2010 INFINITI QX56 ecm

EC-476
< 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-459, "
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 example. 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: April 20092010 QX56

EC-478
< 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-104,
EC-110
Engine coolant temperature sensor circuit
333
EC-121,
EC-129
Air fuel ratio (A/F ) sensor 1 circuit EC-137
,
EC-141
,
EC-145
,
EC-149
,
EC-382

Throttle position sensor circuit 22EC-125
,
EC-188
,
EC-306
,
EC-308
,
EC-374
Accelerator pedal position sensor circuit 3 2 1EC-284
,
EC-367
,
EC-370
,
EC-378
Knock sensor circuit 23EC-198
Crankshaft position sensor (POS) circuit 2 2 EC-201
Camshaft position sensor (PHASE) circuit 3 2 EC-205
Vehicle speed signal circuit2 3 33EC-275
Power steering pressu re sensor circuit 23 3 EC-281
ECM 22333333333 EC-284,
EC-286
Intake valve timing control solenoid valve cir-
cuit 32 13223 3
EC-101
Park/Neutral position (PNP) signal circuit3 3 3 33EC-292
Refrigerant pressure sensor circuit 233 4 EC-419
Electrical load signal circuit 3EC-394
Air conditioner circuit 223333333 3 2 HAC-25
ABS actuator and electric unit (control unit) 4 BRC-36
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: April 20092010 QX56

NORMAL OPERATING CONDITIONEC-481
< SYMPTOM DIAGNOSIS > [VK56DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
NORMAL OPERATING CONDITION
Fuel Cut Control (at No
Load and High Engine Speed)INFOID:0000000005149501
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 ECMECM functionActuator
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: April 20092010 QX56

EC-482
< PRECAUTION >[VK56DE]
PRECAUTIONS
PRECAUTION
PRECAUTIONS
Precaution for Supplemental Restraint Syst
em (SRS) "AIR BAG" and "SEAT BELT
PRE-TENSIONER"
INFOID:0000000005149502
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 severity 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 SRS 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 NISSAN/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 SRS section.
• Do not use electrical test equipmen t on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harn esses can be identified by yellow and/or orange harnesses or har-
ness connectors.
On Board Diagnosis (OBD) S ystem of Engine and A/TINFOID:0000000005149503
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 switch 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-64
.
• 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.
PrecautionINFOID:0000000005149504
•Always use a 12 volt battery as power source.
• Do not attempt to disconnect battery cables while engine is
running.
• Before connecting or disconnecting 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.
SEF289H
Revision: April 20092010 QX56

PRECAUTIONSEC-483
< PRECAUTION > [VK56DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
•
Do not disassemble ECM.
• If a battery cable is disconnected, 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 not an indication of a malfunc-
tion. Do not replace parts because 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 disconnecting 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 connecting 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.
• Before replacing ECM, perform ECM Terminals and Reference
Value inspection and make sure ECM functions properly.
Refer to EC-425, "
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 th rottle control actuator.
• Even a slight leak in the air intake system can cause serious
incidents.
• Do not shock or jar the camsh aft position sensor (PHASE),
crankshaft position sensor (POS).
PBIB1164E
BBIA0387E
PBIB0090E
MEF040D
Revision: April 20092010 QX56

EC-484
< PRECAUTION >[VK56DE]
PRECAUTIONS
•
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 terminals 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.
SEF217U
SEF348N
PBIB1144E
Revision: April 20092010 QX56

ENGINE ASSEMBLYEM-79
< REMOVAL AND INSTALLATION >
C
DE
F
G H
I
J
K L
M A
EM
NP
O
1. Release the fuel pressure. Refer to
EC-489, "Fuel Pressure Check".
2. Drain the engine coolant. Refer to CO-11, "
Changing Engine Coolant".
3. Drain the engine oil. Refer to LU-9, "
Changing Engine Oil".
4. Partially drain the A/T fluid. Refer to TM-150, "
Changing the A/T Fluid (ATF)".
5. Disconnect the battery negative and positive terminal. Refer to PG-74, "
Removal and Installation".
6. Remove the engine hood. Refer to DLK-234, "
Removal and Installation of Hood Assembly".
7. Remove the cowl extension. Refer to EXT-18, "
Removal and Installation".
8. Remove the engine room cover using power tools.
9. Remove the air duct and air cleaner case assembly. Refer to EM-25, "
Removal and Installation".
10. Disconnect the vacuum hose between the vehicle and engine and set it aside.
11. Remove the radiator assembly and hoses. Refer to CO-15, "
Removal and Installation".
12. Remove the drive belt. Refer to EM-13, "
Removal and Installation".
13. Remove the fan blade. Refer to CO-18, "
Removal and Installation (Crankshaft Driven Type)".
14. Disconnect the engine room harness from the fuse box and set it aside.
15. Disconnect the ECM.
16. Disconnect the engine room harness from the engine side and set it aside.
17. Disconnect the engine harness grounds.
18. Disconnect the power steering reservoir t ank from the engine and move it aside.
19. Disconnect the power steering oil pump from the engine. Move it aside and secure it using suitable wire or rope. Refer to ST-26, "
Removal and Installation"
20. Remove the A/C compressor bolts and set the compressor aside. Refer to HA-31, "Removal and Installa-
tion for Compressor" (ATC).
21. Disconnect the brake booster vacuum line.
22. Disconnect the EVAP line.
23. Disconnect the fuel hose at the engine side connection. Refer to EM-40, "
Removal and Installation".
24. Disconnect the heater hoses at the cowl, and in stall plugs to avoid leakage of engine coolant.
25. Remove the A/T oil level indicator and indicator tube upper bolts.
26. Remove the front final drive assembly (4WD only). Refer to DLN-215, "
Removal and Installation".
27. Remove the exhaust manifolds. Refer to EM-30, "
Removal and Installation".
28. Install the engine slingers into the left bank cylinder head and right bank cylinder head.
29. Disconnect and remove the crankshaft position sensor (POS). Refer to EM-82, "
Exploded View".
30. Remove the A/T. Refer to TM-186, "
Removal and Installation
(2WD)" or TM-188, "Removal and Installation (4WD)".
31. Lift using a hoist and secure the engine in position.
32. Remove the engine assembly from the vehicle, avoid interfer- ence with the vehicle body.
CAUTION:
WBIA0795E
Engine slinger torque: 45.0 N·m (4.6 kg-m, 33 ft-lb)
WBIA0715E
Revision: April 20092010 QX56

DIAGNOSIS SYSTEM (IPDM E/R)EXL-23
< FUNCTION DIAGNOSIS >
C
DE
F
G H
I
J
K
M A
B
EXL
N
O P
Concept of auto active test
• IPDM E/R starts the auto active test with the door
switch signals transmitted by BCM via CAN communica-
tion. Therefore, the CAN communication line between IPDM E/R and BCM is considered normal if the auto
active test starts successfully.
• The auto active test facilitates troubleshooting if any systems controlled by IPDM E/R cannot be operated.
Diagnosis chart in auto active test mode
3 Tail, license and parking lamps 10 seconds
4 Front fog lamps 10 seconds
5 Headlamps LO for 10 seconds → HI on-off for 5 seconds
6 A/C compressor (magnet clutch) ON ⇔ OFF 5 times
7 Cooling fan 10 seconds
Operation
sequence Inspection Location
Operation
WKIA5163E
SymptomInspection contentsPossible cause
Oil pressure low warning indicator does not operate Perform auto active test.
Does the oil pressure low
warning indicator operate?YES
• IPDM E/R signal input cir-
cuit
• ECM signal input circuit
• CAN communication signal
between ECM and combi-
nation meter
NO • CAN communication signal
between IPDM E/R, BCM
and combination meter
Oil pressure gauge does not operate Perform auto active test.
Does the oil pressure gauge
operate?YES IPDM E/R signal input circuit
NO • CAN communication signal
between IPDM E/R, BCM
and combination meter
Rear window defogger does not operate Perform auto active test.
Does the rear window defog-
ger operate?YES BCM signal input circuit
NO • Harness or connector be-
tween A/C and AV switch
assembly and AV control
unit
• CAN communication signal between BCM and IPDM E/
R
Revision: April 20092010 QX56