Infiniti M45 (Y34). Manual - part 395

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

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BANK 2

TBWA0279E

EC-270

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

Diagnostic Procedure

ABS002HX

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

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.

SEC502D

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

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3. 

CHECK HEATED OXYGEN SENSOR 1 CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect corresponding heated oxygen sensor 1 (HO2S1) harness connector.

3.

Disconnect ECM harness connector.

4.

Check harness continuity between ECM terminal and HO2S1 terminal as follows.
Refer to Wiring Diagram.

5.

Check harness continuity between the following terminals and ground.
Refer to Wiring Diagram.

6.

Check harness continuity between HO2S1 terminal 4 and ground.

7.

Also check harness for short to power.

OK or NG

OK

>> GO TO 5.

NG

>> GO TO 4.

4. 

DETECT MALFUNCTIONING PART

Check the following.

●

Harness for open or short between ECM and HO2S1

●

Harness for open or short between HO2S1 and ground

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

5. 

CHECK FUEL PRESSURE

1.

Release fuel pressure to zero. Refer to 

EC-46, "FUEL PRESSURE RELEASE"

 .

2.

Install fuel pressure gauge and check fuel pressure. Refer to 

EC-48, "FUEL PRESSURE CHECK"

 .

OK or NG

OK

>> GO TO 7.

NG

>> GO TO 6.

DTC

Terminals

Bank

ECM

Sensor

P0171

114

1

1

P0174

115

1

2

Continuity should exist.

DTC

Terminals

Bank

ECM

Sensor

P0171

114

1

 1

P0174

115

1

 2

Continuity should not exist.

Continuity should exist.

At idling: 350 kPa (3.57 kg/cm

2

 , 51 psi)

EC-272

DTC P0171, P0174 FUEL INJECTION SYSTEM FUNCTION

6. 

DETECT MALFUNCTIONING PART

Check the following.

●

Fuel pump and circuit (Refer to 

EC-519

 , 

EC-674

 .)

●

Fuel pressure regulator (Refer to 

EC-48

 .)

●

Fuel lines (Refer to 

MA-14, "Checking Fuel Lines"

 .)

●

Fuel filter for clogging

>> Repair or replace.

7. 

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 MODE 1 with GST.

OK or NG

OK

>> GO TO 8.

NG

>> Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or

grounds. Refer to 

EC-174, "DTC P0101 MAF SENSOR"

 .

3.8 - 5.2 g·m/sec:

at idling

16.0 - 21.5 g·m/sec:

at 2,500 rpm

3.8 - 5.2 g·m/sec:

at idling

16.0 - 21.5 g·m/sec:

at 2,500 rpm