INFINITI QX56 2006 Factory Service Manual

EC-580Revision: November 2009
DTC P2A00, P2A03 A/F SENSOR 1
2006 QX56
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.)
Diagnostic ProcedureUBS00N7I
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten two 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)
24 BR/W A/F sensor 1 heater
(bank 2) [Engine is running]

Warm-up condition

Idle speed Approximately 5V
57 L/P A/F sensor 1 (bank 2) [Engine is running]

Warm-up condition

Idle speed Approximately 2.6V
58 GR/G Approximately 2.3V
76 G/L Approximately 3.1V
77 BR/B Approximately 2.3V
PBIB1584E
BBIA0354E

DTC P2A00, P2A03 A/F SENSOR 1EC-581
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Revision: November 2009 2006 QX56
2. RETIGHTEN A/F SENSOR 1
1. Loosen and retighten the A/F sensor 1.
>> GO TO 3.
3. CHECK FOR INTAKE AIR LEAK
1. Start engine and run it at idle.
2. Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace. Tightening torque: 50 N-m (5.1 kg-m, 37 ft-lb)
BBIA0375E

EC-582Revision: November 2009
DTC P2A00, P2A03 A/F SENSOR 1
2006 QX56
4. CLEAR THE SELF-LEARNING DATA
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select “SELF-LEARNING CONT ” in “WORK SUPPORT ” mode with CONSULT-II.
3. Clear the self-learning control coefficient by touching “CLEAR”.
4. Run engine for at least 10 minutes at idle speed. Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected?
Is it difficult to start engine?
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF.
3. Disconnect mass air flow sensor harness connector.
4. Restart engine and let it idle for at least 5 seconds.
5. Stop engine and reconnect mass air flow sensor harness con- nector.
6. Make sure DTC P0102 is displayed.
7. Erase the DTC memory. Refer to EC-61, "
HOW TO ERASE
EMISSION-RELATED DIAGNOSTIC INFORMATION" .
8. Make sure DTC P0000 is displayed.
9. Run engine for at least 10 minutes at idle speed. Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected?
Is it difficult to start engine?
Ye s o r N o
Yes >> Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to EC-288, "DTC
P0171, P0174 FUEL INJECTION SYSTEM FUNCTION" or EC-299, "DTC P0172, P0175 FUEL
INJECTION SYSTEM FUNCTION" .
No >> GO TO 5.
SEF968Y
BBIA0368E

DTC P2A00, P2A03 A/F SENSOR 1EC-583
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Revision: November 2009 2006 QX56
5. CHECK HARNESS CONNECTOR
1. Turn ignition switch OFF.
2. Disconnect A/F sensor 1 harness connector.
3. Check harness connector for water.
OK or NG
OK >> GO TO 6.
NG >> Repair or replace harness connector.
6. CHECK A/F SENSOR 1 POWER SUPPLY CIRCUIT
1. Turn ignition switch ON.
2. 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.
Water should not exit.
BBIA0376E
Voltage: Battery voltage
PBIB1683E

EC-584Revision: November 2009
DTC P2A00, P2A03 A/F SENSOR 1
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 A/F SENSOR 1 HEATER
Refer to EC-162, "
Component Inspection" .
OK or NG
OK >> GO TO 10.
NG >> GO TO 11.
10. CHECK INTERMITTENT INCIDENT
Perform EC-144, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
OK or NG
OK >> GO TO 11.
NG >> Repair or replace.
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.

DTC P2A00, P2A03 A/F SENSOR 1EC-585
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Revision: November 2009 2006 QX56
11 . REPLACE AIR FUEL RATIO (A/F) SENSOR 1
Replace air fuel ratio (A/F) sensor 1.
CAUTION:

Discard any 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 A/F sensor, clean exhaust system threads using Oxygen Sensor Thread
Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
>>INSPECTION END
Removal and InstallationUBS00N7J
AIR FUEL RATIO (A/F) SENSOR 1
Refer to EM-21, "EXHAUST MANIFOLD AND THREE WAY CATALYST" .

EC-586Revision: November 2009
ASCD BRAKE SWITCH
2006 QX56
ASCD BRAKE SWITCHPFP:25320
Component DescriptionUBS00HDO
When the brake pedal is depressed, ASCD brake switch is turned
OFF and stop lamp switch is turned ON. ECM detects the state of
the brake pedal by this input of two kinds (ON/OFF signal).
Refer to EC-29, "
AUTOMATIC SPEED CONTROL DEVICE (ASCD)"
for the ASCD function.
CONSULT-II Reference Value in Data Monitor ModeUBS00HDP
Specification data are reference values.
BBIA0373E
MONITOR ITEM CONDITIONSPECIFICATION
BRAKE SW 1
(ASCD brake switch)

Ignition switch: ON
Brake pedal: Fully released ON

Brake pedal: Slightly depressedOFF
BRAKE SW 2
(Stop lamp switch)

Ignition switch: ON
Brake pedal: Fully released OFF

Brake pedal: Slightly depressed ON

ASCD BRAKE SWITCHEC-587
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Revision: November 2009 2006 QX56
Wiring DiagramUBS00HDQ
BBWA1716E

EC-588Revision: November 2009
ASCD BRAKE SWITCH
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 ProcedureUBS00HDR
1. CHECK OVERALL FUNCTION-I
With CONSULT-II
1. Turn ignition switch ON.
2. Select “BRAKE SW1 ” in “DATA MONITOR ” mode with CONSULT-II.
3. Check “BRAKE SW1 ” indication under the following conditions.
Without CONSULT-II
1. Turn ignition switch ON.
2. Check voltage between ECM terminal 108 and ground under the following conditions.
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
TER-
MINAL NO. WIRE
COLOR ITEM
CONDITION DATA (DC Voltage)
101 R/W Stop lamp switch [Ignition switch: OFF]

Brake pedal: Fully released
Approximately 0V
[Ignition switch: OFF]

Brake pedal: Slightly depressed BATTERY VOLTAGE
(11 - 14V)
108 BR/W ASCD brake switch [Ignition switch: ON]

Brake pedal: Slightly depressed
Approximately 0V
[Ignition switch: ON]

Brake pedal: Fully released BATTERY VOLTAGE
(11 - 14V)
CONDITION
INDICATION
Brake pedal: Slightly depressed OFF
Brake pedal: Fully released ON
SEC011D
CONDITIONVOLTAGE
Brake pedal: Slightly depressed Approximately 0V
Brake pedal: Fully released Battery voltage
MBIB0061E

ASCD BRAKE SWITCHEC-589
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Revision: November 2009 2006 QX56
2. CHECK OVERALL FUNCTION-II
With CONSULT-II
Check “BRAKE SW2 ” indication in “DATA MONITOR ” mode.
Without CONSULT-II
Check voltage between ECM terminal 101 and ground under the following conditions.
OK or NG
OK >> INSPECTION END
NG >> GO TO 7.
CONDITION INDICATION
Brake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
SEC013D
CONDITIONVOLTAGE
Brake pedal: Fully released Approximately 0V
Brake pedal: Slightly depressed Battery voltage
PBIB1537E