Infiniti M35/M45 Y50. Manual — part 463

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

EC-325

[VQ35DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

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

COLOR

ITEM

CONDITION

DATA (DC Voltage)

24

O

A/F sensor 1 heater
(bank 2)

[Engine is running]

●

Warm-up condition

●

Idle speed

Approximately 5V

40
41
42

V/R
P/L
R/W

Fuel 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 idle

BATTERY VOLTAGE

(11 - 14V)

[Engine is running]

●

Warm-up condition

●

Engine speed: 2,000 rpm

BATTERY VOLTAGE

(11 - 14V)

57

GR/L

A/F sensor 1 (bank 2)

[Engine is running]

●

Warm-up condition

●

Idle speed

Approximately 2.6V

58

LG/B

Approximately 2.3V

76

W/L

Approximately 3.1V

77

Y

Approximately 2.3V

PBIB1584E

PBIB0042E

PBIB0043E

EC-326

[VQ35DE]

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

Diagnostic Procedure

NBS004XZ

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

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

OK or NG

OK

>> GO TO 3.

NG

>> Repair or replace.

PBIB1922E

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

EC-327

[VQ35DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

3.

CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT

1.

Turn ignition switch OFF.

2.

Disconnect corresponding A/F sensor 1 harness connector.

3.

Disconnect ECM harness connector.

4.

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

5.

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

6.

Also check harness for 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.

A/F sensor 1 terminal

ECM terminal

Bank 1

1

16

2

75

5

35

6

56

Bank 2

1

76

2

77

5

57

6

58

Continuity should exist.

Bank 1

Bank 2

A/F sensor 1 terminal

ECM terminal

A/F sensor 1 terminal

ECM terminal

1

16

1

76

2

75

2

77

5

35

5

57

6

56

6

58

Continuity should not exist.

PBIB2794E

EC-328

[VQ35DE]

DTC P0172, P0175 FUEL INJECTION SYSTEM FUNCTION

4.

CHECK FUEL PRESSURE

1.

Release fuel pressure to zero. Refer to

EC-88, "FUEL PRESSURE RELEASE"

.

2.

Install fuel pressure gauge and check fuel pressure. Refer to

EC-89, "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-675, "FUEL PUMP"

.)

●

Fuel pressure regulator (Refer to

EC-89, "FUEL PRESSURE CHECK"

.)

>> 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-193, "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-669, "FUEL INJECTOR"

.

At idling: Approximately 350 kPa (3.57 kg/cm

2

, 51 psi)

2.0 - 6.0 g·m/sec:

at idling

7.0 - 20.0 g·m/sec:

at 2,500 rpm

2.0 - 6.0 g·m/sec:

at idling

7.0 - 20.0 g·m/sec:

at 2,500 rpm

PBIB0133E