EC-274
< DTC/CIRCUIT DIAGNOSIS >[QR25DE]
P0138 HO2S2
P0138 HO2S2
DTC LogicINFOID:0000000009462224
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 capa city of the three way catalyst (manifold) 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.
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 FOR MALFUNCTION A
PBIB1848E
PBIB2376E
DTC No. CONSULT screen terms
(Trouble diagnosis content) DTC detecting condition Possible cause
P0138 HO2S2 (B1)
(O2 sensor circuit high voltage bank 1
sensor 2) A)
An excessively high voltage from
the sensor is sent to ECM. • Harness or connectors
(The sensor circuit is open or shorted)
• Heated oxygen sensor 2
B) The minimum voltage from the sen-
sor 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
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
EC-294
< DTC/CIRCUIT DIAGNOSIS >[QR25DE]
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
EC-296
< DTC/CIRCUIT DIAGNOSIS >[QR25DE]
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
EC-298
< DTC/CIRCUIT DIAGNOSIS >[QR25DE]
P0172 FUEL INJECTION SYSTEM FUNCTION
P0172 FUEL INJECTIO
N SYSTEM FUNCTION
DTC LogicINFOID:0000000009462236
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 rich.), 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-299, "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?
YES >> Proceed to EC-299, "Diagnosis Procedure".
NO >> GO TO 5.
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
P0172 FUEL SYS-RICH-B1
(System too rich bank 1) • Fuel injection system does not operate properly.
• The amount of mixture ratio compensation is too
large. (The mixture ratio is too rich.) • A/F sensor 1
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel pressure
• Mass air flow sensor
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
EC-300
< DTC/CIRCUIT DIAGNOSIS >[QR25DE]
P0172 FUEL INJECTION SYSTEM FUNCTION
*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-228, "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
1. Let engine idle.
+
−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
EC-318
< DTC/CIRCUIT DIAGNOSIS >[QR25DE]
P0300, P0301,
P0302, P0303, P0304 MISFIRE
P0300, P0301, P0302, P0303, P0304 MISFIRE
DTC LogicINFOID:0000000009462255
DTC DETECTION LOGIC
When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the crank-
shaft position (CKP) sensor (POS) signal to vary , ECM can determine that a misfire is occurring.
The misfire detection logic consists of the following two conditions.
1. One Trip Detection Logic (Three Way Catalyst Damage) On the 1st trip, when a misfire condition occurs that can damage the three way catalyst (TWC) due to
overheating, the MIL will blink.
When a misfire condition occurs, the ECM monitors the CKP sensor signal every 200 engine revolutions
for a change.
When the misfire condition decreases to a level that will not damage the TWC, the MIL will turn off.
If another misfire condition occurs that can dam age the TWC on a second trip, the MIL will blink.
When the misfire condition decreases to a level that will not damage the TWC, the MIL will remain on.
If another misfire condition occurs that can damage the TWC, the MIL will begin to blink again.
2. Two Trip Detection Logic (Exhaust quality deterioration) For misfire conditions that will not damage the TWC (but will affect vehicle emissions), the MIL will only
light when the misfire is detected on a second trip. Du ring this condition, the ECM monitors the CKP sen-
sor signal every 1,000 engine revolutions.
A misfire malfunction can be detected on any one cylinder or on multiple cylinders.
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. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Restart engine and let it idle for about 15 minutes.
4. Check 1st trip DTC.
Is 1st trip DTC detected?
YES >> Proceed to EC-319, "Diagnosis Procedure".
Sensor Input signal to ECM ECM function
Crankshaft position sensor (POS) Engine speed On board diagnosis of misfire
DTC No. CONSULT screen terms
(Trouble diagnosis content) DTC detecting condition Possible cause
P0300 MULTI CYL MISFIRE
(Random/multiple cylinder misfire detected) Multiple cylinder misfire.
• Improper spark plug
• Insufficient compression
• Incorrect fuel pressure
• Fuel Injector circuit is open or shorted
• Fuel injector
• Intake air leak
• Ignition signal circuit is open or shorted
• Lack of fuel
• Signal plate
• A/F sensor 1
• Incorrect PCV hose connection
P0301
CYL 1 MISFIRE
(Cylinder 1 Misfire Detected) No. 1 cylinder misfires.
P0302 CYL 2 MISFIRE
(Cylinder 2 Misfire Detected) No. 2 cylinder misfires.
P0303 CYL 3 MISFIRE
(Cylinder 3 Misfire Detected) No. 3 cylinder misfires.
P0304 CYL 4 MISFIRE
(Cylinder 4 Misfire Detected) No. 4 cylinder misfires.
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
EC-320
< DTC/CIRCUIT DIAGNOSIS >[QR25DE]
P0300, P0301,
P0302, P0303, P0304 MISFIRE
4.CHECK FUNCTION OF FUEL INJECTOR
1. Start engine and let engine idle.
2. Listen to each fuel injector operating sound.
Is the inspection result normal?
YES >> GO TO 5.
NO >> Perform trouble diagnosis for FUEL INJECTOR. Refer
to EC-505, "Diagnosis Procedure"
.
5.CHECK FUNCTION OF IGNITION COIL-1
CAUTION:
Do the following procedure in the place where ventilation is good without the combustible.
1. Turn ignition switch OFF.
2. Remove fuel pump fuse in IPDM E/R to release fuel pressure.
NOTE:
Do not use CONSULT to release fuel pressure, or fuel pressure applies again during the following proce-
dure.
3. Start engine.
4. After engine stalls, crank it two or three times to release all fuel pressure.
5. Turn ignition switch OFF.
6. Remove all ignition coil harness connectors to avoi d the electrical discharge from the ignition coils.
7. Remove ignition coil and spark plug of the cylinder to be checked.
8. Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
9. Connect spark plug and harness connector to ignition coil.
10. Fix ignition coil using a rope etc. with gap of 13 - 17 mm (0.52 - 0.66 in) between the edge of the spark plug and grounded metal
portion as shown in the figure.
11. Crank engine for about 3 seconds, and check whether spark is generated between the spark plug and the grounded metal por-
tion.
CAUTION:
• Do not approach to the spar k plug and the ignition coil
within 50 cm (19.7 in). Be car eful not to get an electrical
shock while checking, becau se the electrical discharge
voltage becomes 20 kV or more.
• It might cause to damage the igni tion coil if the gap of more than 17 mm (0.66 in) is taken.
NOTE:
When the gap is less than 13 mm (0.52 in), the sp ark might be generated even if the coil is mal-
functioning.
Is the inspection result normal?
YES >> GO TO 9.
NO >> GO TO 6.
6.CHECK FUNCTION OF IGNITION COIL-2
1. Turn ignition switch OFF.
2. Disconnect spark plug and connect a known-good spark plug.
3. Crank engine for about 3 seconds, and recheck whether spark is generated between the spark plug and the grounded metal portion.
Is the inspection result normal?
Clicking noise should be heard.
PBIB3332E
Spark should be generated.
JMBIA0066GB
Spark should be generated.
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM