Infiniti M35/M45 Y50. Manual - part 621

DTC P0131, P0151 A/F SENSOR 1

EC-957

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DTC P0131, P0151 A/F SENSOR 1

PFP:22693

Component Description

NBS005DX

The air fuel ratio (A/F) sensor 1 is a planar dual-cell limit current sen-
sor. The sensor element of the A/F sensor 1 is the combination of a
Nernst concentration cell (sensor cell) with an oxygen-pump cell,
which transports ions. It has a heater in the element.
The sensor is capable of precise measurement   = 1, but also in the
lean and rich range. Together with its control electronics, the sensor
outputs a clear, continuous signal throughout a wide   range (0.7 <

 < air).

The exhaust gas components diffuse through the diffusion gap at the
electrode of the oxygen pump and Nernst concentration cell, where
they are brought to thermodynamic balance.

An electronic circuit controls the pump current through the oxygen-
pump cell so that the composition of the exhaust gas in the diffusion
gap remains constant at   = 1. Therefore, the A/F sensor 1 is able to
indicate air/fuel ratio by this pumping of current. In addition, a heater
is integrated in the sensor to ensure the required operating tempera-
ture of 700 - 800

°

C (1,292 - 1,472

°

F).

CONSULT-II Reference Value in Data Monitor Mode

NBS005DY

Specification data are reference values.

On Board Diagnosis Logic

NBS005DZ

To judge the malfunction, the diagnosis checks that the A/F signal computed by ECM from the A/F sensor 1
signal is not inordinately low.

DTC Confirmation Procedure

NBS005E0

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.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 10.5V at idle.

 WITH CONSULT-II

1.

Start engine and warm it up to normal operating temperature.

2.

Select “A/F SEN1 (B1)” or “A/F SEN1 (B2)” in “DATA MONITOR” mode with CONSULT-II.

SEF579Z

SEF580Z

MONITOR ITEM

CONDITION

SPECIFICATION

A/F SEN1 (B1)
A/F SEN1 (B2)

●

Engine: After warming up

Maintaining engine speed at 2,000 rpm

Fluctuates around 1.5 V

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible Cause

P0131
0131
(Bank 1)

Air fuel ratio (A/F) sensor 1 
circuit low voltage

●

The A/F signal computed by ECM from the 
A/F sensor 1 signal is constantly approx. 0V.

●

Harness or connectors
(The A/F sensor 1 circuit is open or 
shorted.)

●

A/F sensor 1

P0151
0151
(Bank 2)

EC-958

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DTC P0131, P0151 A/F SENSOR 1

3.

Check “A/F SEN1 (B1)” or “A/F SEN1 (B2)” indication.
If the indication is constantly approx. 0V, go to 

EC-962, "Diag-

nostic Procedure"

 .

If the indication is not constantly approx. 0V, go to next step.

4.

Turn ignition switch OFF, wait at least 10 seconds and then
restart engine.

5.

Drive and accelerate vehicle to more than 40 km/h (25 MPH)
within 20 seconds after restarting engine.

6.

Maintain the following conditions for about 20 consecutive sec-
onds.

NOTE:

●

Keep the accelerator pedal as steady as possible during the cruising.

●

If this procedure is not completed within 1 minute after restarting engine at step 4, return to step
4.

7.

If 1st trip DTC is displayed, go to 

EC-962, "Diagnostic Procedure"

 .

 WITH GST

Follow the procedure “WITH CONSULT-II” above.

ENG SPEED

1,000 - 3,200 rpm

VHCL SPEED SE

More than 40 km/h (25 MPH)

B/FUEL SCHDL

1.5 - 9.0 msec

Gear position

Suitable position

SEF581Z

DTC P0131, P0151 A/F SENSOR 1

EC-959

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Wiring Diagram

NBS005E1

BANK 1

TBWT1046E

EC-960

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DTC P0131, P0151 A/F SENSOR 1

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 ECM's 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)

2

SB

A/F sensor 1 heater
(bank 1)

[Engine is running]

●

Warm-up condition

●

Idle speed

Approximately 5V

16

W/L

A/F sensor 1 (bank 1)

[Engine is running]

●

Warm-up condition

●

Idle speed

Approximately 3.1V

35

GR/L

Approximately 2.6V

56

LG/B

Approximately 2.3V

75

Y

Approximately 2.3V

PBIB1584E