2006 INFINITI M35 engine

EC-318
[VQ35DE]
DTC P0139, P0159 HO2S2
Revision: 2006 January2006 M35/M45
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.
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-318, "
Component Inspection" .
OK or NG
OK >> GO TO 6.
NG >> Replace malfunctioning heated oxygen sensor 2.
6. CHECK INTERMITTENT INCIDENT
Refer to EC-165, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionNBS004XQ
HEATED OXYGEN SENSOR 2
With CONSULT-II
1. Turn ignition switch ON and select “DATA MONITOR” mode with
CONSULT-II.
2. Start engine and warm it up to the normal operating tempera-
ture.
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.
DTCTerminals
Bank
ECM Sensor
P0139 74 1 1
P0159 55 1 2
Continuity should exist.
DTCTerminals
Bank
ECM Sensor
P0139 74 1 1
P0159 55 1 2
Continuity should not exist.
SEF174Y

DTC P0139, P0159 HO2S2
EC-319
[VQ35DE]
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Revision: 2006 January2006 M35/M45
6. Select “FUEL INJECTION” in “ACTIVE TEST” mode, and select
“HO2S2 (B1)/(B2)” as the monitor item with CONSULT-II.
7. 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 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 oxygen sensor, clean exhaust system threads using Oxygen Sensor Thread
Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
Without CONSULT-II
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 74 [HO2S2 (B2) signal] or 55 [HO2S2 (B1) signal] and
ground.
6. Check the voltage when revving up to 4,000 rpm under no load
at least 10 times.
(Depress and release accelerator pedal as soon as possible.)
The voltage should be above 0.78V at least once during this
procedure.
If the voltage is above 0.78V at step 6, step 7 is not neces-
sary.
7. Keep vehicle at idling for 10 minutes, then check voltage. Or
check the voltage when coasting from 80 km/h (50 MPH) in D
position.
The voltage should be below 0.18V at least once during this
procedure.
8. If NG, replace 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 oxygen sensor, clean exhaust system threads using Oxygen Sensor Thread
Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
PBIB1672E
PBIB2163E
PBIB1607E

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-321
[VQ35DE]
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Revision: 2006 January2006 M35/M45
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTIONPFP:16600
On Board Diagnosis LogicNBS004XS
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 ProcedureNBS004XT
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-II
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-II.
4. Clear the self-learning control coefficient by touching “CLEAR”.
5. Select “DATA MONITOR” mode with CONSULT-II.
6. Start engine again and let it idle for at least 10 minutes.
The 1st trip DTC P0171 or P0174 should be detected at this
stage, if a malfunction exists. If so, go to EC-327, "
Diagnostic
Procedure" .
NOTE:
If 1st trip DTC is not detected during above procedure, perform-
ing 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 minutes. 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 1Density 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)
SEF968Y
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) conditionWhen 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).

EC-322
[VQ35DE]
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
Revision: 2006 January2006 M35/M45
7. If it is difficult to start engine at step 6, the fuel injection system has a malfunction, too.
8. Crank engine while depressing accelerator pedal. If engine starts, go to EC-327, "
Diagnostic Procedure" .
If engine does not start, check exhaust and intake air leak visually.
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 again and let it idle for at least 10 minutes.
9. Select Service $07 with GST. The 1st trip DTC P0171 or P0174
should be detected at this stage, if a malfunction exists. If so, go
to EC-327, "
Diagnostic 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.
10. If it is difficult to start engine at step 8, the fuel injection system has a malfunction.
11. Crank engine while depressing accelerator pedal. If engine starts, go to EC-327, "
Diagnostic Procedure" .
If engine does not start, check exhaust and intake air leak visually.
PBIB2783E
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) conditionWhen 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).

EC-324
[VQ35DE]
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
Revision: 2006 January2006 M35/M45
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-II.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECMs transistor. Use a ground other than ECM terminals, such as the ground.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.) TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
2SBA/F sensor 1 heater
(bank 1)[Engine is running]
Warm-up condition
Idle speedApproximately 5V
16 G/W
A/F sensor 1 (bank 1)[Engine is running]
Warm-up condition
Idle speedApproximately 3.1V
35 BR/WApproximately 2.6V
56 GApproximately 2.3V
75 GRApproximately 2.3V
21
22
23W
R/Y
R/BFuel injector No. 5
Fuel injector No. 3
Fuel injector No. 1[Engine is running]
Warm-up condition
Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idleBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
Warm-up condition
Engine speed: 2,000 rpmBATTERY VOLTAGE
(11 - 14V)
PBIB1584E
PBIB0042E
PBIB0043E

EC-326
[VQ35DE]
DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
Revision: 2006 January2006 M35/M45
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-II.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECMs transistor. Use a ground other than ECM terminals, such as the ground.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.) TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
24 OA/F sensor 1 heater
(bank 2)[Engine is running]
Warm-up condition
Idle speedApproximately 5V
40
41
42V/R
P/L
R/WFuel injector No. 6
Fuel injector No. 4
Fuel injector No. 2[Engine is running]
Warm-up condition
Idle speed
NOTE:
The pulse cycle changes depending on rpm
at idleBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
Warm-up condition
Engine speed: 2,000 rpmBATTERY VOLTAGE
(11 - 14V)
57 GR/L
A/F sensor 1 (bank 2)[Engine is running]
Warm-up condition
Idle speedApproximately 2.6V
58 LG/BApproximately 2.3V
76 W/LApproximately 3.1V
77 YApproximately 2.3V
PBIB1584E
PBIB0042E
PBIB0043E

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-327
[VQ35DE]
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Revision: 2006 January2006 M35/M45
Diagnostic ProcedureNBS004XV
1. CHECK EXHAUST GAS LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst 1.
OK or NG
OK >> GO TO 2.
NG >> Repair or replace.
2. CHECK FOR INTAKE AIR LEAK
1. Listen for an intake air leak after the mass air flow sensor.
2. Check PCV hose connection.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace.
PBIB1922E

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
EC-329
[VQ35DE]
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Revision: 2006 January2006 M35/M45
4. CHECK FUEL PRESSURE
1. Release fuel pressure to zero. Refer to EC-98, "
FUEL PRESSURE RELEASE" .
2. Install fuel pressure gauge and check fuel pressure. Refer to EC-98, "
FUEL PRESSURE CHECK" .
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5. DETECT MALFUNCTIONING PART
Check the following.
Fuel pump and circuit (Refer to EC-685, "FUEL PUMP" .)
Fuel pressure regulator (Refer to EC-98, "FUEL PRESSURE CHECK" .)
Fuel lines (Refer to FL-3, "FUEL SYSTEM" .)
Fuel filter for clogging
>> Repair or replace.
6. CHECK MASS AIR FLOW SENSOR
With CONSULT-II
1. Install all removed parts.
2. Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-II.
With GST
1. Install all removed parts.
2. Check mass air flow sensor signal in Service $01 with GST.
OK or NG
OK (With CONSULT-II)>>GO TO 7.
OK (Without CONSULT-II)>>GO TO 8.
NG >> Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or
grounds. Refer to EC-205, "
DTC P0101 MAF SENSOR" .
7. CHECK FUNCTION OF FUEL INJECTOR
With CONSULT-II
1. Start engine.
2. Perform “POWER BALANCE” in “ACTIVE TEST” mode with
CONSULT-II.
3. Make sure that each circuit produces a momentary engine
speed drop.
OK or NG
OK >> GO TO 10.
NG >> Perform trouble diagnosis for FUEL INJECTOR, refer to
EC-679, "
FUEL INJECTOR" . At idling: Approximately 350 kPa (3.57 kg/cm
2 , 51 psi)
2.0 - 6.0 gꞏm/sec: at idling
7.0 - 20.0 gꞏm/sec: at 2,500 rpm
2.0 - 6.0 gꞏm/sec: at idling
7.0 - 20.0 gꞏm/sec: at 2,500 rpm
PBIB0133E