Nissan Sentra. Manual - part 385

EC-236

< DTC/CIRCUIT DIAGNOSIS >

[MRA8DE]

P0139 HO2S2

7. Check “HO2S2 (B1)” at idle speed when adjusting “FUEL INJECTION” to 

± 25%.

“HO2S2 (B1)” should be above 0.72 V at least once when the “FUEL INJECTION” is + 25%.

“HO2S2 (B1)” should be below 0.18 V at least once when the “FUEL INJECTION” is 

− 25%.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace heated oxygen sensor 2. Refer to 

EX-5, "Exploded View"

.

3.

CHECK HEATED OXYGEN SENSOR 2-1

Without CONSULT

1. Start engine and warm it up to 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 and ground as per the following condition.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 4.

4.

CHECK HEATED OXYGEN SENSOR 2-2

Check the voltage between ECM harness connector and ground as per the following condition.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 5.

5.

CHECK HEATED OXYGEN SENSOR 2-3

Check the voltage between ECM harness connector and ground as per the following condition.

JPBIA5998GB

ECM

Condition

Voltage

Connector

+

−

Terminal

F24

22

23

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

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

ECM

Condition

Voltage

Connector

+

−

Terminal

F24

22

23

Keeping engine speed at idle for 
10 minutes

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

P0139 HO2S2

EC-237

< DTC/CIRCUIT DIAGNOSIS >

[MRA8DE]

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Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace heated oxygen sensor 2. Refer to 

EX-5, "Exploded View"

.

ECM

Condition

Voltage

Connector

+

−

Terminal

F24

22

23

Coasting from 80 km/h (50 
MPH) in D position (CVT), 5th 
position (6MT)

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

EC-238

< DTC/CIRCUIT DIAGNOSIS >

[MRA8DE]

P014C, P014D, P015A, P015B A/F SENSOR 1

P014C, P014D, P015A, P015B A/F SENSOR 1

DTC Logic

INFOID:0000000009758494

DTC DETECTION LOGIC

To judge the malfunction of A/F sensor 1, this diagnosis measures response time of the A/F signal computed

by ECM from the A/F sensor 1 signal. The time is compensated by engine operating (speed and load), fuel

feedback control constant, and the A/F sensor 1 temperature index. Judgment is based on whether the com-

pensated time (the A/F signal cycling time index) is inordinately long or not.

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure

before conducting the next test.

1. Turn ignition switch OFF and wait at least 10 seconds.

2. Turn ignition switch ON.

3. Turn ignition switch OFF and wait at least 10 seconds.

TESTING CONDITION:

Before performing the following procedure, confirm that battery voltage is more than 11 V at idle.
Do you have CONSULT?

YES

>> GO TO 2.

NO

>> GO TO 6.

2.

PERFORM DTC CONFIRMATION PROCEDURE-1

With CONSULT

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

2. Turn ignition switch OFF and wait at least 10 seconds.

3. Turn ignition switch ON.

4. Turn ignition switch OFF and wait at least 10 seconds.

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

load.

6. Let engine idle for 1 minute.

7. Increase the engine speed up to about 3,600 rpm and keep it for 10 seconds.

8. Fully release accelerator pedal and then let engine idle for about 1 minute.

9. On CONSULT screen, select “ENGINE” >> “DATA MONITOR” >> “A/F SEN1 DIAG3 (B1)”.

10. Check that the data monitor indicates “PRSNT”.

NOTE:

If “PRSNT” changed to “ABSNT”, refer to 

EC-211, "Component Function Check"

.

Is “PRSNT” displayed on CONSULT screen?

YES

>> GO TO 4

NO

>> GO TO 3.

3.

PERFORM DTC CONFIRMATION PROCEDURE-2

With CONSULT

Perform DTC confirmation procedure-1 again.

DTC No.

CONSULT screen terms

(Trouble diagnosis content)

DTC detecting condition

Possible cause

P014C

A/F SENSOR1 (B1)
(O2 sensor slow response - 
rich to lean bank 1 sensor 
1)

The response time of a A/F sensor 1 signal delays 
more than the specified time computed by ECM.

• Harness or connectors

(A/F sensor 1 circuit is open or 
shorted.)

• A/F sensor 1
• A/F sensor 1 heater
• Fuel pressure
• Fuel injector
• Intake air leaks
• Exhaust gas leaks
• PCV
• Mass air flow sensor

P014D

A/F SENSOR1 (B1)
(O2 sensor slow response - 
lean to rich bank 1 sensor 
1)

P014C, P014D, P015A, P015B A/F SENSOR 1

EC-239

< DTC/CIRCUIT DIAGNOSIS >

[MRA8DE]

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Is “PRSNT” displayed on CONSULT screen?

YES

>> GO TO 4.

NO

>> Proceed to 

EC-211, "Component Function Check"

.

4.

PERFORM DTC CONFIRMATION PROCEDURE-3

With CONSULT

1. Wait for about 20 seconds at idle.

2. On CONSULT screen, select “ENGINE” >> “DATA MONITOR” >> “A/F SEN1 DIAG2 (B1)”.

3. Check that the data monitor indicates “CMPLT”.

NOTE:

If “CMPLT” changed to “INCMP”, refer to 

EC-211, "Component Function Check"

.

Is “CMPLT” displayed on CONSULT screen?

YES

>> GO TO 5.

NO

>> Refer to 

EC-211, "Component Function Check"

.

5.

PERFORM SELF-DIAGNOSIS

With CONSULT

Check the “SELF-DIAG RESULT”.
Is any DTC detected?

YES

>> Proceed to 

EC-240, "Diagnosis Procedure"

.

NO

>> INSPECTION END

6.

CHECK AIR-FUEL RATIO SELF-LEARNING VALUE

With GST

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

2. Select Service $01 with GST.

3. Calculate the total value of “Short term fuel trim” and “Long term fuel trim” indications.
Is the total percentage within 

±15%?

YES

>> GO TO 8.

NO

>> GO TO 7.

7.

DETECT MALFUNCTIONING PART

Check the following.

• Intake air leaks

• Exhaust gas leaks

• Incorrect fuel pressure

• Lack of fuel

• Fuel injector

• Incorrect PCV hose connection

• PCV  valve

• Mass air flow sensor

>> Repair or replace malfunctioning part.

8.

PERFORM DTC CONFIRMATION PROCEDURE

1. Turn ignition switch OFF and wait at least 10 seconds.

2. Turn ignition switch ON.

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. Increase the engine speed up to about 3,600 rpm and keep it for 10 seconds.

7. Fully release accelerator pedal and then let engine idle for about 1 minute.

8. Check 1st trip DTC.
Is 1st trip DTC detected?

YES

>> Proceed to 

EC-240, "Diagnosis Procedure"

.

NO

>> INSPECTION END