2011 INFINITI QX56 ground

EC-510
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
IGNITION SIGNAL
3. 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-143, "
Fuse, Connector and Terminal Arrangement".
 Do not use CONSULT-III to release fuel pressure , or fuel pressure applies again during the following
procedure.
4. Start engine.
5. After engine stalls, crank it 2 or 3 times to release all fuel pressure.
6. Turn ignition switch OFF.
7. Remove all ignition coil harness connectors to avoi d the electrical discharge from the ignition coils.
8. Remove ignition coil and spark plug of the cylinder to be checked.
9. Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
10. Connect spark plug and harness connector to ignition coil.
11. 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.
12. 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:
When the gap is less than 13 mm (0.52 in), a spark might be generated even if the coil is malfunc-
tioning.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace malfunctioning ignition coil with power transistor.
Component Inspection (Condenser)INFOID:0000000006218014
1.CHECK CONDENSER
1. Turn ignition switch OFF.
2. Disconnect condenser harness connector.
3. Check resistance between condenser terminals as per the following.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace condenser. Spark should be generated.
JMBIA0066GB
Terminals Resistance
1 and 2 Above 1 M Ω [at 25 °C (77 °F)]
Revision: 2010 May2011 QX56

EC-512
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
LOW PRESSURE FUEL PUMP
LOW PRESSURE FUEL PUMP
Component Function CheckINFOID:0000000006218017
1.CHECK FUEL PUMP FUNCTION
1. Turn ignition switch ON.
2. Pinch fuel feed hose with two fingers. NOTE:
Fuel pressure pulsation should be felt on the fuel feed hose for 1 second after ignition switch is turned ON.
Is the inspection result normal?
YES >> INSPECTION END
NO >> EC-512, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000006218018
1.CHECK FPCM POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect FPCM harness connector.
3. Turn ignition switch ON.
4. Check the voltage between FPCM harness connector and ground.
Is the inspection result normal?
YES >> GO TO 2.
NO >> Perform the trouble diagnosis for power supply circuit. Refer to EC-168, "
Diagnosis Procedure".
2.CHECK FPCM GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Check the continuity between FPCM harness connector and ground.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repair open circuit or short to power in harness or connectors.
3.CHECK FPCM INPUT AND OUTPUT CIRCUIT
1. Disconnect ECM harness connector.
2. Check the continuity between FPCM harness connector and ECM harness connector.
3. Also check harness for short to ground and to power.
Is the inspection result normal?
+ −Voltag e
FPCM
Connector Terminal B41 10 Ground Battery voltage
+ −Continuity
FPCM
Connector Terminal B41 5 Ground Existed
+ −
Continuity
FPCM ECM
Connector Terminal Connector Terminal
B41 8
E80 125
Existed
9142
Revision: 2010 May2011 QX56

LOW PRESSURE FUEL PUMPEC-513
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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YES >> GO TO 4.
NO >> Repair or replace error-detected parts.
4.CHECK FUEL PUMP CONTROL CIRCUIT
1. Disconnect fuel level sensor unit and fuel pump harness connector.
2. Check the continuity between FPCM harness connecto r and fuel level sensor unit and fuel pump harness
connector.
3. Also check harness for short to ground and to power.
Is the inspection result normal?
YES >> GO TO 5.
NO >> Repair or replace error-detected parts.
5.CHECK LOW PRESSURE FUEL PUMP
Refer to EC-513, "
Component Inspection (Low Pressure Fuel Pump)".
Is the inspection result normal?
YES >> GO TO 6.
NO >> Replace fuel level sensor unit and fuel pump. Refer to FL-5, "
Removal and Installation".
6.CHECK FPCM
Refer to EC-514, "
Component Inspection (FPCM)".
Is the inspection result normal?
YES >> Check intermittent incident. Refer to GI-40, "Intermittent Incident".
NO >> Replace FPCM. Refer to EC-537, "
Removal and Installation".
Component Inspection (Low Pressure Fuel Pump)INFOID:0000000006218019
1.CHECK FUEL PRESSURE REGULATOR
1. Turn ignition switch OFF.
2. Check low fuel pressure. Refer to EC-153, "
Work Procedure".
Is inspection result normal?
YES >> INSPECTION END
NO >> GO TO 2.
2.CHECK LOW PRESSURE FUEL PUMP
1. Turn ignition switch OFF.
2. Disconnect fuel level sensor unit and fuel pump.
3. Check resistance between fuel level sens or unit and fuel pump terminals as follows.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace fuel level sensor unit and fuel pump. Refer to FL-5, "
Removal and Installation".
+−
Continuity
FPCM Fuel level sensor unit and fuel pump
Connector Terminal Connector Terminal
B41 6
C5 3
Existed
71
+ −
Condition Resistance
Fuel level sensor unit and fuel
pump
Te r m i n a l s
1 3 Temperature: 25 °C (77 °F) 0.2 - 5.0 Ω
Revision: 2010 May2011 QX56

EC-520
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
REFRIGERANT PRESSURE SENSOR
REFRIGERANT PRESSURE SENSOR
Component Function CheckINFOID:0000000006218026
1.CHECK REFRIGERANT PRESSURE SENSOR FUNCTION
1. Start engine and warm it up to normal operating temperature.
2. Turn A/C switch and blower fan switch ON.
3. Check the voltage between ECM harness connector terminals as per the following.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Go to EC-520, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000006218027
1.CHECK REFRIGERANT PRESSURE SENSOR POWER SUPPLY CIRCUIT
1. Disconnect refrigerant pressu re sensor harness connector.
2. Turn ignition switch ON.
3. Check the voltage between refrigerant pressure sensor harness connector and ground.
Is the inspection result normal?
YES >> GO TO 3.
NO >> GO TO 2.
2.DETECT MALFUNCTIONING PART
Check the following.
 Harness for open or short between ECM and refrigerant pressure sensor
 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 REFRIGERANT PRESSURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check the continuity between refrigerant pre ssure sensor harness connector and ECM harness connec-
tor.
4. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES >> GO TO 5.
NO >> GO TO 4.
ECM Voltage (V)
Connector +–
Terminal Terminal
E80 144
(Refrigerant pressure sensor signal) 150 1.0 - 4.0
Refrigerant pressure sensor
Ground Voltage (V)
Connector Terminal
E77 1 Ground Approx. 5
Refrigerant pressure sensor ECM Continuity
Connector Terminal Connector Terminal
E77 3 E80 150 Existed
Revision: 2010 May2011 QX56

REFRIGERANT PRESSURE SENSOREC-521
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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4.DETECT MALFUNCTIONING PART
Check the following.
 Harness for open or short between ECM and refrigerant pressure sensor
 Loose or poor connection for each connector and harness
>> Repair open circuit, short to ground or short to power in harness or connectors.
5.CHECK REFRIGERANT PRESSURE SENSOR IN PUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check the continuity between refrigerant pre ssure sensor harness connector and ECM harness connec-
tor.
2. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES >> GO TO 7.
NO >> GO TO 6.
6.DETECT MALFUNCTIONING PART
Check the following.
 Harness for open or short between ECM and refrigerant pressure sensor
 Loose or poor connection for each connector and harness
>> Repair open circuit, short to ground or short to power in harness or connectors.
7.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
Is the inspection result normal?
YES >> Replace refrigerant pressure sensor. Refer to HA-39, "REFRIGERANT PRESSURE SENSOR :
Removal and Installation".
NO >> Repair or replace malfunctioning part.
Refrigerant pressure sensor ECM Continuity
Connector Terminal Connector Terminal
E77 2 E80 144 Existed
Revision: 2010 May2011 QX56

EC-522
< DTC/CIRCUIT DIAGNOSIS >[VK56VD]
SNOW MODE SWITCH
SNOW MODE SWITCH
DescriptionINFOID:0000000006256403
The snow mode switch signal is sent to the combinat
ion meter from the snow mode switch. The combination
meter then sends the signal to the ECM via the CAN communication line.
The snow mode is used for driving or starting the vehicle on snowy roads or slippery areas. If the snow mode
is activated, the vehicle speed will not accelerate as quickly as normal to avoid vehicle slip. In other words,
ECM controls rapid engine torque change by controlling t he electric throttle control actuator operating speed.
Component Function CheckINFOID:0000000006256404
1.CHECK SNOW MODE SWITCH FUNCTION
1. Turn ignition switch ON.
2. Select “SNOW MODE SW” in “DATA MONITOR” mode with CONSULT-III.
3. Check “SNOW MODE SW” indication under the following conditions.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Go to EC-522, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000006256405
1.CHECK DTC WITH COMBINATION METER
Refer to MWI-30, "
CONSULT-III Function".
Is the inspection result normal?
YES >> GO TO 2.
NO >> Go to MWI-57, "
Work flow".
2.CHECK SNOW MODE SWITCH POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect snow mode switch harness connector.
3. Turn ignition switch ON.
4. Check the voltage between snow mode switch harness connector and ground.
Is the inspection result normal?
YES >> GO TO 4.
NO >> GO TO 3.
3.DETECT MALFUNCTIONING PART
Check the following.
 Fuse block harness connector M3
 10 A fuse (No. 13)
 Harness for open or short between snow mode switch and fuse.
>> Repair open circuit, short to ground or short to power in harness or connectors.
4.CHECK SNOW MODE SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
Monitor item Condition Indication
SNOW MODE SW Snow mode switch ON ON
OFF OFF
Snow mode switch
Ground Voltage
Connector Terminal
M54 12 Ground Battery voltage
Revision: 2010 May2011 QX56

SNOW MODE SWITCHEC-523
< DTC/CIRCUIT DIAGNOSIS > [VK56VD]
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2. Disconnect combination meter harness connector.
3. Check the continuity between snow mode switch
harness connector and combination meter harness con-
nector.
4. Also check harness for short to ground and short to power.
Is the inspection result normal?
YES >> GO TO 5.
NO >> Repair open circuit, short to ground or short to power in harness or connector.
5.CHECK SNOW MODE SWITCH
Refer to EC-523, "
Component Inspection".
Is the inspection result normal?
YES >> GO TO 6.
NO >> Replace snow mode switch. Refer to IP-25, "
Removal and Installation".
6.CHECK INTERMITTENT INCIDENT
Refer to GI-40, "
Intermittent Incident".
>> INSPECTION END
Component InspectionINFOID:0000000006256406
1.CHECK SNOW MODE SWITCH
1. Turn ignition switch OFF.
2. Disconnect snow mode s witch harness connector.
3. Check the continuity between snow mode s witch terminals under the following conditions.
Is the inspection result normal?
YES >> INSPECTION END
NO >> Replace snow mode switch. Refer to IP-25, "
Removal and Installation".
Snow mode switch Combination meter
Continuity
Connector Terminal Connector Terminal
M54 22 M34 33 Existed
Terminals Condition Continuity
12 and 22 Snow mode switch ON Existed
OFF Not Existed
Revision: 2010 May2011 QX56

EC-524
< SYMPTOM DIAGNOSIS >[VK56VD]
ENGINE CONTROL SYSTEM SYMPTOMS
SYMPTOM DIAGNOSIS
ENGINE CONTROL SYSTEM SYMPTOMS
Symptom TableINFOID:0000000006218028
SYSTEM — BASIC ENGINE CONTROL SYSTEM
SYMPTOM
Reference
page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
Fuel Low pressure fuel pump circuit 11232 22 3 2 EC-512
Low fuel pressure sensor circuit 4 4EC-483
Fuel pressure regulator system 334444444 4EC-198
Fuel injector circuit 11232 22 2EC-498
Evaporative emission system 334444444 4EC-532
FRP sensor circuit 11222 22 2EC-276EC-279
High pressure fuel pump circuit 4 3
EC-501
Air Positive crankcase ventilation sys-
tem 334444444 41
EC-534
Incorrect idle speed adjustment 1 1 1 1 1 EC-139
Electric throttle control actuator 112332222 2 2EC-460EC-466
IgnitionIncorrect ignition timing adjustment33111 11 1
EC-139
Ignition circuit 11222 22 2EC-506
Main power supply and ground circuit 22333 33 23 EC-168
Revision: 2010 May2011 QX56