2007 INFINITI QX56 ABS

CO-14
< SERVICE INFORMATION >
RADIATOR
6. Remove the lower radiator shroud.
• Release the tabs, pull lower radiator shroud rearwards and
down to remove.
7. Remove the radiator shroud upper bolts and remove the radiator
shroud upper A.
8. Remove the A/C condenser bolts and brackets.
NOTE:
Lift A/C condenser up and forward to remove from radiator.
9. Remove A/T oil cooler bolts and oil cooler from radiator and
position aside.
WBIA0407E
WBIA0695E
WBIA0395E
WBIA0396E

COMBINATION METERSDI-5
< SERVICE INFORMATION >
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COMBINATION METERS
Component Parts and Har ness Connector LocationINFOID:0000000003533479
System DescriptionINFOID:0000000003533480
UNIFIED METER CONTROL UNIT
• Speedometer, odometer, tachometer, fuel gauge, oil pressure gauge, voltage gauge, A/T oil temperature
gauge, and water temperature gauge are controlled by the unified meter control unit, which is built into the
combination meter.
• Warning indicators are controlled by signals drawn fr om the CAN communication system, BCM (body control
module), and components connected directly to the combination meter.
• Digital meter is adopted for odometer/trip meters*, as well as the A/T position indicator display. *The record of the odometer is kept ev en if the battery cable is disconnected.
• Odometer/trip meters and A/T indicator segments can be checked in diagnosis mode.
• Meters/gauges can be checked in diagnosis mode.
Illumination control
The unified meter control unit outputs the speedometer, odometer/trip meters, tachometer, oil pressure gauge,
voltage meter, A/T indicator, A/T temperature gauge, fuel and temperature gauge lighting when the ignition
switch is turned on. When the lighting switch is turned on, the illumination control switch can be used to adjust
the brightness of the combination meter illuminati on and the odometer/trip meters and meter illumination.
When the ignition switch is turned from the OFF to the ON position, the combination meter dial lighting will
remain off for 0.7 seconds. For additional combination meter illumination control information, refer to LT-120,
"System Description".
1. IPDM E/R E122 2. Combination meter M24 3. Fuel level sensor unit and fuel pump
C5 (view with inspection hole cover
removed)
4. ECM E16 (view with battery re- moved) 5. ABS actuator and electric unit (con-
trol unit) E125 6. Oil pressure switch F4
A. Oil pan (upper)
7. A/T assembly F9
WKIA5718E

DI-6
< SERVICE INFORMATION >
COMBINATION METERS
POWER SUPPLY AND GROUND CIRCUIT
Power is supplied at all times
• through 10A fuse [No.19, located in the fuse block (J/B)]
• to combination meter terminal 8.
With the ignition switch in the ON or START position, power is supplied
• through 10A fuse [No.14, located in the fuse block (J/B)]
• to combination meter terminal 24.
Ground is supplied
• to combination meter terminal 17
• through body grounds M57, M61 and M79.
WATER TEMPERATURE GAUGE
The water temperature gauge indicates the engine coolant temperature.
ECM provides an engine coolant temperature signal to combination meter via CAN communication lines.
ENGINE OIL PRESSURE GAUGE
The engine oil pressure gauge indicates whether the engine oil pressure is low or normal.
The oil pressure gauge is controlled by the IPDM E/R (intelligent power distribution module engine room). Low
oil pressure causes oil pressure switch terminal 1 to provide ground to IPDM E/R terminal 42. The IPDM E/R
then signals the combination meter (unified meter control unit) via CAN communication lines and a low oil
pressure indication is displayed by the oil pressure gauge.
A/T OIL TEMPERATURE GAUGE
The A/T oil temperature gauge indicates the A/T fluid temperature.
TCM (transmission control module) provides an A/T flui d temperature signal to combination meter via CAN
communication lines.
VOLTAGE GAUGE
The voltage gauge indicates the battery/charging system voltage.
The voltage gauge is regulated by the unified meter control unit.
TA C H O M E T E R
The tachometer indicates engine speed in revolutions per minute (rpm).
ECM provides an engine speed signal to combination meter via CAN communication lines.
FUEL GAUGE
The fuel gauge indicates the approximate fuel level in the fuel tank.
The fuel gauge is regulated by the unified meter control unit and a variable resistor signal supplied
• to combination meter terminal 15.
• through fuel level sensor unit and fuel pump terminal 2
• through fuel level sensor unit and fuel pump terminal 5
• from combination meter terminal 16
SPEEDOMETER
ABS actuator and electric unit (contro l unit) provides a vehicle speed signal to the combination meter via CAN
communication lines.
ODO/TRIP METER
The vehicle speed signal and the memory signals from the meter memory circuit are processed by the combi-
nation meter and the mileage is displayed.
How to Change the Display
Refer to Owner's Manual for odo/tr ip meter operating instructions.
CAN COMMUNICATION SYSTEM DESCRIPTION
Refer to LAN-4.

COMBINATION METERSDI-17
< SERVICE INFORMATION >
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Refer to DI-9, "Wiring Diagram - METER -".
OK or NG
OK >> GO TO 2.
NG >> If fuse is blown, be sure to eliminate caus e of malfunction before installing new fuse. Refer to PG-
3.
2.CHECK POWER SUPPLY CIRCUIT
1. Disconnect combination meter connector.
2. Check voltage between combination meter harness connector terminals and ground.
OK or NG
OK >> GO TO 3.
NG >> Check the harness for open between combination meter and fuse.
3.CHECK GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Check continuity between combination meter harness connector terminal and ground.
OK or NG
OK >> Inspection End.
NG >> Repair harness or connector.
Vehicle Speed Signal InspectionINFOID:0000000003533491
1.CHECK ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT) SELF-DIAGNOSIS
Refer to BRC-26, "
CONSULT-II Function (ABS)".
OK or NG
OK >> Replace the combination meter. Refer to IP-10, "Removal and Installation".
NG >> Perform "Diagnostic Procedure" for displayed DTC. Refer to BRC-26, "
CONSULT-II Function
(ABS)".
Engine Oil Pressure Signal InspectionINFOID:0000000003533492
1.CHECK SELF-DIAGNOSTIC RESULTS OF IPDM E/R
Select "IPDM E/R" on CONSULT-II, and perform self-diagnosis of IPDM E/R. Refer to PG-18, "
CONSULT-II
Function (IPDM E/R)".
Unit Power source Fuse No.
Combination meter Battery 19
Ignition switch ON or START 14
Terminals Ignition switch position
(+) (–) OFF ACC ON
Connector Terminal
M24 8
Ground Battery
voltage Battery
voltage Battery
voltage
24 0V 0V Battery
voltage
WKIA5606E
Te r m i n a l s
Continuity
(+)
(–)
Connector Terminal
M24 17 Ground Yes
WKIA1526E

ENGINE CONTROL SYSTEM
EC-25
< SERVICE INFORMATION >
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*1: This sensor is not used to control the engine system. This is used only for the on board diagnosis.
*2: This signal is sent to the ECM through CAN communication line.
*3: ECM determines the start signal status by the signals of engine speed and battery voltage.
SYSTEM DESCRIPTION
The amount of fuel injected from the fuel injector is determined by the ECM. The ECM controls the length of
time the valve remains open (injection pulse duration). The amount of fuel injected is a program value in the
ECM memory. The program value is preset by engine operating conditions. These conditions are determined
by input signals (for engine speed and intake air) from both the crankshaft position sensor and the mass air
flow sensor.
VARIOUS FUEL INJECTION INCREASE/DECREASE COMPENSATION
In addition, the amount of fuel injected is compensated to improve engine performance under various operat-
ing conditions as listed below.
• During warm-up
• When starting the engine
• During acceleration
• Hot-engine operation
• When selector lever is changed from N to D
• High-load, high-speed operation

• During deceleration
• During high engine speed operation
MIXTURE RATIO FEEDBACK CONTROL (CLOSED LOOP CONTROL)
Sensor Input signal to ECM ECM function Actuator
Crankshaft position sensor (POS)
Engine speed*
3
Piston position
Fuel injection
& mixture ratio
controlFuel injector Camshaft position sensor (PHASE)
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Air fuel ratio (A/F) sensor 1 Density of oxygen in exhaust gas
Throttle position sensor Throttle position
Accelerator pedal position sensor Accelerator pedal position
Park/neutral position (PNP) switch Gear position
Knock sensor Engine knocking condition
Battery
Battery voltage*
3
Power steering pressure sensor Power steering operation
Heated oxygen sensor 2*
1Density of oxygen in exhaust gas
ABS actuator and electric unit (control unit)
VDC/TCS operation command*
2
Air conditioner switch
Air conditioner operation*2
Wheel sensor
Vehicle speed*2
PBIB3020E

EC-40
< SERVICE INFORMATION >
ON BOARD REFUELING VAPOR RECOVERY (ORVR)
ON BOARD REFUELING VAPOR RECOVERY (ORVR)
System DescriptionINFOID:0000000003531598
From the beginning of refueling, the air and vapor inside the fuel tank go through refueling EVAP vapor cut
valve and EVAP/ORVR line to the EVAP canister. The vapor is absorbed by the EVAP canister and the air is
released to the atmosphere.
When the refueling has reached the full level of the fuel tank, the refueling EVAP vapor cut valve is closed and
refueling is stopped because of auto shut-off. The vapor which was absorbed by the EVAP canister is purged
during driving.
WARNING:
When conducting inspections below, be sure to observe the following:
• Put a “CAUTION: FLAMMABLE” sign in workshop.
• Do not smoke while servicing fuel system. Keep open flames and sparks away from work area.
• Be sure to furnish the workshop with a CO
2 fire extinguisher.
CAUTION:
• Before removing fuel line parts, carry out the following procedures:
- Put drained fuel in an explosion-proof container and put lid on securely.
- Release fuel pressure from fuel line. Refer to EC-80, "
Fuel Pressure Check" .
- Disconnect battery ground cable.
• Always replace O-ring when the fuel gauge retainer is removed.
• Do not kink or twist hose and tube when they are installed.
• Do not tighten hose and clamps excessively to avoid damaging hoses.
• After installation, run engine and check for fuel leaks at connection.
• Do not attempt to top off the fuel tank after the fuel pump nozzle shuts off automatically.
Continued refueling may cause fuel overflow, resulting in fuel spray and possibly a fire.
Diagnosis ProcedureINFOID:0000000003531599
SYMPTOM: FUEL ODOR FROM EVAP CANISTER IS STRONG.
1.CHECK EVAP CANISTER
1. Remove EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor
attached.
2. Weigh the EVAP canister with EVAP canister vent control valve and EVAP control system pressure sensor
attached.
The weight should be less than 2.5 kg (5.5 lb).
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
2.CHECK IF EVAP CANISTER SATURATED WITH WATER
PBIB1068E

EC-54
< SERVICE INFORMATION >
ON BOARD DIAGNOSTIC (OBD) SYSTEM
A sample of CONSULT-II display for DTC and 1st trip DTC is shown below. DTC or 1st trip DTC of a malfunc-
tion is displayed in SELF-DIAGNOSTIC RESULTS mode of CONSULT-II. Time data indicates how many times
the vehicle was driven after the last detection of a DTC.
If the DTC is being detected currently, the time data will be [0].
If a 1st trip DTC is stored in the ECM, the time data will be [1t].
FREEZE FRAME DATA AND 1ST TRIP FREEZE FRAME DATA
The ECM records the driving conditions such as fuel system status, calculated load value, engine coolant tem-
perature, short term fuel trim, long term fuel trim, engine speed, vehicle speed, absolute throttle position, base
fuel schedule and intake air temperature at the moment a malfunction is detected.
Data which are stored in the ECM memory, along with the 1st trip DTC, are called 1st trip freeze frame data.
The data, stored together with the DTC data, are called freeze frame data and displayed on CONSULT-II or
GST. The 1st trip freeze frame data can only be displayed on the CONSULT-II screen, not on the GST. For
details, see E C - 111 , "
CONSULT-II Function (ENGINE)".
Only one set of freeze frame data (either 1st trip freeze frame data or freeze frame data) can be stored in the
ECM. 1st trip freeze frame data is stored in the ECM memory along with the 1st trip DTC. There is no priority
for 1st trip freeze frame data and it is updated each time a different 1st trip DTC is detected. However, once
freeze frame data (2nd trip detection/MIL on) is stored in the ECM memory, 1st trip freeze frame data is no
longer stored. Remember, only one set of freeze frame data can be stored in the ECM. The ECM has the fol-
lowing priorities to update the data.
For example, the EGR malfunction (Priority: 2) was detected and the freeze frame data was stored in the 2nd
trip. After that when the misfire (Priority: 1) is detected in another trip, the freeze frame data will be updated
from the EGR malfunction to the misfire. The 1st trip freeze frame data is updated each time a different mal-
function is detected. There is no priority for 1st trip freeze frame data. However, once freeze frame data is
stored in the ECM memory, 1st trip freeze data is no longer stored (because only one freeze frame data or 1st
trip freeze frame data can be stored in the ECM). If freeze frame data is stored in the ECM memory and freeze
frame data with the same priority occurs later, the first (original) freeze frame data remains unchanged in the
ECM memory.
Both 1st trip freeze frame data and freeze frame data (along with the DTCs) are cleared when the ECM mem-
ory is erased. Procedures for clearing the ECM memory are described in "HOW TO ERASE EMISSION-
RELATED DIAGNOSTIC INFORMATION".
SYSTEM READINESS TEST (SRT) CODE
System Readiness Test (SRT) code is specified in Service $01 of SAE J1979.
As part of an enhanced emissions test for Inspection & Maintenance (I/M), certain states require the status of
SRT be used to indicate whether the ECM has completed self-diagnosis of major emission systems and com-
ponents. Completion must be verified in order for the emissions inspection to proceed.
If a vehicle is rejected for a State emissions inspection due to one or more SRT items indicating “INCMP”, use
the information in this Service Manual to set the SRT to “CMPLT”.
In most cases the ECM will automatically complete its self-diagnosis cycle during normal usage, and the SRT
status will indicate “CMPLT” for each application system. Once set as “CMPLT”, the SRT status remains
“CMPLT” until the self-diagnosis memory is erased.
Occasionally, certain portions of the self-diagnostic test may not be completed as a result of the customer's
normal driving pattern; the SRT will indicate “INCMP” for these items.
PBIB0911E
Priority Items
1Freeze frame data Misfire — DTC: P0300 - P0308
Fuel Injection System Function — DTC: P0171, P0172, P0174, P0175
2 Except the above items (Includes A/T related items)
3 1st trip freeze frame data

TROUBLE DIAGNOSIS
EC-91
< SERVICE INFORMATION >
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1 - 6: The numbers refer to the order of inspection.
(continued on next page)
SYSTEM — ENGINE MECHANICAL & OTHER
Camshaft position sensor (PHASE) circuit 3 2EC-342
Vehicle speed signal circuit 2 3 3 3EC-429
Power steering pressure sensor circuit 2 3 3EC-435
ECM 22333333333EC-440,
EC-444
Intake valve timing control solenoid valve cir-
cuit32 13223 3EC-178
Park/Neutral position (PNP) switch circuit 3 3 3 3 3EC-452
Refrigerant pressure sensor circuit 2 3 3 4EC-638
Electrical load signal circuit 3EC-606
Air conditioner circuit 223333333 3 2AT C - 3 0
ABS actuator and electric unit (control unit) 4EC-467
,
EC-468

or BRC-11
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