2004 INFINITI QX56 Air

CO-18Revision: August 2007
THERMOSTAT AND WATER PIPING
2004 QX56
CAUTION:
Perform when the engine is cold.
2. Remove air duct and resonator assembly. Refer to EM-14, "
REMOVAL" .
3. Remove engine room cover using power tools.
4. Disconnect heater hose (heater core side).
5. Remove heater hose bracket.
6. Disconnect the water cut valve connector.
7. Remove the water cut valve
INSPECTION AFTER REMOVAL

Place a thread so that it is caught in the valve of the thermostat.
Immerse fully in a container filled with water. Heat while stirring.

The valve opening temperature is the temperature at which the
valve opens and falls from the thread.

Continue heating. Check the full-open lift amount.

After checking the full-open lift amount, lower the water temper-
ature and check the valve closing temperature.
Standard values:
INSTALLATION
Installation is in the reverse order of removal.
Installation of Thermostat

Install the thermostat with the whole circumference of each
flange part fit securely inside the rubber ring as shown.

Install the thermostat with the jiggle valve facing upwards.
Installation of Water Outlet Pipe and Heater Pipe
First apply a neutral detergent to the O-rings, then quickly insert the insertion parts of the water outlet pipe and
heater pipe into the installation holes.
INSPECTION AFTER INSTALLATION

Check for leaks of the engine coolant. Refer to CO-8, "CHECKING COOLING SYSTEM FOR LEAKS" .

Start and warm up the engine. Visually make sure that there is no leaks of the engine coolant.
SL C2 52 B
Thermostat
Valve opening temperature 80 - 84°C (176 - 183° F)
Full-open lift amount More than 10 mm/ 95°C (0.39 in/ 203°F)
Valve closing temperature 77°C (171°F) or higher
KBIA2502E

DI-1
DRIVER INFORMATION SYSTEM
K ELECTRICAL
CONTENTS
C
D
E
F
G
H
I
J
L
M
SECTION DI
A
B
DI
Revision: August 20072004 QX56 PRECAUTION ............................................................ 3
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” .................................................................. 3
Wiring Diagrams and Trouble Diagnosis .................. 3
PREPARATION ........................................................... 4
Commercial Service Tool ......................................... 4
COMBINATION METERS ........................................... 5
System Description .................................................. 5
UNIFIED METER CONTROL UNIT ...................... 5
POWER SUPPLY AND GROUND CIRCUIT ........ 6
WATER TEMPERATURE GAUGE ........................ 6
ENGINE OIL PRESSURE GAUGE ....................... 6
A/T OIL TEMPERATURE GAUGE ........................ 6
VOLTAGE GAUGE ................................................ 6
TACHOMETER ..................................................... 6
FUEL GAUGE ....................................................... 6
SPEEDOMETER ................................................... 6
CAN COMMUNICATION SYSTEM DESCRIP-
TION ...................................................................... 6
Component Parts and Harness Connector Location ..... 7
Combination Meter ................................................... 8
CHECK .................................................................. 8
Circuit Diagram ........................................................ 9
Wiring Diagram — METER — ................................ 10
Terminals and Reference Value for Combination
Meter ...................................................................... 12
Meter/Gauge Operation and Odo/Trip Meter ......... 13
SELF-DIAGNOSIS FUNCTION .......................... 13
HOW TO INITIATE COMBINATION METER
SELF- DIAGNOSIS MODE ................................. 13
COMBINATION METER SELF-DIAGNOSIS
MODE FUNCTIONS ........................................... 13
How to Proceed With Trouble Diagnosis ................ 17
Diagnosis Flow ....................................................... 17
Power Supply and Ground Circuit Inspection ........ 18
Symptom Chart ...................................................... 19
Vehicle Speed Signal Inspection ............................ 19
Engine Oil Pressure Signal Inspection ................... 19
Water Temperature Signal Inspection .................... 21Engine Speed Signal Inspection ............................. 21
Fuel Level Sensor Unit Inspection .......................... 22
FUEL LEVEL SENSOR UNIT ............................. 22
LOW-FUEL WARNING LAMP ............................. 22
Fuel Gauge Fluctuates, Indicates Wrong Value, or
Varies ...................................................................... 24
Fuel Gauge Does Not Move to Full-position ........... 24
Electrical Components Inspection .......................... 25
FUEL LEVEL SENSOR UNIT CHECK ................ 25
Removal and Installation of Combination Meter ..... 25
COMPASS AND THERMOMETER ........................... 26
System Description ................................................. 26
OUTSIDE TEMPERATURE DISPLAY ................. 26
DIRECTION DISPLAY ......................................... 26
Wiring Diagram — COMPAS — ............................. 27
Trouble Diagnoses ................................................. 28
PRELIMINARY CHECK FOR THERMOMETER ... 28
INSPECTION/COMPASS AND THERMOME-
TER ..................................................................... 28
Calibration Procedure for Compass ....................... 29
CORRECTION FUNCTIONS OF COMPASS ...... 29
INITIAL CORRECTION PROCEDURE FOR
COMPASS ........................................................... 30
WARNING LAMPS .................................................... 31
Schematic ............................................................... 31
Wiring Diagram — WARN — .................................. 32
Oil Pressure Warning Lamp Stays Off (Ignition
Switch ON) ............................................................. 38
Oil Pressure Warning Lamp Does Not Turn Off (Oil
Pressure Is Normal) ................................................ 40
A/T INDICATOR ........................................................ 41
Wiring Diagram — AT/IND — ................................. 41
A/T Indicator Does Not Illuminate ........................... 42
WARNING CHIME ..................................................... 43
Component Parts and Harness Connector Location ... 43
System Description ................................................. 44
FUNCTION .......................................................... 44
IGNITION KEY WARNING CHIME ..................... 44
LIGHT WARNING CHIME ................................... 44
SEAT BELT WARNING CHIME ........................... 44

PRECAUTION
DI-3
C
D
E
F
G
H
I
J
L
MA
B
DI
Revision: August 20072004 QX56
PRECAUTION PFP:00011
Precautions for Supplemental Restraint System (SRS) “AIR BAG” and “SEAT
BELT PRE-TENSIONER”
EKS007DI
The Supplemental Restraint System such as “AIR 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 whether 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.
WA RN ING:

To avoid rendering the SRS inoperative, 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 per-
formed by an authorized NISSAN/INFINITI dealer.

Improper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the SRS section.

Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or
harness connectors.
Wiring Diagrams and Trouble Diagnosis EKS007DJ
When you read wiring diagrams, refer to the following:

Refer to GI-15, "How to Read Wiring Diagrams" .

Refer to PG-4, "POWER SUPPLY ROUTING CIRCUIT" for power distribution circuit.
When you perform trouble diagnosis, refer to the following:

Refer to GI-11, "HOW TO FOLLOW TEST GROUPS IN TROUBLE DIAGNOSES" .

Refer to GI-27, "How to Perform Efficient Diagnosis for an Electrical Incident" .

COMBINATION METERS
DI-17
C
D
E
F
G
H
I
J
L
MA
B
DI
Revision: August 20072004 QX56
How to Proceed With Trouble DiagnosisEKS007DS
1. Confirm the symptom or customer complaint.
2. Perform diagnosis according to diagnosis flow. Refer to DI-17, "
Diagnosis Flow" .
3. According to the symptom chart, repair or replace the cause of the symptom.
4. Does the meter operate normally? If so, go to 5. If not, go to 2.
5. Inspection End.
Diagnosis FlowEKS007DT
1. CHECK WARNING INDICATOR ILLUMINATION
1. Turn ignition switch ON.
2. Make sure warning indicators (such as malfunction indicator lamp and oil pressure low/coolant tempera-
ture high warning indicator) illuminate.
Do warning indicators illuminate?
YES >> GO TO 2.
NO >> Check ignition power supply system of combination meter. Refer to DI-18, "
Power Supply and
Ground Circuit Inspection" .
2. CHECK SELF-DIAGNOSIS OPERATION OF COMBINATION METER
Perform combination meter self-diagnosis. Refer to DI-13, "
SELF-DIAGNOSIS FUNCTION" .
Does self-diagnosis function operate?
YES >> GO TO 3.
NO >> Check the following.

Combination meter power supply and ground circuit. Refer to DI-18, "Power Supply and
Ground Circuit Inspection" .
3. CHECK ODOMETER OPERATION
Check segment display status of odometer.
Is the display normal?
YES >> GO TO 4.
NO >> Replace the combination meter. Refer to IP-13, "
Combi-
nation Meter" .
4. CHECK COMBINATION METER CIRCUIT
Check indication of each meter/gauge in self-diagnosis mode.
OK or NG
OK >> Go to DI-19, "Symptom Chart" .
NG >> Replace the combination meter. Refer to IP-13, "
Combi-
nation Meter" .
WKIA1531E
WKIA1814E

DI-18
COMBINATION METERS
Revision: August 20072004 QX56
Power Supply and Ground Circuit InspectionEKS007DU
1. CHECK FUSES
Check for blown combination meter fuses.
Refer to DI-10, "Wiring Diagram — METER —" .
OK or NG
OK >> GO TO 2.
NG >> If fuse is blown, be sure to eliminate cause of malfunction before installing new fuse. Refer to PG-
4, "POWER SUPPLY ROUTING CIRCUIT" .
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
Check continuity between combination meter harness connector ter-
minals and ground.
OK or NG
OK >> Inspection End.
NG >> Repair harness or connector.
Unit Power source Fuse No.
Combination meter Battery 19
Ignition switch ON or START 14
Ignition switch ACC or ON 4
Terminals Ignition switch position
(+)
(–) OFF ACC ON
ConnectorTe r m i n a l
(Wire color)
M241 (O)
Ground0VBattery
voltageBattery
voltage
8 (Y/R)Battery
voltageBattery
voltageBattery
voltage
24 (O/L) 0V 0VBattery
voltage
WKIA1815E
Te r m i n a l s
Continuity (+)
(–)
ConnectorTe r m i n a l
(Wire color)
M24 17 (B) Ground Yes
WKIA1526E

DI-20
COMBINATION METERS
Revision: August 20072004 QX56
2. CHECK OIL PRESSURE SENSOR GROUND CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect combination meter connector M24 and oil pressure
sensor connector F4.
3. Check continuity between combination meter harness connector
M24 terminal 16 (B/P) and oil pressure sensor harness connec-
tor F4 terminal 3 (B/P).
OK or NG
OK >> Replace the combination meter. Refer to IP-13, "Combi-
nation Meter" .
NG >> Repair harness or connector.
3. CHECK OIL PRESSURE SENSOR REFERENCE VOLTAGE
1. Turn ignition switch OFF.
2. Disconnect oil pressure sensor connector F4.
3. Turn ignition switch ON.
4. Check voltage between combination meter harness connector
M24 terminal 22 (GR/L) and ground.
OK or NG
OK >> GO TO 4.
NG >> Replace the combination meter. Refer to IP-13, "
Combi-
nation Meter" .
4. CHECK OIL PRESSURE SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect combination meter connector M24.
3. Check continuity between combination meter harness connector M24 terminal 22 (GR/L) and oil pressure
sensor harness connector F4 terminal 1 (GR/L).
4. Check continuity between combination meter harness connector
M24 terminal 22 (GR/L) and ground.
OK or NG
OK >> GO TO 5.
NG >> Repair harness or connector.Continuity should exist.
WKIA1837E
Voltage : Approx. 5V
WKIA1834E
Continuity should exist.
Continuity should not exist.
WKIA1835E

COMBINATION METERS
DI-21
C
D
E
F
G
H
I
J
L
MA
B
DI
Revision: August 20072004 QX56
5. CHECK OIL PRESSURE SENSOR SIGNAL CIRCUIT
1. Check continuity between combination meter harness connector M24 terminal 20 (Y) and oil pressure
sensor harness connector F4 terminal 2 (Y).
2. Check continuity between combination meter harness connector
M24 terminal 20 (Y) and ground.
OK or NG
OK >> GO TO 6.
NG >> Repair harness or connector.
6. CHECK OIL PRESSURE SENSOR GROUND CIRCUIT
Check continuity between combination meter harness connector
M24 terminal 16 (B/P) and ground.
OK or NG
OK >> Replace oil pressure sensor.
NG >> Repair harness or connector.
Water Temperature Signal Inspection EKS007DX
1. CHECK ECM SELF-DIAGNOSIS
Perform ECM self-diagnosis. Refer to EC-107, "
SELF-DIAG RESULTS MODE" .
OK or NG
OK >> Replace the combination meter. Refer to IP-13, "Combination Meter" .
NG >> Perform "Diagnostic procedure" for displayed DTC. Refer to EC-71, "
TROUBLE DIAGNOSIS" .
Engine Speed Signal Inspection EKS007DY
1. CHECK ECM SELF-DIAGNOSIS
Perform ECM self-diagnosis. Refer to EC-107, "
SELF-DIAG RESULTS MODE" .
OK or NG
OK >> Replace the combination meter. Refer to IP-13, "Combination Meter" .
NG >> Perform "Diagnostic procedure" for displayed DTC. Refer to EC-71, "
TROUBLE DIAGNOSIS" . Continuity should exist.
Continuity should not exist.
WKIA1836E
Continuity should not exist.
WKIA2685E

DI-22
COMBINATION METERS
Revision: August 20072004 QX56
Fuel Level Sensor Unit InspectionEKS007DZ
FUEL LEVEL SENSOR UNIT
The following symptoms do not indicate a malfunction.

Depending on vehicle position or driving circumstance, the fuel in the tank shifts and the indication may
fluctuate.

If the vehicle is fueled with the ignition switch ON, the indication will update slowly.

If the vehicle is tilted when the ignition switch is turned ON, fuel in the tank may flow to one direction
resulting in a change of reading.
LOW-FUEL WARNING LAMP
Depending on vehicle posture or driving circumstances, the fuel level in the tank varies, and the warning lamp
ON timing may be changed.
1. CHECK SELF-DIAGNOSIS
Perform the combination meter self-diagnosis. Refer to DI-13, "
SELF-DIAGNOSIS FUNCTION" .
OK or NG
OK >> GO TO 2.
NG >> Replace the combination meter. Refer to IP-13, "
Combination Meter" .
2. CHECK HARNESS CONNECTOR
1. Turn the ignition switch OFF.
2. Check combination meter and fuel level sensor unit and fuel pump terminals (meter-side, and harness-
side) for poor connection.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace terminals or connectors.
3. CHECK HARNESS CONNECTOR OUTPUT SIGNAL
1. Disconnect fuel level sensor unit and fuel pump connector.
2. Turn ignition switch ON.
3. Check voltage between combination meter harness connector
M24 terminal 15 (Y/L) and ground.
OK or NG
OK >> GO TO 4.
NG >> Replace the combination meter. Refer to IP-13, "
Combi-
nation Meter" . Battery voltageWKIA1816E