Infiniti F50. Manual — part 409

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

EC-277

C

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EC

BANK 2

TBWM0152E

EC-278

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

Diagnostic Procedure

EBS00MCT

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

Listen for an intake air leak after the mass air flow sensor.

OK or NG

OK

>> GO TO 3.

NG

>> Repair or replace.

SEC502D

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

EC-279

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D

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EC

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 engine 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 engine 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-48, "FUEL PRESSURE RELEASE"

.

2.

Install fuel pressure gauge and check fuel pressure. Refer to

EC-49, "FUEL PRESSURE CHECK"

.

OK or NG

OK

>> GO TO 7.

NG

>> GO TO 6.

DTC

Terminals

Bank

ECM

Sensor

P0172

114

1

1

P0175

115

1

2

Continuity should exist.

DTC

Terminals

Bank

ECM

Sensor

P0172

114

1

1

P0175

115

1

2

Continuity should not exist.

Continuity should exist.

At idling: 350 kPa (3.57 kg/cm

2

, 51 psi)

EC-280

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

6.

DETECT MALFUNCTIONING PART

Check the following.

●

Fuel pump and circuit (Refer to

EC-513

,

EC-666

.)

●

Fuel pressure regulator (Refer to

EC-49

.)

>> 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

engine grounds. Refer to

EC-171, "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