2005 INFINITI FX35 sensor

DTC P1278, P1288 A/F SENSOR 1 EC-545
[VQ35DE]
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Revision: 2005 July 2005 FX
6. CHECK AIR FUEL RATIO (A/F) SENSOR 1 POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect air fuel ratio (A/F) sensor 1 harness connector.
3. Turn ignition switch ON.
4. Check voltage between air fuel ratio (A/F) sensor 1 terminal 3 and ground with CONSULT-II or tester.
OK or NG
OK >> GO TO 8.
NG >> GO TO 7.
7. DETECT MALFUNCTIONING PART
Check the following.

Harness connectors E18, F48

Fuse block (J/B) connector E201

10A fuse

Harness for open or short between air fuel ratio (A/F) sensor 1 and fuse
>> Repair or replace harness or connectors.
Voltage: Battery voltage
PBIB2190E
PBIB1683E

EC-546
[VQ35DE]
DTC P1278, P1288 A/F SENSOR 1
Revision: 2005 July 2005 FX
8. CHECK AIR FUEL RATIO (A/F) SENSOR 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between the following terminals. Refer to Wiring Diagram.
4. Check harness continuity between the following terminals and ground. Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 9.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
9. CHECK AIR FUEL RATIO (A/F) SENSOR 1 HEATER
Refer to EC-412, "
Component Inspection" .
OK or NG
OK >> GO TO 10.
NG >> Replace air fuel ratio (A/F) sensor 1.
10. CHECK MASS AIR FLOW SENSOR
Refer to EC-193, "
Component Inspection" .
OK or NG
OK >> GO TO 11.
NG >> Replace mass air flow sensor.
A/F sensor 1 terminal ECM terminal
Bank1 116
275
535
656
Bank 2 176
277
557
658
Continuity should exist.
Bank 1 Bank 2
A/F sensor 1 terminal ECM terminal A/F sensor 1 terminal ECM terminal 116176
275277
535557
656658
Continuity should not exist.

DTC P1278, P1288 A/F SENSOR 1 EC-547
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Revision: 2005 July 2005 FX
11 . CHECK PCV VALVE
Refer to EC-51, "
POSITIVE CRANKCASE VENTILATION" .
OK or NG
OK >> GO TO 12.
NG >> Repair or replace PCV valve.
12. CHECK INTERMITTENT INCIDENT
Perform EC-163, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
OK or NG
OK >> GO TO 13.
NG >> Repair or replace.
13. REPLACE AIR FUEL RATIO (A/F) SENSOR 1
Replace air fuel ratio (A/F) sensor 1.
CAUTION:

Discard any air fuel ratio (A/F) sensor which has been dropped from a height of more than 0.5 m
(19.7 in) onto a hard surface such as a concrete floor; use a new one.

Before installing new air fuel ratio (A/F) sensor, clean exhaust system threads using Heated Oxy-
gen Sensor Thread Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
>> INSPECTION END
Removal and InstallationABS00AAZ
AIR FUEL RATIO (A/F) SENSOR 1
Refer to EM-26, "EXHAUST MANIFOLD AND THREE WAY CATALYST" .

EC-548
[VQ35DE]
DTC P1279, P1289 A/F SENSOR 1
Revision: 2005 July 2005 FX
DTC P1279, P1289 A/F SENSOR 1PFP:22693
Component DescriptionABS00AB0
The air fuel ratio (A/F) sensor 1 is a planar dual-cell limit current sen-
sor. The sensor element of the air fuel ratio (A/F) sensor 1 is the
combination of a Nernst concentration cell (sensor cell) with an oxy-
gen-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 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 temperature of 700 - 800 °C (1,292 - 1,472 °F).
CONSULT-II Reference Value in Data Monitor ModeABS00AB1
Specification data are reference values.
On Board Diagnosis LogicABS00AB2
To judge the malfunction of air fuel ratio (A/F) sensor 1, this diagnosis measures response time of the A/F sig-
nal computed by ECM from the air fuel ratio (A/F) sensor 1 signal. The time is compensated by engine operat-
ing (speed and load), fuel feedback control constant, and the air fuel ratio (A/F) sensor 1 temperature index.
Judgment is based on whether the compensated time (the A/F signal cycling time index) is inordinately long or
not.
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
P1279
1279
(Bank 1)
Air fuel ratio (A/F) sensor 1
circuit slow response

The response (from LEAN to RICH) of the A/F
signal computed by ECM from air fuel ratio (A/
F) sensor 1 signal takes more than the speci-
fied time.

Harness or connectors
(The air fuel ratio (A/F) sensor 1 cir-
cuit is open or shorted.)

Air fuel ratio (A/F) sensor 1

Air fuel ratio (A/F) sensor 1 heater

Fuel pressure

Fuel Injector

Intake air leaks

Exhaust gas leaks

PCV

Mass air flow sensor
P1289
1289
(Bank 2)

DTC P1279, P1289 A/F SENSOR 1 EC-549
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Revision: 2005 July 2005 FX
DTC Confirmation ProcedureABS00AB3
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. Turn ignition switch OFF and wait at least 10 seconds.
3. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1minute under no load.
4. Let engine idle for 1 minute.
5. Select “A/F SEN1(B1) P1278/P1279” or “A/F SEN1(B1) P1288/P1289” of “A/F SEN1” in “DTC WORK SUPPORT” mode with CONSULT-II.
6. Touch “START”. If “COMPLETED” appears on CONSULT-II screen, go to step
10.
If “COMPLETED” does not appear on CONSULT-II screen, go to
the following step.
7. After perform the following procedure, “TESTING” will be dis- played on the CONSULT-II screen.
a. Increase the engine speed up to 4,000 to 5,000 rpm and keep it for 10 seconds.
b. Fully release accelerator pedal and then let engine idle for about 10 seconds.
If “TESTING” is not displayed after 10 seconds, refer to EC-
153, "TROUBLE DIAGNOSIS - SPECIFICATION VALUE" .
8. Wait for about 20 seconds at idle at under the condition that “TESTING” is displayed on the CONSULT-II screen.
9. Make sure that “TESTING” changes to “COMPLETED”. If “TESTING” changed to “OUT OF CONDITION”, refer to
EC-153, "
TROUBLE DIAGNOSIS - SPECIFICATION VALUE" .
10. Make sure that “OK” is displayed after touching “SELF-DIAG RESULT”.
If “NG” is displayed, go to EC-554, "
Diagnostic Procedure" .
WITH GST
1. Start engine and warm it up to normal operating temperature.
2. Select Service $01 with GST.
3. Calculate the total value of “Short term fuel trim” and “Long term fuel trim” indications. Make sure that the total percentage should be within ±15%.
If OK, go to the following step.
If NG, check the following.
PBIB0756E
PBIB1925E
PBIB0758E

EC-550
[VQ35DE]
DTC P1279, P1289 A/F SENSOR 1
Revision: 2005 July 2005 FX

Intake air leaks

Exhaust gas leaks

Incorrect fuel pressure

Lack of fuel

Fuel Injector

Incorrect PCV hose connection

PCV valve

Mass air flow sensor
4. Turn ignition switch OFF and wait at least 10 seconds.
5. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1minute under no load.
6. Let engine idle for 1 minute.
7. Increase the engine speed up to 4,000 to 5,000 rpm and keep it for 10 seconds.
8. Fully release accelerator pedal and then let engine idle for about 1 minute.
9. Select Service $07 with GST and make sure that no DTC is displayed. If the DTC is displayed, go to EC-554, "
Diagnostic Procedure" .

DTC P1279, P1289 A/F SENSOR 1 EC-551
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Revision: 2005 July 2005 FX
Wiring DiagramABS00AB4
BANK 1
TBWM0390E

EC-552
[VQ35DE]
DTC P1279, P1289 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.
TER-
MINAL
NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
16 G A/F sensor 1 (Bank 1) [Engine is running]

Warm-up condition

Idle speed Approximately 3.1V
35 B/R Approximately 2.6V
56 L Approximately 2.3V
75 R/B Approximately 2.3V