2008 INFINITI FX35 engine

DTC P0139, P0159 HO2S2EC-855
< SERVICE INFORMATION > [VK45DE]
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COLOR ITEM CONDITION DATA (DC Voltage)
6R Heated oxygen sensor 2
heater (Bank 1) [Engine is running]
 Engine speed: Below 3,600 rpm after the fol-
lowing conditions are met
- Engine: After warming up
- Keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and at idle for 1
minute under no load 0 - 1.0V
[Ignition switch: ON]
 Engine stopped
[Engine is running]
 Engine speed: Above 3,600 rpm BATTERY VOLTAGE
(11 - 14V)
55 W/R Heated oxygen sensor 2
(Bank 1) [Engine is running]
 Revving engine from idle to 3,000 rpm quick-
ly after the following conditions are met
- Engine: After warming up
- After keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and at idle
for 1 minute under no load 0 - Approximately 1.0V
78 B/R Sensor ground
(Heated oxygen sensor 2) [Engine is running]

Warm-up condition
 Idle speed Approximately 0V
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

DTC P0139, P0159 HO2S2EC-857
< SERVICE INFORMATION > [VK45DE]
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Diagnosis ProcedureINFOID:0000000001326695
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-723, "
Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CLEAR THE SELF-LEARNING DATA
With CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Select “SELF-LEARNING CONT” in “W ORK SUPPORT” mode with CONSULT-III.
3. Clear the self-learning control coefficient by touching “CLEAR”.
4. 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?
Without CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF.
TER-
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NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
25 P Heated oxygen sensor 2
heater (Bank 2) [Engine is running]
 Engine speed: Below 3,600 rpm after the fol-
lowing conditions are met
- Engine: After warming up
- Keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and at idle for 1
minute under no load 0 - 1.0V
[Ignition switch: ON]
 Engine stopped
[Engine is running]
 Engine speed: Above 3,600 rpm BATTERY VOLTAGE
(11 - 14V)
74 LG/B Heated oxygen sensor 2
(Bank 2) [Engine is running]
 Revving engine from idle to 3,000 rpm quick-
ly after the following conditions are met
- Engine: After warming up
- After keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and at idle
for 1 minute under no load 0 - Approximately 1.0V
78 B/R Sensor ground
(Heated oxygen sensor 2) [Engine is running]

Warm-up condition
 Idle speed Approximately 0V
PBIB2195E
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

EC-858
< SERVICE INFORMATION >[VK45DE]
DTC P0139, P0159 HO2S2
3. Disconnect mass air flow sensor (1) harness connector, and
restart and run engine for at least 5 seconds at idle speed.
4. Stop engine and reconnect mass air flow sensor harness con-
nector.
5. Make sure DTC P0102 is displayed.
6. Erase the DTC memory. Refer to EC-633, "
Emission-related
Diagnostic Information".
7. Make sure DTC P0000 is displayed.
8. 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?
Ye s o r N o
Yes >> Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to EC-861 or EC-871.
No >> GO TO 3.
3.CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect heated oxygen sensor 2 harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between HO 2S2 terminal 4 and ECM terminal 78.
Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal and HO2S2 terminal as follows. Refer to Wiring Diagram.
2. Check harness continuity between the following terminals and ground. Refer to Wiring Diagram.
PBIB3230E
Continuity should exist.
PBIB1534E
DTC Te r m i n a l s
Bank
ECM Sensor
P0139 55 1 1
P0159 74 1 2
Continuity should exist.
DTC Te r m i n a l s
Bank
ECM Sensor
P0139 55 1 1
P0159 74 1 2
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

DTC P0139, P0159 HO2S2EC-859
< SERVICE INFORMATION > [VK45DE]
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3. Also check harness for short to power.
OK or NG
OK >> GO TO 5.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
5.CHECK HEATED OXYGEN SENSOR 2
Refer to EC-859, "
Component Inspection".
OK or NG
OK >> GO TO 6.
NG >> Replace malfunctioning heated oxygen sensor 2.
6.CHECK INTERMITTENT INCIDENT
Refer to EC-717
.
>> INSPECTION END
Component InspectionINFOID:0000000001326696
HEATED OXYGEN SENSOR 2
With CONSULT-III
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. Select “FUEL INJECTION” in “A CTIVE TEST” mode with CONSULT-III, and select “HO2S2 (B1)/(B2)” as
the monitor item.
6. Check “HO2S2 (B1)/(B2)” at idle speed when adjusting “FUEL INJECTION” to ±25%.
“HO2S2 (B1)/(B2)” should be above 0.78V at least once when the “FUEL INJECTION” is +25%.
“HO2S2 (B1)/(B2)” should be below 0.18V at least once when the “FUEL INJECTION” is −25%.
CAUTION:
 Discard any heated oxygen sensor which has been dr opped 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 oxygen sensor, clean exh aust system threads using Oxygen Sensor Thread
Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
Without CONSULT-III
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. Set voltmeter probes between ECM terminal 55 [HO2S2 (B1) signal] or 74 [HO2S2 (B2) signal] and ground.Continuity should not exist.
JMBIA0640GB
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DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-861
< SERVICE INFORMATION > [VK45DE]
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DTC P0171, P0174 FUEL IN
JECTION SYSTEM FUNCTION
On Board Diagnosis LogicINFOID:0000000001326698
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 air fuel ratio (A/F) sensor 1. The
ECM calculates the necessary compensation to corre ct the offset 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 ProcedureINFOID:0000000001326699
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-III
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-III.
4. Clear the self-learning control coefficient by touching “CLEAR”.
5. Start engine. If it is difficult to start engine, t he fuel injection system has a malfunction.
Perform the following procedure is advised.
a. Crank engine while depressing accelerator pedal.
b. If engine starts, go to EC-866, "
Diagnosis Procedure".
If engine does not start, check exhaust and intake air leak visually.
6. Keep engine at idle for at least 10 minutes.
7. Check 1st trip DTC.
8. If 1st trip DTC is detected, go to EC-866, "
Diagnosis Procedure".
If 1st trip DTC is not detected, per forming 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 condi tions 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 Da ta 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)
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EC-862
< SERVICE INFORMATION >[VK45DE]
DTC P0171, P0174 FUEL IN
JECTION SYSTEM FUNCTION
9. Check 1st trip DTC.
10. The 1st trip is detected, go to EC-866, "
Diagnosis Procedure".
WITH GST
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF and wait at least 10 seconds.
3. Disconnect mass air flow sensor (1) harness connector.
4. Restart engine and let it idle for at least 5 seconds.
5. Stop engine and reconnect mass air flow sensor harness con-
nector.
6. Select Service $03 with GST. Make sure DTC P0102 is detected.
7. Select Service $04 with GST and erase the DTC P0102.
8. Start engine. If it is difficult to start engine, the fuel injection system has a mal-
function.
Perform the following procedure is advised.
a. Crank engine while depressing accelerator pedal.
b. If engine starts, go to EC-866, "
Diagnosis Procedure".
If engine does not start, check exhaus t and intake air leak visually.
9. Keep engine at idle for at least 10 minutes.
10. Check 1st trip DTC.
11. If 1st trip DTC is detected, go to EC-866, "
Diagnosis Procedure".
If 1st trip DTC is not detected, per forming 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 Da ta means the vehicle operation that the following con-
ditions should be satisfied at the same time.
12. Check 1st trip DTC.
13. The 1st trip is detected, go to EC-866, "
Diagnosis Procedure".
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)
Engine coolant temperature (T)
condition When the freeze frame data shows lower than 70
°C (158 °F),
T should be lower than 70 °C (158 °F).
When the freeze frame data shows higher than or equal to 70 °C (158 °F),
T should be higher than or equal to 70 °C (158 °F).
PBIB3230E
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)
Engine coolant temperature (T)
condition When the freeze frame data shows lower than 70
°C (158 °F),
T should be lower than 70 °C (158 °F).
When the freeze frame data shows higher than or equal to 70 °C (158 °F),
T should be higher than or equal to 70 °C (158 °F).
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
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EC-864
< SERVICE INFORMATION >[VK45DE]
DTC P0171, P0174 FUEL IN
JECTION SYSTEM FUNCTION
Do not use ECM ground terminals when measuring in put/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground ot her than ECM terminals, such as the ground.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)TER-
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COLOR ITEM CONDITION DATA (DC Voltage)
2P A/F sensor 1 heater
(Bank 1) [Engine is running]

Warm-up condition
 Idle speed Approximately 5V
16 R A/F sensor 1 (Bank 1) [Engine is running]

Warm-up condition
 Idle speed Approximately 3.1V
35 G Approximately 2.6V
56 B Approximately 2.3V
75 OR Approximately 2.3V
21
22
23
44 W
R
P
OR Fuel injector No. 5
Fuel injector No. 3
Fuel injector No. 1
Fuel injector No. 7 [Engine is running]

Warm-up condition
 Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idle BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
 Warm-up condition
 Engine speed: 2,000 rpm BATTERY VOLTAGE
(11 - 14V)
PBIB1584E
PBIB0042E
PBIB0043E
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3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

EC-866
< SERVICE INFORMATION >[VK45DE]
DTC P0171, P0174 FUEL IN
JECTION SYSTEM FUNCTION
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnosis ProcedureINFOID:0000000001326701
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).
OK or NG
OK >> GO TO 2.
NG >> Repair or replace.
2.CHECK FOR INTAKE AIR LEAK
TER- MI-
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COLOR ITEM CONDITION DATA (DC Voltage)
24 P A/F sensor 1 heater
(Bank 2) [Engine is running]

Warm-up condition
 Idle speed Approximately 5V
40
41
42
63 PU
BR
B
G Fuel injector No. 6
Fuel injector No. 4
Fuel injector No. 2
Fuel injector No. 8 [Engine is running]

Warm-up condition
 Idle speed NOTE:
The pulse cycle changes depending on rpm
at idle BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
 Warm-up condition
 Engine speed: 2,000 rpm BATTERY VOLTAGE
(11 - 14V)
57 G A/F sensor 1 (Bank 2) [Engine is running]

Warm-up condition
 Idle speed Approximately 2.6V
58 L Approximately 2.3V
76 R Approximately 3.1V
77 OR Approximately 2.3V
PBIB1584E
PBIB0042E
PBIB0043E
PBIB1216E
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