Infiniti M45 (Y34). Manual - part 397

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

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Wiring Diagram

ABS002I0

BANK 1

TBWA0278E

EC-278

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

BANK 2

TBWA0279E

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

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Diagnostic Procedure

ABS002I1

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

EC-280

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

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

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)