Nissan Murano: Dtc/circuit Diagnosis / P014c A/f Sensor 1

DTC Description

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.

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

POSSIBLE CAUSE

P014C

• Harness or connectors (The A/F sensor 1 circuit is open or shorted.)

• A/F sensor 1

P014D

• Harness or connectors (The A/F sensor 1 circuit is open or shorted.)

• A/F sensor 1

P014E

• Harness or connectors (The A/F sensor 1 circuit is open or shorted.)

• A/F sensor 1

P014F

• Harness or connectors (The A/F sensor 1 circuit is open or shorted.)

• A/F sensor 1

P015A

• Harness or connectors (The A/F sensor 1 circuit is open or shorted.)

• A/F sensor 1

P015B

• Harness or connectors (The A/F sensor 1 circuit is open or shorted.)

• A/F sensor 1

P015C

• Harness or connectors (The A/F sensor 1 circuit is open or shorted.)

• A/F sensor 1

P015D

• Harness or connectors (The A/F sensor 1 circuit is open or shorted.)

• A/F sensor 1

FAIL-SAFE

Not applicable

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?

GO TO 2.

GO TO 6.

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. 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 Component Function Check.

   DTC	Data monitor item	Status
   P014C P014D P015A P015B	A/F SEN1 DIAG3 (B1)	PRSNT
   P014E P014F P015C P015D	A/F SEN1 DIAG3 (B2)

Is “PRSNT” displayed on CONSULT screen?

GO TO 4.

GO TO 3.

PERFORM DTC CONFIRMATION PROCEDURE-2

With CONSULT

Perform DTC confirmation procedure-1 again.

Is “PRSNT” displayed on CONSULT screen?

GO TO 4.

Refer to Component Function Check.

PERFORM DTC CONFIRMATION PROCEDURE-2

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 Component Function Check.

   DTC	Data monitor item	Status
   P014C P014D P015A P015B	A/F SEN1 DIAG1 (B1)	CMPLT
   	A/F SEN1 DIAG2 (B1)
   P014E P014F P015C P015D	A/F SEN1 DIAG1 (B2)
   	A/F SEN1 DIAG2 (B2)

Is “CMPLT” displayed on CONSULT screen?

GO TO 5.

Refer to Component Function Check.

PERFORM SELF-DIAGNOSIS

With CONSULT

Check the “SELF-DIAG RESULT”.

Is any DTC detected?

Proceed to Diagnosis Procedure.

To check malfunction symptom before repair: Refer to Intermittent Incident.

Confirmation after repair: INSPECTION END

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%?

GO TO 8.

GO TO 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.

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?

Proceed to Diagnosis Procedure.

To check malfunction symptom before repair: Refer to Intermittent Incident.

Confirmation after repair: INSPECTION END

RETIGHTEN A/F SENSOR 1

Loosen and retighten the A/F sensor 1. Refer to Removal and Installation (bank 2), Removal and Installation (bank 1).

GO TO 2.

CHECK EXHAUST GAS LEAK

1. Start engine and run it at idle.

2. Listen for an exhaust gas leak before three way catalyst 1.

   

Is exhaust gas leak detected?

Repair or replace.

GO TO 3.

CHECK FOR INTAKE AIR LEAK

Listen for an intake air leak after the mass air flow sensor.

Is intake air leak detected?

Repair or replace.

GO TO 4.

CLEAR THE MIXTURE RATIO SELF-LEARNING VALUE

1. Clear the mixture ratio self-learning value. Refer to Description.

2. Run engine for at least 10 minutes at idle speed.

Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected? Is it difficult to start engine?

Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to DTC Description or DTC Description.

GO TO 5.

CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY

1. Disconnect A/F sensor 1 harness connector.

2. Turn ignition switch ON.

3. Check the voltage between A/F sensor 1 harness connector and ground.

   DTC	A/F sensor 1			Ground	Voltage
   	Bank	Connector	Terminal
   P014C P014D P015A P015B	1	F12	1	Ground	Battery voltage
   P014E P014F P015C P015D	2	F61	1

Is the inspection result normal?

GO TO 7.

GO TO 6.

CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT

1. Turn ignition switch OFF.

2. Disconnect IPDM E/R harness connector.

3. Check the continuity between A/F sensor 1 harness connector and IPDM E/R harness connector.

Is the inspection result normal?

Perform the trouble diagnosis for power supply circuit.

Repair or replace error-detected parts.

CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch OFF.

2. Disconnect ECM harness connector.

3. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.

   DTC	A/F sensor 1			ECM		Continuity
   	Bank	Connector	Terminal	Connector	Terminal
   P014C P014D P015A P015B	1	F12	3	F79	66	Existed
   			4		67
   P014E P014F P015C P015D	2	F61	3		76
   			4		77

4. Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector and ground.

   DTC	A/F sensor 1			Ground	Continuity
   	Bank	Connector	Terminal
   P014C P014D P015A P015B	1	F12	3	Ground	Not existed
   			4
   P014E P014F P015C P015D	2	F61	3
   			4

   DTC	ECM			Ground	Continuity
   	Bank	Connector	Terminal
   P014C P014D P015A P015B	1	F79	66	Ground	Not existed
   			67
   P014E P014F P015C P015D	2		76
   			77

5. Also check harness for short to power.

Is the inspection result normal?

GO TO 8.

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

CHECK AIR FUEL RATIO (A/F) SENSOR 1 HEATER

Check air fuel ratio (A/F) sensor 1 heater. Refer to Component Inspection.

Is the inspection result normal?

GO TO 9.

Replace malfunctioning air fuel ratio (A/F) sensor 1. Refer to Removal and Installation (bank 2), Removal and Installation (bank 1).

CHECK MASS AIR FLOW SENSOR

Check both mass air flow sensor (bank 1 and bank 2). Refer to Component Inspection.

Is the inspection result normal?

GO TO 10.

Replace malfunctioning mass air flow sensor. Refer to Removal and Installation.

CHECK PCV VALVE

Check PCV valve. Refer to Work Procedure.

Is the inspection result normal?

INSPECTION END

Repair or replace PCV valve. Refer to Component Parts Location.