INFINITI QX56 2006 Factory Service Manual

EC-250Revision: November 2009
DTC P0133, P0153 A/F SENSOR 1
2006 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 ignition switch ON.
4. Check voltage between 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 E5, F14

IPDM E/R harness connector E119

10A fuse

Harness for open or short between A/F sensor 1 and fuse
>> Repair or replace harness or connectors.
Voltage: Battery voltage
BBIA0376E
PBIB1683E

DTC P0133, P0153 A/F SENSOR 1EC-251
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Revision: November 2009 2006 QX56
8. CHECK 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 A/F sensor 1 terminal and ECM terminal as follows. 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 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-162, "
Component Inspection" .
OK or NG
OK >> GO TO 10.
NG >> GO TO 13.
10. CHECK MASS AIR FLOW SENSOR
Refer to EC-178, "
Component Inspection" .
OK or NG
OK >> GO TO 11.
NG >> Replace mass air flow sensor.
A/F sensor 1 terminal ECM terminal
Bank1 11
6
27 5
53 5
65 6
Bank 2 17
6
27 7
55 7
65 8
Continuity should exist.
Bank 1 Bank 2
A/F sensor 1 terminal ECM terminal A/F sensor 1 terminal ECM terminal 11 617 6
27 527 7
53 555 7
65 665 8
Continuity should not exist.

EC-252Revision: November 2009
DTC P0133, P0153 A/F SENSOR 1
2006 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. CHECK INTERMITTENT INCIDENT
Perform EC-144, "
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 Oxygen Sen-
sor Thread Cleaner tool J-43897-18 or J-43897-12) and approved anti-seize lubricant.
>>INSPECTION END
Removal and InstallationUBS00N6X
AIR FUEL RATIO (A/F) SENSOR 1
Refer to EM-21, "EXHAUST MANIFOLD AND THREE WAY CATALYST" .

DTC P0137, P0157 HO2S2EC-253
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Revision: November 2009 2006 QX56
DTC P0137, P0157 HO2S2PFP:226A0
Component DescriptionUBS00H8B
The heated oxygen sensor 2, after three way catalyst (manifold),
monitors the oxygen level in the exhaust gas on each bank.
Even if switching characteristics of the air fuel ratio (A/F) sensor 1
are shifted, the air-fuel ratio is controlled to stoichiometric, by the sig-
nal from the heated oxygen sensor 2.
This sensor is made of ceramic zirconia. The zirconia generates volt-
age from approximately 1V in richer conditions to 0V in leaner condi-
tions.
Under normal conditions the heated oxygen sensor 2 is not used for
engine control operation.
CONSULT-II Reference Value in Data Monitor ModeUBS00ODQ
Specification data are reference values.
On Board Diagnosis LogicUBS00H8D
The heated oxygen sensor 2 has a much longer switching time
between rich and lean than the air fuel ratio (A/F) sensor 1. The oxy-
gen storage capacity of the three way catalyst (manifold) causes the
longer switching time. To judge the malfunctions of heated oxygen
sensor 2, ECM monitors whether the maximum voltage of the sensor
is sufficiently high during the various driving condition such as fuel-
cut.
SEF327R
MONITOR ITEMCONDITION SPECIFICATION
HO2S2 (B1)
HO2S2 (B2)

Revving engine from idle to 3,000 rpm quickly after the following condi-
tions are met.
–Engine: After warming up
–Keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and
at idle for 1 minute under no load 0 - 0.3V
←→ Approx. 0.6 -
1.0V
HO2S2 MNTR (B1)
HO2S2 MNTR (B2) LEAN
←→ RICH
PBIB1154E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0137
0137
(Bank 1) Heated oxygen sensor
2 circuit low voltage The maximum voltage from the sensor is not
reached to the specified voltage.

Harness or connectors
(The sensor circuit is open or shorted)

Heated oxygen sensor 2

Fuel pressure

Fuel injector

Intake air leaks
P0157
0157
(Bank 2)

EC-254Revision: November 2009
DTC P0137, P0157 HO2S2
2006 QX56
DTC Confirmation ProcedureUBS00H8E
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.
WITH CONSULT-II
TESTING CONDITION:
For better results, perform “DTC WORK SUPPORT” at a temperature of 0 to 30 °C (32 to 86 ° F).
1. Turn ignition switch ON and select “DATA MONITOR ” mode with
CONSULT-II.
2. Start engine and warm it up to the normal operating tempera- ture.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.
5. Let engine idle for 1 minute.
6. Make sure that “COOLAN TEMP/S ” indicates more than 70°C
(158 °F).
If not, warm up engine and go to next step when “COOLAN
TEMP/S ” indication reaches to 70 °C (158 °F).
7. Open engine hood.
8. Select “HO2S2 (B1) P1147 ” (for DTC P0137) or “HO2S2 (B2) P1167” (for DTC P0157) of “HO2S2” in
“DTC WORK SUPPORT ” mode with CONSULT-II.
9. Start engine and following the instruction of CONSULT-II.
NOTE:
It will take at most 10 minutes until “COMPLETED” is displayed.
10. Make sure that “OK ” is displayed after touching “SELF-DIAG RESULTS”.
If “NG ” is displayed, refer to EC-259, "
Diagnostic Procedure" .
If “CAN NOT BE DIAGNOSED ” is displayed, perform the following.
a. Turn ignition switch OFF and leave the vehicle in a cool place (soak the vehicle).
b. Return to step 1.
Overall Function CheckUBS00H8F
Use this procedure to check the overall function of the heated oxygen sensor 2 circuit. During this check, a 1st
trip DTC might not be confirmed.
WITH GST
1. Start engine and warm it up to the 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 1 minute under no load.
4. Let engine idle for 1 minute.
5. Set voltmeter probes between ECM terminal 55 [HO2S2 (B1) signal] or 74 [HO2S2 (B2) signal] and ground.
SEF174Y
PBIB2373E

DTC P0137, P0157 HO2S2EC-255
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Revision: November 2009 2006 QX56
6. Check the voltage when revving up to 4,000 rpm under no load
at least 10 times.
(Depress and release accelerator pedal as soon as possible.)
The voltage should be above 0.58V at least once during this
procedure.
If the voltage can be confirmed in step 6, step 7 is not nec-
essary.
7. Keep vehicle at idling for 10 minutes, then check the voltage. Or check the voltage when coasting from 80 km/h (50 MPH) in D
position.
The voltage should be above 0.58V at least once during this
procedure.
8. If NG, go to EC-259, "
Diagnostic Procedure" .
PBIB2054E

EC-256Revision: November 2009
DTC P0137, P0157 HO2S2
2006 QX56
Wiring DiagramUBS00H8G
BANK 1
BBWA1678E

DTC P0137, P0157 HO2S2EC-257
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Revision: November 2009 2006 QX56
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)
6GR Heated oxygen sensor 2
heater (bank 1) [Engine is running]

Engine speed: Below 3,600 rpm after the
following conditions are met.
–Engine: After warming up
–Keeping the engine speed between 3,500
and 4,000 rpm for 1 minute and at idle for 1
minute under no load
0 - 1.0V
[Ignition switch: ON]

Engine: Stopped
[Engine is running]

Engine speed: Above 3,600 rpm. BATTERY VOLTAGE
(11 - 14V)
55 R Heated oxygen sensor 2
(bank 1) [Engine is running]

Revving engine from idle to 3,000 rpm
quickly after the following conditions are
met.
–Engine: After warming up
–Keeping the engine speed between 3,500
and 4,000 rpm for 1 minute and at idle for 1
minute under no load
0 - Approximately 1.0V
78 B/W Sensor ground
(Heated oxygen sensor 2) [Engine is running]

Warm-up condition

Idle speed
Approximately 0V

EC-258Revision: November 2009
DTC P0137, P0157 HO2S2
2006 QX56
BANK 2
BBWA1679E

DTC P0137, P0157 HO2S2EC-259
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Revision: November 2009 2006 QX56
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 ProcedureUBS00H8H
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-150, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
TER-
MINAL NO. WIRE
COLOR ITEM
CONDITION DATA (DC Voltage)
25 O/G Heated oxygen sensor 2
heater (bank 2) [Engine is running]

Engine speed: Below 3,600 rpm after the
following conditions are met.
–Engine: After warming up
–Keeping the engine speed between 3,500
and 4,000 rpm for 1 minute and at idle for 1
minute under no load
0 - 1.0V
[Ignition switch: ON]

Engine: Stopped
[Engine is running]

Engine speed: Above 3,600 rpm. BATTERY VOLTAGE
(11 - 14V)
74 L Heated oxygen sensor 2
(bank 2) [Engine is running]

Revving engine from idle to 3,000 rpm
quickly after the following conditions are
met.
–Engine: After warming up
–Keeping the engine speed between 3,500
and 4,000 rpm for 1 minute and at idle for 1
minute under no load
0 - Approximately 1.0V
78 B/W Sensor ground
(Heated oxygen sensor 2) [Engine is running]

Warm-up condition

Idle speed
Approximately 0V
BBIA0354E