2005 INFINITI FX35 ABS

EC-488
[VQ35DE]
DTC P1271, P1281 A/F SENSOR 1
Revision: 2005 July 2005 FX
DTC P1271, P1281 A/F SENSOR 1PFP:22693
Component DescriptionABS00A9T
The air fuel ratio (A/F) sensor is a planar dual-cell limit current sen-
sor. The sensor element of the air fuel ratio (A/F) sensor is the com-
bination 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 air fuel ratio (A/F) sen-
sor 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 temperature of 700 - 800 °C (1,292 - 1,472 °F).
CONSULT-II Reference Value in Data Monitor ModeABS00A9U
Specification data are reference values.
On Board Diagnosis LogicABS00A9V
To judge the malfunction, the diagnosis checks that the A/F signal computed by ECM from the air fuel ratio (A/
F) sensor 1 signal is not inordinately low.
DTC Confirmation ProcedureABS00A9W
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 11V 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 1.5V
DTC No. Trouble diagnosis name DTC detecting condition Possible Cause
P1271
1271
(Bank 1) Air fuel ratio (A/F) sensor 1
circuit no activity detected

The A/F signal computed by ECM from the
air fuel ratio (A/F) sensor 1 signal is con-
stantly approx. 0V.
Harness or connectors
(The air fuel ratio (A/F) sensor 1 cir-
cuit is open or shorted.)

Air fuel ratio (A/F) sensor 1
P1281
1281
(Bank 2)

EC-490
[VQ35DE]
DTC P1271, P1281 A/F SENSOR 1
Revision: 2005 July 2005 FX
Wiring DiagramABS00A9X
BANK 1
TBWM0390E

DTC P1271, P1281 A/F SENSOR 1 EC-493
[VQ35DE]
C
D E
F
G H
I
J
K L
M A
EC
Revision: 2005 July 2005 FX
Specification data are reference values and are measured between each terminal and ground.
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.
Diagnostic ProcedureABS00A9Y
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground three screws on the body. Refer to EC-170, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
TERMI-
NAL NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
57 G A/F sensor 1 (Bank 2) [Engine is running]

Warm-up condition

Idle speed Approximately 2.6V
58 Y Approximately 2.3V
76 P Approximately 3.1V
77 BR Approximately 2.3V
PBIB2625E

EC-496
[VQ35DE]
DTC P1271, P1281 A/F SENSOR 1
Revision: 2005 July 2005 FX
Removal and InstallationABS00A9Z
AIR FUEL RATIO (A/F) SENSOR 1
Refer to EM-26, "EXHAUST MANIFOLD AND THREE WAY CATALYST" .

DTC P1272, P1282 A/F SENSOR 1 EC-497
[VQ35DE]
C
D E
F
G H
I
J
K L
M A
EC
Revision: 2005 July 2005 FX
DTC P1272, P1282 A/F SENSOR 1PFP:22693
Component DescriptionABS00AA0
The air fuel ratio (A/F) sensor is a planar dual-cell limit current sen-
sor. The sensor element of the air fuel ratio (A/F) sensor is the com-
bination 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 air fuel ratio (A/F) sen-
sor 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 temperature of 700 - 800 °C (1,292 - 1,472 °F).
CONSULT-II Reference Value in Data Monitor ModeABS00AA1
Specification data are reference values.
On Board Diagnosis LogicABS00AA2
To judge the malfunction, the diagnosis checks that the A/F signal computed by ECM from the air fuel ratio (A/
F) sensor 1 signal is not inordinately high.
DTC Confirmation ProcedureABS00AA3
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 11V 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 1.5V
DTC No. Trouble diagnosis name DTC detecting condition Possible Cause
P1272
1272
(Bank 1) Air fuel ratio (A/F) sensor 1
circuit no activity detected

The A/F signal computed by ECM from the air
fuel ratio (A/F) sensor 1 signal is constantly
approx. 5V.
Harness or connectors
(The air fuel ratio (A/F) sensor 1 cir-
cuit is open or shorted.)

Air fuel ratio (A/F) sensor 1
P1282
1282
(Bank 2)

DTC P1272, P1282 A/F SENSOR 1 EC-499
[VQ35DE]
C
D E
F
G H
I
J
K L
M A
EC
Revision: 2005 July 2005 FX
Wiring DiagramABS00AA4
BANK 1
TBWM0390E

EC-502
[VQ35DE]
DTC P1272, P1282 A/F SENSOR 1
Revision: 2005 July 2005 FX
Specification data are reference values and are measured between each terminal and ground.
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.
Diagnostic ProcedureABS00AA5
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground three screws.Refer to EC-170, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
TERMI-
NAL NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
57 G A/F sensor 1 (Bank 2) [Engine is running]

Warm-up condition

Idle speed Approximately 2.6V
58 Y Approximately 2.3V
76 P Approximately 3.1V
77 BR Approximately 2.3V
PBIB2625E

DTC P1272, P1282 A/F SENSOR 1 EC-505
[VQ35DE]
C
D E
F
G H
I
J
K L
M A
EC
Revision: 2005 July 2005 FX
Removal and InstallationABS00AA6
AIR FUEL RATIO (A/F) SENSOR 1
Refer to EM-26, "EXHAUST MANIFOLD AND THREE WAY CATALYST" .