P014C, P014D, P015A, P015B, A/F SENSOR 1EC-289
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P014C, P014D, P015A, P015B, A/F SENSOR 1
DTC LogicINFOID:0000000009462232
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 engi ne operating (speed and load), fuel feedback control con-
stant, 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 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. 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-195, "Component Function Check"
.
Is
“PRSNT” displayed on CONSULT screen?
YES >> GO TO 4.
NO >> GO TO 3.
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 de-lays 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
A/F SENSOR1 (B1)
(O2 sensor slow response - lean
to rich bank 1 sensor 1)
P015A A/F SENSOR1 (B1)
(O2 sensor delayed response -
rich to lean bank 1 sensor 1)
P015B A/F SENSOR1 (B1)
(O2 sensor delayed response -
lean to rich bank 1 sensor 1)
Data monitor item Status
A/F SEN1 DIAG3 (B1) PRSNT
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
EC-290
< DTC/CIRCUIT DIAGNOSIS >[QR25DE]
P014C, P014D, P015A,
P015B, A/F SENSOR 1
3.PERFORM DTC CONFIRMATION PROCEDURE-2
With CONSULT
Perform DTC confirmation procedure-1 again.
Is
“PRSNT” displayed on CONSULT screen?
YES >> GO TO 4.
NO >> Refer to EC-195, "Component Function Check"
.
4.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 EC-195, "Component Function Check"
.
Is
“CMPLT” displayed on CONSULT screen?
YES >> GO TO 5.
NO >> Refer to EC-195, "Component Function Check"
.
5.PERFORM SELF-DIAGNOSIS
With CONSULT
Check the “SELF-DIAG RESULT”.
Is any DTC detected?
YES >> Proceed to EC-291, "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.
Data monitor item Status
A/F SEN1 DIAG1 (B1) CMPLT
A/F SEN1 DIAG2 (B1)
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
P014C, P014D, P015A, P015B, A/F SENSOR 1EC-291
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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-291, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000009462233
1.RETIGHTEN A/F SENSOR 1
Loosen and retighten the A/F sensor 1. Refer to EM-33, "Exploded View"
.
>> GO TO 2.
2.CHECK EXHAUST GAS LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst (manifold).
Is exhaust gas leak detected?
YES >> Repair or replace.
NO >> GO TO 3.
3.CHECK FOR INTAKE AIR LEAK
Listen for an intake air leak after the mass air flow sensor.
Is intake air leak detected?
YES >> Repair or replace.
NO >> GO TO 4.
4.CLEAR THE MIXTURE RATIO SELF-LEARNING VALUE
1. Clear the mixture ratio self-learning value. Refer to EC-181, "Work Procedure"
.
2. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171 or P172 detected? Is it difficult to start engine?
YES >> Perform trouble diagnosis for DTC P0171 or P0172. Refer to EC-294, "DTC Logic" or EC-298,
"DTC Logic".
NO >> GO TO 5.
5.CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT
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.
Is the inspection result normal?
PBIB1216E
+
– Voltage
A/F sensor 1
Connector Terminal F24 4 Ground Battery voltage
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
EC-292
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P014C, P014D, P015A,
P015B, A/F SENSOR 1
YES >> GO TO 6.
NO >> Repair or replace error-detected parts.
6.CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT
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.
*1: Except for California
*2: For California
4. Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector
and ground.
*1: Except for California
*2: For California
5. Also check harness for short to power.
Is the inspection result normal?
YES >> GO TO 7.
NO >> Repair or replace error-detected parts.
7.CHECK AIR FUEL RATIO (A/F) SENSOR 1 HEATER
Refer to EC-216, "Component Inspection"
.
Is the inspection result normal?
YES >> GO TO 8.
NO >> GO TO 11.
8.CHECK MASS AIR FLOW SENSOR
Refer to EC-230, "Component Inspection"
.
Is the inspection result normal?
YES >> GO TO 9.
NO >> Replace mass air flow sensor. Refer to EM-29, "Exploded View"
.
9.CHECK PCV VALVE
Refer to EC-539, "Inspection"
.
Is the inspection result normal?
YES >> GO TO 10.
+–
Continuity
A/F sensor 1 ECM
Connector Terminal Connector Terminal
F24 1
F14
*1
F91*2
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Existed
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+ –Continuity
A/F sensor 1
Connector Terminal
F24 1
Ground Not existed
2
+ –Continuity
ECM
Connector Terminal
F14
*1
F91*2
41 Ground Not existed
45
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
P014C, P014D, P015A, P015B, A/F SENSOR 1EC-293
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NO >> Repair or replace PCV valve. Refer to
EC-21, "Component Parts Location".
10.CHECK INTERMITTENT INCIDENT
Perform GI-43, "Intermittent Incident"
.
Is the inspection result normal?
YES >> GO TO 11.
NO >> Repair or replace.
11 .REPLACE AIR FUEL RATIO (A/F) SENSOR 1
Replace air fuel ratio (A/F) sensor 1. Refer to EM-33, "Exploded View"
.
CAUTION:
• Discard any sensor which has been dropped from a he ight of more than 0.5 m (19.7 in) onto a hard
surface such as a concrete floor; use a new one.
• Before installing new sensor, clean exhaust syst em threads using Oxygen Sensor Thread Cleaner
[commercial service tool (J-43897-18 or J43897-12)] and approved Anti-seize Lubricant (commercial
service tool).
>> INSPECTION END
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
EC-294
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P0171 FUEL INJECTION SYSTEM FUNCTION
P0171 FUEL INJECTIO
N SYSTEM FUNCTION
DTC LogicINFOID:0000000009462234
DTC DETECTION LOGIC
With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio f eedback signal from the A/F sensors 1. The ECM calcu-
lates the necessary compensation to correct the of fset between the actual and the theoretical ratios.
In case the amount of the compensation value is extrem ely large (The actual mixture ratio is too lean.), the
ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic).
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.
>> GO TO 2.
2.PERFORM DTC CONFIRMATION PROCEDURE-1
1. Clear the mixture ratio self-learning value. Refer to EC-181, "Work Procedure"
.
2. Start engine.
Is it difficult to start engine?
YES >> GO TO 3.
NO >> GO TO 4.
3.RESTART ENGINE
If it is difficult to start engine, the f uel injection system has a malfunction, too.
Crank engine while depressing accelerator pedal.
NOTE:
When depressing accelerator pedal three-fourths (3/4 ) or more, the control system does not start the
engine. Do not depress accelerator pedal too much.
Does engine start?
YES >> Proceed to EC-295, "Diagnosis Procedure".
NO >> Check exhaust and intake air leak visually.
4.PERFORM DTC CONFIRMATION PROCEDURE-2
1. Start engine and let it idle for at least 5 minutes.
2. Check 1st trip DTC.
Is 1st trip DTC detected?
Sensor Input signal to ECM ECM function Actuator
A/F sensor 1 Density of oxygen in exhaust gas
(Mixture ratio feedback signal) Fuel injection control Fuel injector
DTC No.CONSULT screen terms
(Trouble diagnosis content) DTC detecting condition Possible cause
P0171 FUEL SYS-LEAN-B1
(System too lean bank 1) • Fuel injection system does not operate properly.
• The amount of mixture ratio compensation is too
large. (The mixture ratio is too lean.) • Intake air leaks
• A/F sensor 1
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel pressure
• Lack of fuel
• Mass air flow sensor
• Incorrect PCV hose connection
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
P0171 FUEL INJECTION SYSTEM FUNCTIONEC-295
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YES >> Proceed to
EC-295, "Diagnosis Procedure".
NO >> GO TO 5.
5.PERFORM DTC CONFIRMATION PROCEDURE-3
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Start engine.
3. Maintain the following conditions for at least 10 consecutive minutes.
Hold the accelerator pedal as steady as possible.
CAUTION:
Always drive vehicle at a safe speed.
4. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to EC-295, "Diagnosis Procedure".
NO >> INSPECTION END
Diagnosis ProcedureINFOID:0000000009462235
1.CHECK EXHAUST GAS LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst (manifold).
Is exhaust gas leak detected?
YES >> Repair or replace error-detected parts.
NO >> GO TO 2.
2.CHECK FOR INTAKE AIR LEAK
1. Listen for an intake air leak after the mass air flow sensor.
2. Check PCV hose connection.
Intake air leak detected?
YES >> Repair or replace error-detected parts.
NO >> GO TO 3.
3.CHECK A/F SENSOR 1 IN PUT SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect corresponding A/F sensor 1 harness connector.
3. Disconnect ECM harness connector.
4. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.
*1: Except for California
*2: For California
VHCL SPEED SE 50 - 120 km/h (31 - 75 MPH)
PBIB1216E
+ −
Continuity
A/F sensor 1 ECM
Connector Terminal Connector Terminal
F24 1
F14
*1
F91*2
41
Existed
245
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
EC-296
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P0171 FUEL INJECTION SYSTEM FUNCTION
5. Check the continuity between A/F sensor 1
harness connector and ground, or ECM harness connector
and ground.
*1: Except for California
*2: For California
6. Also check harness for short to power.
Is the inspection result normal?
YES >> GO TO 4.
NO >> Repair or replace error-detected parts.
4.CHECK FUEL PRESSURE
Check fuel pressure. Refer to EC-182, "Work Procedure"
.
Is the inspection result normal?
YES >> GO TO 6.
NO >> GO TO 5.
5. DETECT MALFUNCTIONING PART
Check fuel hoses and fuel tubes for clogging. Refer to EM-41, "Exploded View"
.
Is the inspection result normal?
YES >> Replace “fuel filter and fuel pump assembly”. Refer to FL-6, "Removal and Installation".
NO >> Repair or replace error-detected parts.
6.CHECK MASS AIR FLOW SENSOR
With CONSULT
1. Install all removed parts.
2. Check “MASS AIR FLOW” in “DATA MONITO R” mode of “ENGINE” using CONSULT.
3. For specification, refer to EC-541, "Mass Air Flow Sensor"
.
With GST
1. Install all removed parts.
2. Check mass air flow sensor signal in Service $01 with GST.
3. For specification, refer to EC-541, "Mass Air Flow Sensor"
.
Is the measurement value within the specification?
YES >> GO TO 7.
NO >> Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or grounds. Refer to EC-232, "DTC Logic"
.
7.CHECK FUNCTION OF FUEL INJECTOR
With CONSULT
1. Start engine.
2. Perform “POWER BALANCE” in “ACTIVE TEST” mode of “ENGINE” using CONSULT.
3. Make sure that each circuit produces a momentary engine speed drop.
Without CONSULT
+ −Continuity
A/F sensor 1
Connector Terminal
F24 1
Ground Not existed
2
+ −Continuity
ECM
Connector Terminal
F14
*1
F91*2
41 Ground Not existed
45
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM