2005 INFINITI QX4 air condition

COMBINATION METERS
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4. CHECK HARNESS FOR OPEN OR SHORT CIRCUIT
1. Turn the ignition switch OFF.
2. Disconnect combination meter connector M24.
3. Check continuity between fuel level sensor unit and fuel pump
harness connector C5 (A) terminal 2 (Y/L) and combination
meter harness connector M24 (B) terminal 15 (Y/L).
4. Check continuity between fuel level sensor unit and fuel pump
harness connector C5 (A) terminal 2 (Y/L) and ground.
OK or NG
OK >> GO TO 5.
NG >> Repair harness or connector.
5. CHECK FUEL LEVEL SENSOR CIRCUIT
1. Check continuity between combination meter harness connector
M24 terminal 16 (B/P) and fuel level sensor unit and fuel pump
harness connector C5 terminal 5 (B/P).
2. Check continuity between fuel level sensor unit and fuel pump
harness connector C5 terminal 5 (B/P) and ground.
OK or NG
OK >> GO TO 6.
NG >> Repair harness or connector.
6. CHECK FUEL LEVEL SENSOR UNIT
Check the fuel level sensor unit. Refer to DI-25, "
FUEL LEVEL SENSOR UNIT CHECK" .
OK or NG
OK >> GO TO 7.
NG >> Replace the fuel level sensor unit. Refer to FL-5, "
Removal and Installation" .
7. CHECK INSTALLATION CONDITION
Check fuel level sensor unit installation, and determine whether the float arm interferes or binds with any of the
internal components in the fuel tank.
OK or NG
OK >> Replace the combination meter. Refer to IP-13, "Combination Meter" .
NG >> Install the fuel level sensor unit properly.Continuity should exist.
Continuity should not exist.
WKIA4617E
Continuity should exist.
Continuity should not exist.
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DI-26
COMPASS AND THERMOMETER
Revision: October 20052005 QX56
COMPASS AND THERMOMETERPFP:24835
System DescriptionEKS00BCE
This unit displays the following items:

Earth magnetism and heading direction of vehicle.

Outside air temperature.

Caution for frozen road surfaces.
OUTSIDE TEMPERATURE DISPLAY
Push the mode switch when the ignition switch is in the ON position. The outside temperature will be displayed
in “°F”.

Selecting the indication range
Push the mode switch to change from °F → °C → OFF → °F.

The indicated temperature on the thermometer is not readily affected by engine heat. It changes only
when one of the following conditions is present.
–The temperature detected by the ambient sensor is lower than the indicated temperature on the thermom-
eter.
–The vehicle speed is greater than 20 km/h (13 MPH).
(This is to prevent the indicated temperature from being affected by engine heat during low-speed driv-
ing.)
–The ignition switch has been turned to the OFF position for more than 2 hours. (The engine is cold.)
DIRECTION DISPLAY
Push the mode switch when the ignition switch is in the ON position. The direction will be displayed.
WKIA1817E

DI-28
COMPASS AND THERMOMETER
Revision: October 20052005 QX56
Trouble DiagnosesEKS00BCG
PRELIMINARY CHECK FOR THERMOMETER
1. COOL DOWN CHECK
1. Turn the ignition switch to the ON position.
2. Cool down the ambient sensor 2 with water or ice.
Does the indicated temperature drop?
YES >> GO TO 2.
NO >> The system is malfunctioning. Refer to DI-28, "
INSPECTION/COMPASS AND THERMOMETER"
.
2. WARM UP CHECK
1. Leave the vehicle for 10 minutes.
2. With the ignition switch in the ON position, disconnect and reconnect the ambient sensor 2 connector.
Does the indicated temperature rise?
YES >> The system is OK.
NO >> The system is malfunctioning. Refer to DI-28, "
INSPECTION/COMPASS AND THERMOMETER"
.
NOTE:
The indicated temperature on the thermometer is not readily affected by engine heat. It changes only when
one of the following conditions is present.

The temperature detected by the ambient sensor is lower than the indicated temperature on the thermom-
eter.

The vehicle speed is greater than 20 km/h (13 MPH).
(This is to prevent the indicated temperature from being affected by engine heat during low-speed driv-
ing.)

The ignition switch has been turned to the OFF position for more than 2 hours. (The engine is cold.)
INSPECTION/COMPASS AND THERMOMETER
Symptom Possible causes Repair order
No display at all 1. 10A fuse
2. Ground circuit
3. Compass and thermometer1. Check 10A fuse [No. 12, located in fuse block (J/B)].
Turn the ignition switch ON and verify that battery positive volt-
age is at terminal 2 of compass and thermometer.
2. Check ground circuit for compass and thermometer.
3. Replace compass and thermometer.
Forward direction indi-
cation slips off the mark
or incorrect.1. In manual correction mode (Bar and
display vanish)
2. Zone variation change is not done1. Drive the vehicle and turn at an angle of 90°.
2. Perform the zone variation change.
Compass reading
remains unchanged.1. Vehicle speed signal is not entered
2. Compass and thermometer1. Check harness for open or short between combination meter
terminal 29 and compass and thermometer terminal 8.
2. Replace compass and thermometer.
Displays wrong tem-
perature when ambient
temperature is between
−40°C (−40°F) and
55°C (130°F). (See
NOTE above.)1. Check operation
2. Ambient sensor circuit
3. Vehicle speed signal is not entered
4. Ambient sensor 2
5. Compass and thermometer1. Perform preliminary check shown above.
2. Check harness for open or short between ambient sensor 2 and
compass and thermometer.
3. Check harness for open or short between combination meter
terminal 29 and compass and thermometer terminal 8.
4. Replace ambient sensor 2.
5. Replace compass and thermometer.
Displays SC or OC. 1. Ambient sensor circuit
2. Ambient sensor 2
3. Compass and thermometer1. Check harness for open or short between ambient sensor 2 and
compass and thermometer.
2. Replace ambient sensor 2.
3. Replace compass and thermometer.

WARNING LAMPS
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Oil Pressure Warning Lamp Stays Off (Ignition Switch ON)EKS00BCK
1. CHECK OIL PRESSURE SENSOR SIGNAL
1. Turn ignition switch ON.
2. Check voltage between combination meter harness connector
M24 terminal 20 (Y) and ground.
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
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" .
Te r m i n a l s
Condition Voltage (V) (+)
(–)
ConnectorTe r m i n a l
(Wire color)
M24 20 (Y) GroundWhen ignition switch is in ON
position. (Engine stopped)Ye s
Engine running. (Idle speed) Yes
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Continuity should exist.
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Voltage : Approx. 5V
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WARNING CHIME
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Terminals and Reference Value for Combination MeterEKS00BCT
How to Proceed With Trouble DiagnosisEKS00BCU
1. Confirm the symptom or customer complaint.
2. Understand operation description and function description. Refer to DI-42, "
System Description" .
3. Perform the preliminary check. Refer to DI-47, "
Preliminary Check" .
4. Check symptom and repair or replace the cause of malfunction.
5. Does the warning chime operate properly? If so, go to 6. If not, go to 3.
6. Inspection End.
Preliminary CheckEKS00BCV
INSPECTION FOR POWER SUPPLY AND GROUND CIRCUIT
1. CHECK FUSE AND FUSIBLE LINK
Check for blown BCM fuse or fusible link.
Refer to DI-44, "Wiring Diagram — CHIME —" .
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" .
35 O/B Combination switch output 2
ON

Light switch and wiper switch
OFF

Wiper dial position 4 36 R/W Combination switch output 1
37 B/R Key switch signal OFFKey is removed 0
Key is inserted Battery voltage
38 W/L Ignition switch ON or START ON — Battery voltage
39 L CAN-H — — —
40 P CAN-L — — —
47 SB Front door switch LH signal OFFON (open) 0
OFF (closed) 5
67 B Ground OFF — 0
70 W/B Battery power supply OFF — Battery voltage Te r m i n a l
No.Wire
colorItem Condition
Reference value (V)
(Approx.) Ignition
switchMeasurement method
SKIA5292E
Te r m i n a l
No.Wire
colorItem Condition
Reference value (V)
(Approx.) Ignition
switchMeasurement method
11 L C A N - H — — —
12 P CAN-L — — —
27 O/BSeat belt buckle pre-ten-
sioner assembly (seat belt
buckle switch) LH ONUnfastened (ON) 0
Fastened (OFF) Battery voltage
Unit Power source Fuse or fusible link No.
BCMBatteryf
Ignition switch ON or START 59

REAR SONAR SYSTEM
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Terminals And Reference Value For Sonar Control UnitEKS00BD5
How to Proceed With Trouble DiagnosisEKS00BD6
1. Confirm the symptom or customer complaint.
2. Understand operation description and function description. Refer to DI-59, "
System Description" .
3. Perform pre-diagnosis inspection. Refer to DI-64, "
Pre-diagnosis Inspection" .
4. Perform self-diagnosis. Refer to DI-64, "
Self-diagnosis Function" .
5. Perform the preliminary check. Refer to DI-66, "
Preliminary Check" .
6. Check symptom and repair or replace the cause of malfunction. Refer to DI-67, "
Symptom Chart" .
7. Does the rear sonar system operate properly? If so, go to 8. If not, go to 3.
8. Clear fault codes. Refer to DI-65, "
IDLING OR CLEARING FAULT CODES MODE" .
9. Inspection End.
TERMINAL
(COLOR)ITEMCONDITION
Reference value (V)
(Approx.) IGNITION
SWITCHOPERATION
3 (R) Sonar buzzer return ON — 0 - 12 (variable)
4 (BR/Y)Rear sonar system
OFF indicator outputONRear sonar system OFF
switch ON 0
OFF 12
5 (G/W) Reverse signal ONTransmission gear
selector leverR position 12
Transmission gear
selector leverNot R position 0
6 (B)Sonar control unit
ground —— 0
7 (L) Sonar buzzer drive
signalON — 12
8 (G/R)Sonar control unit
powerON — 12
9 (GR)Rear sonar sensor
signal - RH outerON

Rear sonar system OFF switch ON

Transmission gear selector lever in R
position

No obstacles12
10 (P)Rear sonar sensor
signal - LH outerON

Rear sonar system OFF switch ON

Transmission gear selector lever in R
position

No obstacles12
11 ( O )Rear sonar sensor
signal - LH innerON

Rear sonar system OFF switch ON

Transmission gear selector lever in R
position

Distance obstacles12
12 (LG)Rear sonar sensor
signal - RH innerON

Rear sonar system OFF switch ON

Transmission gear selector lever in R
position

Distance obstacles12
13 (LG)Rear sonar system
OFF switch signalONRear sonar system OFF
switchON 0
OFF 12
15 (Y)Rear sonar sensor
groundON — 0
16 (LG/B)Rear sonar sensor
powerON Ignition switch ON 12

REAR SONAR SYSTEM
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Symptom Chart EKS00BDA
Symptom Repair order
When the rear sonar system OFF switch is OFF, the indicator
lamp does not light and the buzzer does not sound.1. Check rear sonar system OFF switch for malfunction. Refer to
DI-68, "
REAR SONAR SYSTEM OFF SWITCH" .
2. Check rear sonar system OFF switch ground circuit.
3. Check harness and connections between rear sonar system
OFF switch and sonar control unit.
4. Replace sonar control unit. Refer to DI-68, "
SONAR CON-
TROL UNIT" .
When the rear sonar system OFF switch is OFF, the indicator
lamp does not light but buzzer sounds.1. Check rear sonar system OFF indicator for malfunction. Refer
to DI-68, "
REAR SONAR SYSTEM OFF INDICATOR" .
2. Check harness and connections between rear sonar system
OFF indicator and sonar control unit.
3. Replace sonar control unit. Refer to DI-68, "
SONAR CON-
TROL UNIT" .
When the rear sonar system OFF switch is OFF, the sonar
buzzer does not sound but indicator lamp illuminates.1. Check sonar buzzer. Refer to DI-68, "
SONAR BUZZER" .
2. Check harness and connections between sonar buzzer and
sonar control unit.
3. Replace sonar control unit. Refer to: DI-68, "
SONAR CON-
TROL UNIT" .
When rear sonar system OFF switch is ON, the rear sonar sys-
tem OFF indicator lamp lights up and the sonar buzzer sounds
intermittently (for about 4 seconds).1. Check harness between rear sonar sensors and sonar control
unit for an open condition.
2. Check rear sonar sensors for malfunction.
3. Replace sonar control unit. Refer to DI-68, "
SONAR CON-
TROL UNIT" .
The rear sonar system operates with the rear sonar system OFF
switch OFF.1. Check rear sonar system OFF switch for malfunction. Refer to
DI-68, "
REAR SONAR SYSTEM OFF SWITCH" .
2. Check rear sonar system OFF switch ground circuit.
3. Check harness and connections between rear sonar system
OFF switch and sonar control unit.
4. Replace sonar control unit. Refer to DI-68, "
SONAR CON-
TROL UNIT" .
When the transmission gear selector lever is in the R position
and the rear sonar system OFF switch is OFF, the sonar system
does not operate.1. Check for PNP switch failure. Refer to AT - 8 5 , "
SELF-DIAG-
NOSTIC RESULT MODE" .
2. Check harness and connections between sonar control unit
and PNP/reverse lamp circuits.
3. Replace sonar control unit. Refer to DI-68, "
SONAR CON-
TROL UNIT" .
When the rear sonar system OFF switch is OFF, the indicator
lamp lights up and buzzer sounds although there is no obstacle
within the detection range.1. Check for adhesion of snow, mud, or other foreign objects to
rear sonar sensors; dew condensation; etc. Refer to DI-64,
"Pre-diagnosis Inspection" .
2. Check that the rear sonar sensor is properly aligned (bumper
is not misaligned, no deformation in sensor mounting area).
3. Check harness and connections between rear sonar sensors
and sonar control unit.
4. Check rear sonar sensors for malfunction.
5. Replace sonar control unit. Refer to DI-68, "
SONAR CON-
TROL UNIT" .
The rear sonar sensors do not operate according to the distance
between each sensor and the obstacle. (There is a large error in
the obstacle detection distance).1. Check rear sonar sensors for malfunction.
2. Replace sonar control unit. Refer to DI-68, "
SONAR CON-
TROL UNIT" .
3. Check for adhesion of snow, mud, or other foreign objects to
rear sonar sensors; dew condensation; etc. Refer to DI-64,
"Pre-diagnosis Inspection" .
4. Check that the rear sonar sensor is properly aligned (bumper
is not misaligned, no deformation in sensor mounting area).

EC-1
ENGINE CONTROL SYSTEM
B ENGINE
CONTENTS
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SECTION EC
A
EC
Revision: October 20052005 QX56 INDEX FOR DTC ........................................................ 8
DTC No. Index ......................................................... 8
Alphabetical Index .................................................. 12
PRECAUTIONS ........................................................ 16
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” ................................................................ 16
On Board Diagnostic (OBD) System of Engine and
A/T .......................................................................... 16
Precaution .............................................................. 16
Wiring Diagrams and Trouble Diagnosis ................ 19
PREPARATION ......................................................... 20
Special Service Tools ............................................. 20
Commercial Service Tools ...................................... 22
ENGINE CONTROL SYSTEM .................................. 23
System Diagram ..................................................... 23
Multiport Fuel Injection (MFI) System .................... 24
Electronic Ignition (EI) System ............................... 26
Fuel Cut Control (at No Load and High Engine
Speed) .................................................................... 27
AIR CONDITIONING CUT CONTROL ..................... 28
Input/Output Signal Chart ....................................... 28
System Description ................................................ 28
AUTOMATIC SPEED CONTROL DEVICE (ASCD) ... 29
System Description ................................................ 29
Component Description .......................................... 30
CAN COMMUNICATION .......................................... 31
System Description ................................................ 31
EVAPORATIVE EMISSION SYSTEM ....................... 32
Description ............................................................. 32
Component Inspection ........................................... 35
Removal and Installation ........................................ 36
How to Detect Fuel Vapor Leakage ....................... 37
ON BOARD REFUELING VAPOR RECOVERY
(ORVR) ...................................................................... 39
System Description ................................................ 39
Diagnostic Procedure ............................................. 40
Component Inspection ........................................... 43
POSITIVE CRANKCASE VENTILATION ................. 45Description .............................................................. 45
Component Inspection ............................................ 45
IVIS (INFINITI VEHICLE IMMOBILIZER SYSTEM-
NATS) ........................................................................ 47
Description .............................................................. 47
ON BOARD DIAGNOSTIC (OBD) SYSTEM ............ 48
Introduction ............................................................. 48
Two Trip Detection Logic ........................................ 48
Emission-related Diagnostic Information ................ 49
Malfunction Indicator Lamp (MIL) ........................... 64
OBD System Operation Chart ................................ 66
BASIC SERVICE PROCEDURE ............................... 72
Basic Inspection ..................................................... 72
Idle Speed and Ignition Timing Check .................... 77
Idle Mixture Ratio Adjustment ................................. 79
VIN Registration ..................................................... 90
Accelerator Pedal Released Position Learning ...... 90
Throttle Valve Closed Position Learning ................. 90
Idle Air Volume Learning ........................................ 91
Fuel Pressure Check .............................................. 93
TROUBLE DIAGNOSIS ............................................ 95
Trouble Diagnosis Introduction ............................... 95
DTC Inspection Priority Chart ...............................101
Fail-safe Chart ......................................................103
Symptom Matrix Chart ..........................................104
Engine Control Component Parts Location ..........108
Vacuum Hose Drawing .........................................114
Circuit Diagram .....................................................115
ECM Harness Connector Terminal Layout ...........117
ECM Terminals and Reference Value ...................117
CONSULT-II Function (ENGINE) ..........................126
Generic Scan Tool (GST) Function .......................139
CONSULT-II Reference Value in Data Monitor .....141
Major Sensor Reference Graph in Data Monitor
Mode .....................................................................144
TROUBLE DIAGNOSIS - SPECIFICATION VALUE .146
Description ............................................................146
Testing Condition ..................................................146
Inspection Procedure ............................................146
Diagnostic Procedure ...........................................147