2005 INFINITI QX4 Factory Service Manual

bolt pattern open hood fog light fuel additives check oil warning lights

Load previous 8 pages

Page 1705 of 3419

INFINITI QX4 2005 Factory Service Manual EC-514Revision: October 2005
DTC P1278, P1288 A/F SENSOR 1
2005 QX56
3. CHECK EXHAUST GAS LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst (manifold

Page 1706 of 3419

INFINITI QX4 2005 Factory Service Manual DTC P1278, P1288 A/F SENSOR 1
EC-515
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: October 20052005 QX56
5. CLEAR THE SELF-LEARNING DATA
With CONSULT-II
1. Start engine and warm it up to normal operating tempe

Page 1707 of 3419

INFINITI QX4 2005 Factory Service Manual EC-516Revision: October 2005
DTC P1278, P1288 A/F SENSOR 1
2005 QX56
6. CHECK A/F SENSOR 1 POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect A/F sensor 1 harness connector.
3. Turn ignit

Page 1708 of 3419

INFINITI QX4 2005 Factory Service Manual DTC P1278, P1288 A/F SENSOR 1
EC-517
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: October 20052005 QX56
8. CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect

Page 1709 of 3419

INFINITI QX4 2005 Factory Service Manual EC-518Revision: October 2005
DTC P1278, P1288 A/F SENSOR 1
2005 QX56
11 . CHECK PCV VALVE
Refer to EC-45, "
Component Inspection" .
OK or NG
OK >> GO TO 12.
NG >> Repair or replace PCV valve.
12. CHE

Page 1710 of 3419

INFINITI QX4 2005 Factory Service Manual DTC P1279, P1289 A/F SENSOR 1
EC-519
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: October 20052005 QX56
DTC P1279, P1289 A/F SENSOR 1PFP:22693
Component DescriptionUBS00HAM
The air fuel ratio (A/F) sensor 1 is

DTC P1279, P1289 A/F SENSOR 1
EC-519
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: October 20052005 QX56
DTC P1279, P1289 A/F SENSOR 1PFP:22693
Component DescriptionUBS00HAM
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 ModeUBS00HAN
Specification data are reference values.
On Board Diagnosis LogicUBS00HAO
To judge the malfunction of A/F sensor 1, this diagnosis measures response time of the A/F signal computed
by ECM from the A/F sensor 1 signal. The time is compensated by engine operating (speed and load), fuel
feedback control constant, and the A/F sensor 1 temperature index. Judgment is based on whether the com-
pensated time (the A/F signal cycling time index) is inordinately long or not.
SEF 5 79 Z
SEF 5 80 Z
MONITOR ITEM CONDITION SPECIFICATION
A/F SEN1 (B1)
A/F SEN1 (B2)
Engine: After warming upMaintaining engine speed at
2,000 rpmFluctuates 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 A/F sensor 1
signal takes more than the specified time.
Harness or connectors
(The A/F sensor 1 circuit 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)

Page 1711 of 3419

INFINITI QX4 2005 Factory Service Manual EC-520Revision: October 2005
DTC P1279, P1289 A/F SENSOR 1
2005 QX56
DTC Confirmation ProcedureUBS00HAP
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch O

EC-520Revision: October 2005
DTC P1279, P1289 A/F SENSOR 1
2005 QX56
DTC Confirmation ProcedureUBS00HAP
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-
146, "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-146, "
TROUBLE DIAGNOSIS - SPECIFICATION VALUE" .
10. Make sure that “OK” is displayed after touching “SELF-DIAG
RESULT”.
If “NG” is displayed, go to EC-525, "
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

Page 1712 of 3419

INFINITI QX4 2005 Factory Service Manual DTC P1279, P1289 A/F SENSOR 1
EC-521
C
D
E
F
G
H
I
J
K
L
MA
EC
Revision: October 20052005 QX56
Intake air leaks
Exhaust gas leaks
Incorrect fuel pressure
Lack of fuel
Fuel injector
Incorrect PCV

Load next 8 pages

Page: < prev 1-10 ... 1673-1680 1681-1688 1689-1696 1697-1704 1705-1712 1713-1720 1721-1728 1729-1736 1737-1744 ... 3424 next >

belt height adjustment fuel type jump start maintenance schedule spare wheel