INFINITI QX56 2009 Factory Service Manual

EC-474
< ECU DIAGNOSIS >[VK56DE]
ECM
1. If the ignition switch stays ON after repair work, be sure to turn ignition switch OFF once. Wait at least 10
seconds and then turn it ON (engine stopped) again.
2. Perform TM-30, "OBD-II Diagnostic Trouble Code (DTC)"
. (The DTC in TCM will be erased)
3. Select Service $04 with GST (Generic Scan Tool).
No Tools
NOTE:
If the DTC is not for AT related items (see EC-456, "DTC Index"
), skip step 2.
1. If the ignition switch stays ON after repair work, be sure to turn ignition switch OFF once.
Wait at least 10 seconds and then turn it ON (engine stopped) again.
2. Perform TM-30, "OBD-II Diagnostic Trouble Code (DTC)"
. (The DTC in the TCM will be erased.)
3. Change the diagnostic test mode from Mode II to Mode I by depressing the accelerator pedal. Refer to
EC-55, "Malfunction Indicator Lamp (MIL)"
.
 If the battery is disconnected, the emission-related diagnostic information will be lost within 24
hours.
 The following data are cleared when the ECM memory is erased.
- Diagnostic trouble codes
- 1st trip diagnostic trouble codes
- Freeze frame data
- 1st trip freeze frame data
- System readiness test (SRT) codes
- Test values
Actual work procedures are explained using a DTC as an ex ample. Be careful so that not only the DTC, but all
of the data listed above, are cleared from the ECM memory during work procedures.
Revision: December 20092009 QX56

ENGINE CONTROL SYSTEM SYMPTOMSEC-475
< SYMPTOM DIAGNOSIS > [VK56DE]
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SYMPTOM DIAGNOSIS
ENGINE CONTROL SYSTEM SYMPTOMS
Symptom Matrix ChartINFOID:0000000003771739
SYSTEM — BASIC ENGINE CONTROL SYSTEM
SYMPTOM
Refer-
ence 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 Fuel pump circuit 11232 22 3 2 EC-395
Fuel pressure regulator system 334444444 4EC-487
Injector circuit 11232 22 2EC-392
Evaporative emission system 334444444 4EC-37
Air Positive crankcase ventilation sys-
tem 334444444 41
EC-414
Incorrect idle speed adjustment 1 1 1 1 1 EC-13
Electric throttle control actuator 112332222 2 2EC-351
,
EC-354
,
EC-358
,
EC-360
IgnitionIncorrect ignition timing adjustment 33111 11 1 EC-13
Ignition circuit 11222 22 2EC-404
Main power supply and ground circuit 22333 33 23 EC-82
Revision: December 20092009 QX56

EC-476
< SYMPTOM DIAGNOSIS >[VK56DE]
ENGINE CONTROL SYSTEM SYMPTOMS
1 - 6: The numbers refer to the order of inspection.
(continued on next page)
SYSTEM — ENGINE MECHANICAL & OTHER
Mass air flow sensor circuit
1
12 2
222 2 EC-103,
EC-109
Engine coolant temperature sensor circuit
333
EC-120,
EC-128
Air fuel ratio (A/F ) sensor 1 circuit EC-136
,
EC-140
,
EC-143
,
EC-146
,
EC-377

Throttle position sensor circuit 22EC-124
,
EC-185
,
EC-302
,
EC-304
,
EC-369
Accelerator pedal position sensor circuit 3 2 1 EC-280
,
EC-362
,
EC-365
,
EC-373
Knock sensor circuit 2 3 EC-195
Crankshaft position sensor (POS) circuit 2 2EC-198
Camshaft position sensor (PHASE) circuit 3 2 EC-202
Vehicle speed signal circuit 2 3 3 3 EC-271
Power steering pressure sensor circuit 2 3 3 EC-277
ECM 22333333333 EC-280,
EC-282
Intake valve timing control solenoid valve cir-
cuit 32 13223 3
EC-100
Transmission range signal circuit 3 3 3 3 3 EC-288
Refrigerant pressure sensor circuit 2 3 3 4EC-416
Electrical load signal circuit 3EC-390
Air conditioner circuit 223333333 3 2HAC-25
ABS actuator and electric unit (control unit) 4 BRC-37
SYMPTOM
Refer-
ence 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
Revision: December 20092009 QX56

ENGINE CONTROL SYSTEM SYMPTOMSEC-477
< SYMPTOM DIAGNOSIS > [VK56DE]
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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 Fuel tank 5
5 FL-11
Fuel piping 5 5 5 5 5 5
FL-6
Va p o r l o c k —
Valve deposit 5 555 55 5 —
Poor fuel (Heavy weight gasoline,
Low octane) —
Air Air duct
55555 5 EM-25
Air cleaner
EM-25
Air leakage from air duct
(Mass air flow sensor — electric
throttle control actuator)
5555 EM-25
Electric throttle control actuator
EM-26
Air leakage from intake manifold/
Collector/GasketEM-26
Cranking Battery
111111
11
PG-77
Generator circuit
CHG-6
Starter circuit 3STR-8
Signal plate 6EM-45
Transmission range signal 4TM-44
Engine Cylinder head
55555 55 5 EM-68
Cylinder head gasket 4 3
Cylinder block
66666 66 6 4
EM-83
Piston
Piston ring
Connecting rod
Bearing
Crankshaft
Va l v e
mecha-
nism Timing chain
55555 55 5 EM-45
Camshaft
EM-53
Intake valve timing controlEM-53
Intake valve
3EM-68
Exhaust valve
Revision: December 20092009 QX56

EC-478
< SYMPTOM DIAGNOSIS >[VK56DE]
ENGINE CONTROL SYSTEM SYMPTOMS
1 - 6: The numbers refer to the order of inspection.Exhaust Exhaust manifold/Tube/Muffler/
Gasket 55555 55 5 EM-30
,
EX-
5Three way catalyst
Lubrica-
tion Oil pan/Oil strainer/Oil pump/Oil
filter/Oil gallery/Oil cooler
55555 55 5 EM-33
,
LU-
14 , LU-11 ,
LU-12
Oil level (Low)/Filthy oil LU-8, "In-spection"
Cooling Radiator/Hose/Radiator filler cap
55555 55 45 CO-15
Thermostat 5
CO-22
Water pumpCO-20
Water galleryCO-6
Cooling fan 5CO-18,
CO-
19
Coolant level (Low)/Contaminat-
ed coolant 5
CO-10
IVIS (INFINITI Vehicle Immobilizer System —
NATS) 11
SEC-6
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
Revision: December 20092009 QX56

NORMAL OPERATING CONDITIONEC-479
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NORMAL OPERATING CONDITION
Fuel Cut Control (at No
Load and High Engine Speed)INFOID:0000000003771740
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM through CAN communication line.
SYSTEM DESCRIPTION
If the engine speed is above 1,800 rpm under no load (for example, the shift position is neutral and engine
speed over is 1,800 rpm) fuel will be cut off after some time. The exact time when the fuel is cut off varies
based on engine speed.
Fuel cut will be operated until the engine speed reaches 1,500 rpm, then fuel cut will be cancelled.
NOTE:
This function is different from deceleration control listed under EC-28, "System Description"
.
Sensor Input signal to ECM ECM function Actuator
TCM Neutral position
Fuel cut control Fuel injector
Accelerator pedal position sensor Accelerator pedal position
Engine coolant temperature sensor Engine coolant temperature
Crankshaft position sensor (POS)
Camshaft position sensor (PHASE)
Engine speed
Wheel sensor Vehicle speed*
Revision: December 20092009 QX56

EC-480
< PRECAUTION >[VK56DE]
PRECAUTIONS
PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint S
ystem (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000005867525
The Supplemental Restraint System such as “A IR BAG” and “SEAT BELT PRE-TENSIONER”, used along
with a front seat belt, helps to reduce the risk or severi ty of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and w hether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SR and SB section of this Service Man-
ual.
WARNING:
 To avoid rendering the SRS inopera tive, which could increase the risk of personal injury or death in
the event of a collision which would result in air bag inflation, all maintenance must be performed by
an authorized NISS AN/INFINITI dealer.
 Improper maintenance, including in correct removal and installation of the SRS, can lead to personal
injury caused by unintent ional activation of the system. For re moval of Spiral Cable and Air Bag
Module, see the SR section.
 Do not use electrical test equipmen t on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identi fied by yellow and/or orange harnesses or har-
ness connectors.
PRECAUTIONS WHEN USING POWER TOOLS (AIR OR ELECTRIC) AND HAMMERS
WARNING:
 When working near the Airbag Diagnosis Sensor Unit or other Airbag System sensors with the Igni-
tion ON or engine running, DO NOT use air or electri c power tools or strike near the sensor(s) with a
hammer. Heavy vibration could activate the sensor( s) and deploy the air bag(s), possibly causing
serious injury.
 When using air or electric power tools or hammers , always switch the Ignition OFF, disconnect the
battery, and wait at least 3 minu tes before performing any service.
On Board Diagnosis (OBD) System of Engine and A/TINFOID:0000000003771742
The ECM has an on board diagnostic system. It will light up the malfunction indicator lamp (MIL) to warn the
driver of a malfunction causing emission deterioration.
CAUTION:
 Be sure to turn the ignition sw itch OFF and disconnect the negative battery cable before any repair
or inspection work. The open/short circuit of re lated switches, sensors, solenoid valves, etc. will
cause the MIL to light up.
 Be sure to connect and lock the connectors secure ly after work. A loose (unlocked) connector will
cause the MIL to light up due to the open circuit. (Be sure the connector is free from water, grease,
dirt, bent terminals, etc.)
 Certain systems and components, especially those related to OBD, may use a new style slide-lock-
ing type harness connector. For descrip tion and how to disconnect, refer to PG-68
.
 Be sure to route and secure the harnesses properly after work. The interference of the harness with
a bracket, etc. may cause the MIL to li ght up due to the short circuit.
 Be sure to connect rubber tubes properly afte r work. A misconnected or disconnected rubber tube
may cause the MIL to light up due to the malfunction of the EVAP system or fuel injection system,
etc.
 Be sure to erase the unnecessary malfunction info rmation (repairs completed) from the ECM and
TCM (Transmission control module) before returning the vehicle to the customer.
Revision: December 20092009 QX56

PRECAUTIONSEC-481
< PRECAUTION > [VK56DE]
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PrecautionINFOID:0000000003771743

Always use a 12 volt battery as power source.
 Do not attempt to disconnect battery cables while engine is
running.
 Before connecting or disc onnecting the ECM harness con-
nector, turn ignition switch OFF and disconnect negative bat-
tery cable. Failure to do so may damage the ECM because
battery voltage is applied to ECM even if ignition switch is
turned OFF.
 Before removing parts, turn ig nition switch OFF and then dis-
connect negative battery cable.
 Do not disassemble ECM.
 If a battery cable is disconnect ed, the memory will return to
the ECM value.
The ECM will now start to sel f-control at its initial value.
Engine operation can vary slight ly when the terminal is dis-
connected. However, this is no t an indication of a malfunc-
tion. Do not replace parts b ecause of a slight variation.
 If the battery is disconnected, the following emission-related
diagnostic information will be lost within 24 hours.
- Diagnostic trouble codes
- 1st trip diagnostic trouble codes
- Freeze frame data
- 1st trip freeze frame data
- System readiness test (SRT) codes
- Test values
 When connecting ECM harness c onnector, fasten it securely
with a lever as far as it will go as shown in the figure.
 When connecting or disconnect ing pin connectors into or
from ECM, take care not to damage pin terminals (bend or
break).
Make sure that there are not any bends or breaks on ECM pin
terminal, when conn ecting pin connectors.
 Securely connect ECM harness connectors.
A poor connection can cause an extremely high (surge) volt-
age to develop in coil and cond enser, thus resulting in dam-
age to ICs.
 Keep engine control system harness at least 10 cm (4 in) away
from adjacent harness, to prevent engine control system mal-
functions due to receiving externa l noise, degraded operation
of ICs, etc.
 Keep engine control system parts and harness dry.
SEF289H
PBIB1164E
BBIA0387E
PBIB0090E
Revision: December 20092009 QX56

EC-482
< PRECAUTION >[VK56DE]
PRECAUTIONS

Before replacing ECM, perform ECM Terminals and Reference
Value inspection and make sure ECM functions properly.
Refer to EC-422, "ECM Terminal and Reference Value"
.
 Handle mass air flow sensor carefully to avoid damage.
 Do not disassemble mass air flow sensor.
 Do not clean mass air flow senso r with any type of detergent.
 Do not disassemble electric throttle control actuator.
 Even a slight leak in the ai r intake system can cause serious
incidents.
 Do not shock or jar the camshaft position sensor (PHASE),
crankshaft position sensor (POS).
 After performing each TROUBLE DIAGNOSIS, perform DTC
Confirmation Procedure or Overall Function Check.
The DTC should not be displ ayed in the DTC Confirmation
Procedure if the repair is co mpleted. The Overall Function
Check should be a good result if the repair is completed.
 When measuring ECM signals with a circuit tester, never allow
the two tester probes to contact.
Accidental contact of probes will cause a short circuit and
damage the ECM power transistor.
 Do not use ECM ground termina ls when measuring input/out-
put voltage. Doing so may result in damage to the ECM's tran-
sistor. Use a ground other than ECM terminals, such as the
ground.
 B1 indicates the bank 1, B2 indicates the bank 2 as shown in
the figure.
MEF040D
SEF217U
SEF348N
PBIB1144E
Revision: December 20092009 QX56

PRECAUTIONSEC-483
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Do not operate fuel pump when there is no fuel in lines.
 Tighten fuel hose clamps to the specified torque.
 Do not depress accelerator pedal when starting.
 Immediately after starting, do not rev up engine unnecessar-
ily.
 Do not rev up engine just prior to shutdown.
 When installing C.B. ham radio or a mobile phone, be sure to
observe the following as it may adversely affect electronic
control systems depending on installation location.
- Keep the antenna as far as possi ble from the electronic con-
trol units.
- Keep the antenna feeder line more than 20 cm (8 in) away
from the harness of electronic controls.
Do not let them run para llel for a long distance.
- Adjust the antenna and feeder line so that the standing-wave
radio can be kept smaller.
- Be sure to ground the radio to vehicle body.
BBIA0402E
SEF709Y
SEF708Y
Revision: December 20092009 QX56