel ratio (A/F) sensor 1
are shifted, the air-fuel ratio is controlled to stoichiometric, by the sig-
nal from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates volt-
age from approximately 1V in richer conditions to 0V in leaner condi-
tions.
Under normal conditions the heated oxygen sensor 2 is not used for
engine control operation.

DTC Logic

INFOID:0000000003133371

DTC DETECTION LOGIC

The heated oxygen sensor 2 has a much longer switching time between rich and lean than the air fuel ratio (A/
F) sensor 1. The oxygen storage capacity of the three way catalyst 1 causes the longer switching time.
MALFUNCTION A
To judge the malfunctions of heated oxygen sensor 2, ECM monitors
whether the voltage is unusually high during the various driving con-
dition such as fuel-cut.

MALFUNCTION B
To judge the malfunctions of heated oxygen sensor 2, ECM monitors
whether the minimum voltage of sensor is sufficiently low during the
various driving condition such as fuel-cut.

SEF327R

PBIB1848E

PBIB2376E

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0138

Heated oxygen sensor 2 
(bank 1) circuit high volt-
age

A)

An excessively high voltage from the sen-
sor is sent to ECM.

• Harness or connectors

(The sensor circuit is open or shorted)

• Heated oxygen sensor 2

B)

The minimum voltage from the sensor is 
not reached to the specified voltage.

• Harness or connectors

(The sensor circuit is open or shorted)

• Heated oxygen sensor 2
• Fuel pressure
• Fuel injector

P0138, P0158 HO2S2

EC-207

< COMPONENT DIAGNOSIS >

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DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION A

1.

Start engine and warm it up to the normal operating temperature.

2.

Turn ignition switch OFF and wait at least 10 seconds.

3.

Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.

4.

Let engine idle for 2 minutes.

5.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to 

EC-209, "Diagnosis Procedure"

.

NO-1

>> With CONSULT-III: GO TO 3.

NO-2

>> Without CONSULT-III: GO TO 5.

3.

PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION B

NOTE:
For better results, perform “DTC WORK SUPPORT” at a temperature of 0 to 30 

°

C (32 to 86 

°

F).

1.

Select “DATA MONITOR” mode with CONSULT-III.

2.

Start engine and warm it up to the normal operating temperature.

3.

Turn ignition switch OFF and wait at least 10 seconds.

4.

Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.

5.

Let engine idle for 1 minute.

6.

Check that “COOLAN TEMP/S” indicates more than 70

°

C (158

°

F).

If not, warm up engine and go to next step when “COOLAN TEMP/S” indication reaches to 70

°

C (158

°

F).

7.

Open engine hood.

8.

Select “HO2S2 (B1) P1146” (for DTC P0138) or “HO2S2 (B2) P1166” (for DTC P0158) of “HO2S2” in
“DTC WORK SUPPORT” mode with CONSULT-III.

9.

Follow the instruction of CONSULT-III.
NOTE:
It will take at most 10 minutes until “COMPLETED” is displayed.

10. Touch “SELF-DIAG RESULTS”.
Which is displayed on CONSULT-III screen?

OK

>> INSPECTION END

NG

>> Go to 

EC-209, "Diagnosis Procedure"

.

CON NOT BE DIAGNOSED>>GO TO 4.

4.

PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION B AGAIN

1.

Turn ignition switch OFF and leave the vehicle in a cool place (soak the vehicle).

2.

Perform DTC confirmation procedure again.

>> GO TO 3.

5.

PERFORM COMPONENT FUNCTION CHECK FOR MALFUNCTION B

Perform component function check. Refer to 

EC-208, "Component Function Check"

.

P0158

Heated oxygen sensor 2 
(bank 2) circuit high volt-
age

A)

An excessively high voltage from the sen-
sor is sent to ECM.

• Harness or connectors

(The sensor circuit is open or shorted)

• Heated oxygen sensor 2

B)

The minimum voltage from the sensor is 
not reached to the specified voltage.

• Harness or connectors

(The sensor circuit is open or shorted)

• Heated oxygen sensor 2
• Fuel pressure
• Fuel injector

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

EC-208

< COMPONENT DIAGNOSIS >

[VQ35HR]

P0138, P0158 HO2S2

NOTE:
Use component function check to check the overall function of the heated oxygen sensor 2 circuit. During this
check, a 1st trip DTC might not be confirmed.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Go to 

EC-209, "Diagnosis Procedure"

.

Component Function Check

INFOID:0000000003133372

1.

PERFORM COMPONENT FUNCTION CHECK-I

Without CONSULT-III

1.

Start engine and warm it up to the normal operating temperature.

2.

Turn ignition switch OFF and wait at least 10 seconds.

3.

Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.

4.

Let engine idle for 1 minute.

5.

Check the voltage between ECM harness connector terminals under the following condition.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 2.

2.

PERFORM COMPONENT FUNCTION CHECK-II

Check the voltage between ECM harness connector terminals under the following condition.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 3.

3.

PERFORM COMPONENT FUNCTION CHECK-III

Check the voltage between ECM harness connector terminals under the following condition.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Go to 

EC-209, "Diagnosis Procedure"

.

DTC

ECM

Condition

Voltage

Connector

+

–

Terminal

Terminal

P0138

F102

76

84

Revving up to 4,000 rpm under no load at 
least 10 times

The voltage should be below 0.18 V at 
least once during this procedure.

P0158

80

DTC

ECM

Condition

Voltage

Connector

+

–

Terminal

Terminal

P0138

F102

76

84

Keeping engine at idle for 10 minutes

The voltage should be below 0.18 V at 
least once during this procedure.

P0158

80

DTC

ECM

Condition

Voltage

Connector

+

–

Terminal

Terminal

P0138

F102

76

84

Coasting from 80 km/h (50 MPH) in D po-
sition

The voltage should be below 0.18 V at 
least once during this procedure.

P0158

80

P0138, P0158 HO2S2

EC-209

< COMPONENT DIAGNOSIS >

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Diagnosis Procedure

INFOID:0000000003133373

1.

INSPECTION START

Confirm the detected malfunction (A or B). Refer to 

EC-206, "DTC Logic"

.

Which malfunction is detected?

A

>> GO TO 2

B

>> GO TO 9.

2.

CHECK GROUND CONNECTION

1.

Turn ignition switch OFF.

2.

Check ground connection M95. Refer to Ground Inspection in 

GI-41, "Circuit Inspection"

.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair or replace ground connection.

3.

CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT

1.

Disconnect heated oxygen sensor 2 (HO2S2)harness connector.

2.

Disconnect ECM harness connector.

3.

Check the continuity between HO2S2 harness connector and ECM harness connector.

4.

Also check harness for short to ground and short to power.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair open circuit or short to ground or short to power in harness or connectors.

4.

CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Check the continuity between HO2S2 harness connector and ECM harness connector.

2.

Check the continuity between HO2S2 harness connector or ECM harness connector and ground.

3.

Also check harness for short to power.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Repair open circuit or short to ground or short to power in harness or connectors.

5.

CHECK HO2S2 CONNECTOR FOR WATER

Check connectors for water.

Is the inspection result normal?

DTC

HO2S2

ECM

Continuity

Bank

Connector

Terminal

Connector

Terminal

P0138

1

F54

1

F102

84

Existed

P0158

2

F53

1

DTC

HO2S2

ECM

Continuity

Bank

Connector

Terminal

Connector

Terminal

P0138

1

F54

4

F102

76

Existed

P0158

2

F53

4

80

DTC

HO2S2

ECM

Ground

Continuity

Bank

Connector

Terminal

Connector

Terminal

P0138

1

F54

4

F102

76

Ground

Not existed

P0158

2

F53

4

80

Water should not exist.