2011 INFINITI QX56 fuse

COMPONENT PARTSEC-21
< SYSTEM DESCRIPTION > [VK56VD]
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Accelerator Pedal
Position SensorINFOID:0000000006217658
The accelerator pedal position (APP) sensor is installed on the
accelerator pedal assembly. The sensor detects the accelerator
position and sends a signal to the ECM.
Accelerator pedal position sensor has two sensors. These sensors
are a kind of potentiometer which transform the accelerator pedal
position into output voltage, and emit the voltage signals to the ECM.
The ECM judges the current opening angle of the accelerator pedal
from these signals and controls the throttle control motor based on
these signals.
Idle position of the accelerator pedal is determined by the ECM
receiving the signal from the accelerator pedal position sensor. The
ECM uses this signal for engine operations such as fuel cut.
Air Fuel Ratio (A/F) Sensor 1INFOID:0000000006217659
DESCRIPTION
The sensor element of the A/F sensor 1 is composed an electrode layer, 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 sens or outputs a clear, continuous signal throughout a wide range.
The exhaust gas components diffuse through the diffusion layer at the sensor cell. An electrode layer is
applied voltage, and this current relative oxygen density in lean. Also this current relative hydrocarbon density
in rich.
Therefore, the A/F sensor 1 is able to indicate air fuel ratio by this
electrode layer of current. In addition, a heater is integrated in the
sensor to ensure the required operating temperature of approxi-
mately 760 °C (1,400 °F).
A/F SENSOR 1 HEATER
A/F sensor 1 heater is integrated in the sensor.
The ECM performs ON/OFF duty control of the A/F sensor 1 heater corresponding to the engine operating
condition to keep the temperature of A/F s ensor 1 element within the specified range.
ASCD Brake Switch & Stop Lamp Switch INFOID:0000000006217660
Stop lamp switch and ASCD brake switch are installed to brake pedal bracket.
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 those two types of input (ON/OFF signal).
ASCD Steering SwitchINFOID:0000000006217661
ASCD steering switch has variant values of electrical resistance for each button. ECM reads voltage variation
of switch, and determines which button is operated.
ASCD IndicatorsINFOID:0000000006217662
ASCD operation status is indicated by CRUISE indicator in combination meter.
ECM transmits the ASCD status signal to the combi nation meter via CAN communication according to ASCD
operation.
PBIB1741E
JSBIA0527GB
Revision: 2010 May2011 QX56

FUEL PRESSUREEC-153
< BASIC INSPECTION > [VK56VD]
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FUEL PRESSURE
Work ProcedureINFOID:0000000006217756
FUEL PRESSURE RELEASE
WITH CONSULT-III
1. Turn ignition switch ON.
2. Perform “FUEL PRESSURE RELEASE” in
“WORK SUPPORT” mode with CONSULT-III.
3. Start engine.
4. After engine stalls, crank it two or three times to release all fuel pressure.
5. Turn ignition switch OFF.
WITHOUT CONSULT-III
1. Remove fuel pump fuse in IPDM E/R. NOTE:
 For the fuse number, refer to EC-114, "
Wiring Diagram".
 For the fuse arrangement, refer to PG-143, "
Fuse, Connector and Terminal Arrangement".
2. Start engine.
3. After engine stalls, crank it two or three times to release all fuel pressure.
4. Turn ignition switch OFF.
5. Reinstall fuel pump fuse after servicing fuel system.
LOW FUEL PRESSURE CHECK
CAUTION:
 Before disconnecting fuel line, release fuel pressure from fuel line to eliminate danger.
 The fuel hose connection method used when taking fuel pressure check must not be used for other
purposes.
 Do not perform fuel pressure check with electrical syst ems operating (i.e. lights, rear defogger, A/C,
etc.) Fuel pressure gauge may indicate false readin gs due to varying engine load and changes in
manifold vacuum.
NOTE:
Prepare pans or saucers under the disconnected fuel line because the fuel may spill out.
1. Release fuel pressure to zero.
2. Prepare fuel hose for fuel pressure check (B) and fuel tube adapter [SST (KV10118400)] (D), then connect fuel pressure
gauge (A).
CAUTION:
 Use suitable fuel hose for fuel pressure check (genuine
NISSAN fuel hose without quick connector).
 To avoid unnecessary force or tension to hose, use mod-
erately long fuel hose for fuel pressure check.
 Do not use the fuel hose for checking fuel pressure with damage or cracks on it.
 Use Pressure Gauge to check fuel pressure.
3. Disconnect fuel feed hose from fuel tube. Refer to EM-43, "
Exploded View".
CAUTION:
Do not twist or kink fuel hose because it is plastic hose.
To quick connector
To fuel tube (engine side)
C : Hose clamp
PBIB2982E
Revision: 2010 May2011 QX56

EC-168
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
POWER SUPPLY AND GROUND CIRCUIT
POWER SUPPLY AND GROUND CIRCUIT
Diagnosis ProcedureINFOID:0000000006217763
1.CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check the continuity between ECM harness connector and ground.
3. Also check harness for short to power.
Is the inspection result normal?
YES >> GO TO 3.
NO >> GO TO 2.
2.DETECT MALFUNCTIONING PART
Check the following.
 Loose or poor connection for each connector and harness
 Harness for open or short between ECM and ground
>> Repair open circuit or short to power in harness or connectors.
3.CHECK ECM POWER SUPPLY CIRCUIT-I
1. Reconnect ECM harness connector.
2. Turn ignition switch ON.
3. Check the voltage between ECM harness connector terminals.
Is the inspection result normal?
YES >> GO TO 5.
NO >> GO TO 4.
4.DETECT MALFUNCTIONING PART
Check the following.
 10 A fuse (No. 62)
 Loose or poor connection for each connector and harness
 Harness for open or short between ECM and fuse
>> Repair open circuit, short to ground or short to power in harness or connectors.
5.CHECK ECM POWER SUPPLY CIRCUIT-II
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Check the voltage between ECM harness connector terminals as per the following.
ECM Ground Continuity
Connector Terminal
F 111 1 0 Ground Existed
E80 174
175
ECM
Vo l ta g e
Connector +–
Terminal Terminal
E80 141 175 Battery voltage
Revision: 2010 May2011 QX56

EC-170
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
POWER SUPPLY AND GROUND CIRCUIT
Check the following.
 Loose or poor connection for each connector and harness
 Harness for open or short between ECM and IPDM E/R
>> Repair open circuit, short to ground or short to power in harness or connectors.
11 .CHECK 20 A FUSE
1. Disconnect 20 A fuse (No. 43) from IPDM E/R.
2. Check 20 A fuse.
Is the inspection result normal?
YES >> GO TO 14.
NO >> Replace 15 A fuse.
12.CHECK ECM POWER SUPPLY CIRCUIT-VI
1. Disconnect ECM harness connector.
2. Disconnect IPDM E/R harness connector.
3. Check the continuity between ECM harnes s connector and IPDM E/R harness connector.
4. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES >> GO TO 14.
NO >> GO TO 13.
13.DETECT MALFUNCTIONING PART
Check the following.
 Loose or poor connection for each connector and harness
 Harness for open or short between ECM and IPDM E/R
>> Repair open circuit, short to ground or short to power in harness or connectors.
14.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
Is the inspection result normal?
YES >> Replace IPDM E/R. Refer to PCS-32, "Removal and Installation".
NO >> Repair open circuit, short to ground or short to power in harness or connectors.
ECM IPDM E/R Continuity
Connector Terminal Connector Terminal
E80 171
E14 35 Existed
172
Revision: 2010 May2011 QX56

EC-182
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
P0031, P0032, P0051, P00
52 A/F SENSOR 1 HEATER
2.DETECT MALFUNCTIONING PART
Check the following.
 20 A fuse (No. 43)
 Harness for open or short between A/F sensor 1 and fuse
 Loose or poor connection for each connector and harness
>> Repair or replace harness or connectors.
3.CHECK A/F SENSOR 1 HEATER OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.
4. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES >> GO TO 4.
NO >> Repair open circuit, short to ground or short to power in harness or connectors.
4.CHECK A/F SENSOR 1 HEATER
Refer to EC-182, "
Component Inspection (A/F Sensor 1 Heater)".
Is the inspection result normal?
YES >> GO TO 6.
NO >> GO TO 5.
5.REPLACE A/F SENSOR 1
Replace malfunctioning A/F sensor 1. Refer to EM-40, "
Exploded View".
CAUTION:
 Discard any A/F sensor which has b een 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 exhau st system threads using Oxygen Sensor Thread
Cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved anti-seize lubricant
(commercial service tool).
>> INSPECTION END
6.CHECK INTERMITTENT INCIDENT
Perform GI-40, "
Intermittent Incident".
>> INSPECTION END
Component Inspection (A/F Sensor 1 Heater)INFOID:0000000006217777
1.CHECK AIR FUEL RATIO (A/F) SENSOR 1
1. Turn ignition switch OFF.
2. Disconnect air fuel ratio (A/F) sensor 1 harness connector.
3. Check resistance between A/F sensor 1 terminals as per the following.
DTC A/F sensor 1 ECM
Continuity
Bank Connector Terminal Connector Terminal
P0031, P0032 1 F67 2 F11048
Existed
P0051, P0052 2 F68 2 53
Terminal Resistance
2 and 5 2.0 - 3.2 Ω [at 25 °C (77 °F)]
Revision: 2010 May2011 QX56

P0037, P0038, P0057, P0058 HO2S2 HEATER
EC-185
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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Is the inspection result normal?
YES >> GO TO 3.
NO >> GO TO 2.
2.DETECT MALFUNCTIONING PART
Check the following.
 20 A fuse (No. 43)
 Harness for open or short between heated oxygen sensor 2 and fuse
 Loose or poor connection for each connector and harness
>> Repair open circuit, short to ground or short to power in harness or connectors.
3.CHECK HO2S2 OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between HO2S2 harness connector and ECM harness connector.
4. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES >> GO TO 4.
NO >> Repair open circuit, short to ground or short to power in harness or connectors.
4.CHECK HO2S2 HEATER
Refer to EC-186, "
Component Inspection (HO2 Sensor 2 Heater)".
Is the inspection result normal?
YES >> GO TO 6.
NO >> GO TO 5.
5.REPLACE HEATED OXYGEN SENSOR 2
Replace malfunctioning heated oxygen sensor 2. Refer to EX-5, "
Removal and Installation".
CAUTION:
 Discard any heated oxygen sensor which has been dr opped 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 oxygen sensor, clean exh aust system threads using Oxygen Sensor Thread
Cleaner [commercial service tool (J-43897-18 or J-43897-12)] and approved anti-seize lubricant
(commercial service tool).
>> INSPECTION END
6.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
DTC HO2S2
Ground Voltage
Bank Connector Terminal
P0037, P0038 1 F87 2 Ground Battery voltage
P0057, P0058 2 F88 2
DTC HO2S2 ECM
Continuity
Bank Connector Terminal Connector Terminal
P0037, P0038 1 F87 3 F 11147
Existed
P0057, P0058 2 F88 3 52
Revision: 2010 May2011 QX56

P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308 MISFIRE
EC-293
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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Stop engine and visually check exhaust tube, three way catalyst and muffler for dents.
Is the inspection result normal?
YES-1 >> With CONSULT-III: GO TO 3.
YES-2 >> Without CONSULT-III: GO TO 4.
NO >> Repair or replace malfunctioning part.
3.PERFORM POWER BALANCE TEST
WITH CONSULT-III
1. Start engine.
2. Perform “POWER BALANCE” in “A CTIVE TEST” mode with CONSULT-III.
3. Check that each circuit produces a momentary engine speed drop.
Is the inspection result normal?
YES >> GO TO 9.
NO >> GO TO 4.
4.CHECK FUNCTION OF FUEL INJECTOR-I
1. Start engine and let it idle.
2. Listen to each fuel injector operation.
Is the inspection result normal?
YES >> GO TO 5.
NO >> Perform trouble diagnosis for FUEL INJECTOR, refer to EC-498, "
Diagnosis Procedure".
5.CHECK FUNCTION OF IGNITION COIL-I
CAUTION:
Perform the following procedure in a place with no combustible objects and good ventilation.
1. Turn ignition switch OFF.
2. Remove fuel pump fuse No. in IPDM E/R to release fuel pressure. NOTE:
Do not use CONSULT-III to release fuel pressure, or fuel pressure applies again during the following pro-
cedure.
3. Start engine.
4. After engine stalls, crank it 2 or 3 times to release all fuel pressure.
5. Turn ignition switch OFF.
6. Remove all ignition coil harness connectors to avoid the electrical discharge from the ignition coils.
7. Remove ignition coil and spark plug of the cylinder to be checked.
8. Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
9. Connect spark plug and harness connector to ignition coil.
10. Fix ignition coil using a rope etc. with gap of 13 - 17 mm (0.52 - 0.66 in) between the edge of the spark plug and grounded metal
portion as shown in the figure.
11. Crank engine for approximately 3 seconds, and check whether spark is generated between the spark plug and the grounded
metal portion.
CAUTION:
 Never place the spark plug and the ignition coil within 50
cm (19.7 in) each other. Be careful not to get an electrical
shock while checking, becau se the electrical discharge
voltage becomes 20 kV or more.
 It might damage the ignition coil if the gap of more than 17 mm (0.66 in) is made.
NOTE:
Clicking sound should be heard.
PBIB3332E
Spark should be generated.
JMBIA0066GB
Revision: 2010 May2011 QX56

P0420, P0430 THREE WAY CATALYST FUNCTIONEC-309
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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Diagnosis ProcedureINFOID:0000000006217853
1.CHECK EXHAUST SYSTEM
Visually check exhaust tubes and muffler for dents.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Repair or replace malfunctioning part.
2.CHECK EXHAUST GAS LEAKAGE
1. Start engine and run it at idle.
2. Listen for an exhaust gas leakage before the three way catalyst (manifold).
Is exhaust gas leakage detected?
YES >> Repair or replace malfunctioning part.
NO >> GO TO 3.
3.CHECK INTAKE AIR LEAKAGE
Listen for an intake air leakage after the mass air flow sensor.
Is intake air leakage detected?
YES >> Repair or replace malfunctioning part.
NO >> GO TO 4.
4.CHECK IDLE SPEED AND IGNITION TIMING
Check idle speed and ignition timing.
For procedure, refer to EC-530, "
Inspection" and EC-531, "Inspection".
For specification, refer to EC-538, "
Idle Speed" and EC-538, "Ignition Timing".
Is the inspection result normal?
YES >> GO TO 5.
NO >> Follow the EC-139, "
Work Procedure".
5.CHECK FUEL INJECTORS
Refer to EC-498, "
Component Function Check".
Is the inspection result normal?
YES >> GO TO 6.
NO >> Perform EC-498, "
Diagnosis Procedure".
6.CHECK FUNCTION OF IGNITION COIL-I
CAUTION:
Perform the following procedure in a place with no combustible objects and good ventilation.
1. Turn ignition switch OFF.
2. Remove fuel pump fuse in IPDM E/R to release fuel pressure.
NOTE:
 For the fuse number, refer to EC-114, "
Wiring Diagram".
 For the fuse arrangement, refer to PG-140, "
Fuse, Connector and Terminal Arrangement".
 Do not use CONSULT-III to release fuel pressure, or fuel pressure applies again during the following
procedure.
3. Start engine.
4. After engine stalls, crank it 2 or 3 times to release all fuel pressure.
5. Turn ignition switch OFF.
PBIB1216E
Revision: 2010 May2011 QX56