Nissan Versa

 Sedan Service Manual

Engine » Engine control system (EC) » P014C, P014D, P015A, P015B, A/F sensor 1
DTC Logic

DTC DETECTION LOGIC

To judge malfunctions, 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 compensated time (the A/F signal cycling time index) is inordinately long or not.

DTC No.	Trouble diagnosis name	DTC detecting condition	Possible cause
P014C	Air fuel ratio (A/F) sensor 1 (bank 1) circuit slow response	The response time of a A/F sensor 1 signal delays more than the specified time computed by ECM.	Harness or connectors (The A/F sensor 1 circuit is open or shorted.) A/F sensor 1
P014D
P015A	Air fuel ratio (A/F) sensor 1 (bank 1) circuit delayed response
P015B

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 5.

2.PERFORM DTC CONFIRMATION PROCEDURE1

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. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1minute 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. Check the items status of "DATA MONITOR" as follows.

   NOTE: If "PRSNT" changed to "ABSNT", refer to EC, "Component Function Check".  

Is "PRSNT" displayed on CONSULT screen?

YES >> GO TO 4.

NO >> GO TO 3.

3.PERFORM DTC CONFIRMATION PROCEDURE2

With CONSULT

Perform DTC confirmation procedure1 again.

Is "PRSNT" displayed on CONSULT screen?

YES >> GO TO 4.

NO >> Refer to EC, "Component Function Check".

4.PERFORM DTC CONFIRMATION PROCEDURE2

With CONSULT

1. Wait for about 20 seconds at idle.
2. Check the items status of "DATA MONITOR" as follows.

   NOTE: If "CMPLT" changed to "INCMP", refer to EC, "Component Function Check".

Is "CMPLT" displayed on CONSULT screen?

YES >> GO TO 5.

NO >> Refer to EC, "Component Function Check".

5.PERFORM SELFDIAGNOSIS

With CONSULT

Check the "SELFDIAG RESULT".

Is any DTC detected?

YES >> Proceed to EC, "Diagnosis Procedure".

NO >> INSPECTION END

6.CHECK AIRFUEL RATIO SELFLEARNING 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, "Diagnosis Procedure".

NO >> INSPECTION END

DTC Logic

Diagnosis Procedure