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Nissan Titan. Manual - part 234

P0139, P0159 HO2S2

EC-237

< DTC/CIRCUIT DIAGNOSIS >

[VK56DE]

3. Also check harness for short to power.
Is the inspection result normal?

YES

>> GO TO 5.

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

CHECK HEATED OXYGEN SENSOR 2

Refer to

EC-237, "Component Inspection"

Is the inspection result normal?

YES

>> GO TO 7.

>> GO TO 6.

REPLACE HEATED OXYGEN SENSOR 2

Replace malfunctioning heated oxygen sensor 2.

CAUTION:

• Discard any heated oxygen sensor which has been dropped from a height 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 heated oxygen sensor, clean exhaust system threads using Oxygen Sensor

Thread Cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved Anti-seize Lubri-

cant (commercial service tool).

>> INSPECTION END

CHECK INTERMITTENT INCIDENT

Refer to

GI-42, "Intermittent Incident"

>> INSPECTION END

Component Inspection

INFOID:0000000009886648

INSPECTION START

Do you have CONSULT?
Do you have CONSULT?

YES

>> GO TO 2.

>> GO TO 3.

CHECK HEATED OXYGEN SENSOR 2

With CONSULT

1. Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT.

2. Start engine and warm it up to the normal operating temperature.

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. Select “FUEL INJECTION” in “ACTIVE TEST” mode, and select “HO2S2 (B1)/(B2)” as the monitor item

with CONSULT.

7. Check “HO2S2 (B1) / (B2)” at idle speed when adjusting “FUEL INJECTION” to

±25%.

“HO2S2 (B1)/(B2)” should be above 0.70 V at least once when the “FUEL INJECTION” is +25%.

“HO2S2 (B1)/(B2)” should be below 0.18 V at least once when the “FUEL INJECTION” is

−25%.

Is the inspection result normal?

PBIB3458E

EC-238

< DTC/CIRCUIT DIAGNOSIS >

[VK56DE]

P0139, P0159 HO2S2

YES

>> INSPECTION END

>> GO TO 6.

CHECK HEATED OXYGEN SENSOR 2-I

Without CONSULT

1. Start engine and warm it up to the 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 terminals under the following condition.

Is the inspection result normal?

YES

>> INSPECTION END

>> GO TO 4.

CHECK HEATED OXYGEN SENSOR 2-II

Check the voltage between ECM harness connector terminals under the following condition.

Is the inspection result normal?

YES

>> INSPECTION END

>> GO TO 5.

CHECK HEATED OXYGEN SENSOR 2-III

Check the voltage between ECM harness connector terminals under the following condition.

Is the inspection result normal?

YES

>> INSPECTION END

>> GO TO 6.

ECM

Condition

Voltage

Connector

–

Terminal

F54

[HO2S2

(bank 1)]

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

The voltage should be above 0.70 V at least
once during this procedure.
The voltage should be below 0.18 V at least
once during this procedure.

[HO2S2

(bank 2)]

ECM

Condition

Voltage

Connector

–

Terminal

F54

[HO2S2

(bank 1)]

Keeping engine at idle for 10 minutes

The voltage should be above 0.70 V at least
once during this procedure.
The voltage should be below 0.18 V at least
once during this procedure.

[HO2S2

(bank 2)]

ECM

Condition

Voltage

Connector

–

Terminal

F54

[HO2S2

(bank 1)]

Coasting from 80 km/h (50 MPH) on the suit-
able gear position

The voltage should be above 0.70 V at least
once during this procedure.
The voltage should be below 0.18 V at least
once during this procedure.

[HO2S2

(bank 2)]

P0139, P0159 HO2S2

EC-239

< DTC/CIRCUIT DIAGNOSIS >

[VK56DE]

REPLACE HEATED OXYGEN SENSOR 2

Replace malfunctioning heated oxygen sensor 2.

CAUTION:

• Discard any heated oxygen sensor which has been dropped from a height 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 heated oxygen sensor, clean exhaust system threads using Oxygen Sensor

Thread Cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved Anti-seize Lubri-

cant (commercial service tool).

>> INSPECTION END

EC-240

< DTC/CIRCUIT DIAGNOSIS >

[VK56DE]

P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

On Board Diagnosis Logic

INFOID:0000000009886649

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 feedback signal from the A/F sensors 1. The ECM calcu-

lates the necessary compensation to correct the offset between the actual and the theoretical ratios.

In case the amount of the compensation value is extremely 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

INFOID:0000000009886650

NOTE:

If DTC Confirmation Procedure has been previously conducted, always perform the following before conduct-

ing the next step.
1. Turn ignition swich OFF and wait at least 10 seconds.
2. Turn ignition swich ON.
3. Turn ignition swich OFF and wait at least 10 seconds.

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 and select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CON-

SULT.

4. Clear the self-learning control coefficient by touching “CLEAR”.
5. Start engine again and let it idle for at least 10 minutes.
6. Check 1st trip DTC.

The 1st trip DTC P0171 or P0174 should be detected at this stage, if a malfunction exists. If so, go to

EC-

241, "Diagnosis Procedure"

NOTE:

If 1st trip DTC is not detected during above procedure, performing the following procedure is advised.

a. Turn ignition switch OFF and wait at least 10 seconds.
b. Start engine and drive the vehicle under the similar conditions to (1st trip) Freeze Frame Data for 10 min-

utes. Refer to the table below.

Hold the accelerator pedal as steady as possible.

The similar conditions to (1st trip) Freeze Frame Data means the vehicle operation that the following con-

ditions should be satisfied at the same time.

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.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0171
0171
(Bank 1)

Fuel injection system too
lean

• 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

P0174
0174
(Bank 2)

Engine speed

Engine speed in the freeze frame data

± 400 rpm

Vehicle speed

Vehicle speed in the freeze frame data

± 10 km/h (6 MPH)

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