2005 INFINITI QX4 heating

OVERHEATING CAUSE ANALYSIS
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Revision: October 20052005 QX56
Except cool-
ing system
parts mal-
function— Overload on engineAbusive drivingHigh engine rpm under no
load
Driving in low gear for
extended time
Driving at extremely high
speed
Powertrain system mal-
function
— Installed improper size
wheels and tires
Dragging brakes
Improper ignition timing
Blocked or restricted air
flowBlocked bumper —
— Blocked radiator grilleInstalled car brassiere
Mud contamination or
paper clogging
Blocked radiator —
Blocked condenser
Blocked air flow
Installed large fog lamp Symptom Check items

CO-20Revision: October 2005
THERMOSTAT AND WATER PIPING
2005 QX56
CAUTION:
Perform when the engine is cold.
2. Remove the air duct and resonator assembly. Refer to EM-14, "
REMOVAL" .
3. Remove the engine room cover using power tool.
4. Disconnect the heater hose (heater core side).
5. Remove the 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-10, "CHECKING COOLING SYSTEM FOR LEAKS" .

Start and warm up the engine. Visually check for 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

EC-5
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ECA
Revision: October 20052005 QX56 Component Inspection ......................................... 413
Removal and Installation ...................................... 414
DTC P1146, P1166 HO2S2 ..................................... 415
Component Description ........................................ 415
CONSULT-II Reference Value in Data Monitor Mode
. 415
On Board Diagnosis Logic ................................... 415
DTC Confirmation Procedure ............................... 416
Overall Function Check ........................................ 416
Wiring Diagram .................................................... 418
Diagnostic Procedure ........................................... 421
Component Inspection ......................................... 424
Removal and Installation ...................................... 425
DTC P1147, P1167 HO2S2 ..................................... 426
Component Description ........................................ 426
CONSULT-II Reference Value in Data Monitor Mode
. 426
On Board Diagnosis Logic ................................... 426
DTC Confirmation Procedure ............................... 427
Overall Function Check ........................................ 427
Wiring Diagram .................................................... 429
Diagnostic Procedure ........................................... 432
Component Inspection ......................................... 435
Removal and Installation ...................................... 436
DTC P1148, P1168 CLOSED LOOP CONTROL .... 437
On Board Diagnosis Logic ................................... 437
DTC P1211 TCS CONTROL UNIT ......................... 438
Description ........................................................... 438
On Board Diagnosis Logic ................................... 438
DTC Confirmation Procedure ............................... 438
Diagnostic Procedure ........................................... 438
DTC P1212 TCS COMMUNICATION LINE ............ 439
Description ........................................................... 439
On Board Diagnosis Logic ................................... 439
DTC Confirmation Procedure ............................... 439
Diagnostic Procedure ........................................... 439
DTC P1217 ENGINE OVER TEMPERATURE ....... 440
Description ........................................................... 440
CONSULT-II Reference Value in Data Monitor Mode
. 440
On Board Diagnosis Logic ................................... 441
Overall Function Check ........................................ 441
Wiring Diagram .................................................... 443
Diagnostic Procedure ........................................... 445
Main 12 Causes of Overheating ........................... 448
Component Inspection ......................................... 449
DTC P1225 TP SENSOR ........................................ 450
Component Description ........................................ 450
On Board Diagnosis Logic ................................... 450
DTC Confirmation Procedure ............................... 450
Diagnostic Procedure ........................................... 451
Removal and Installation ...................................... 451
DTC P1226 TP SENSOR ........................................ 452
Component Description ........................................ 452
On Board Diagnosis Logic ................................... 452
DTC Confirmation Procedure ............................... 452
Diagnostic Procedure ........................................... 453
Removal and Installation ...................................... 453
DTC P1229 SENSOR POWER SUPPLY ................ 454On Board Diagnosis Logic ....................................454
DTC Confirmation Procedure ...............................454
Wiring Diagram .....................................................455
Diagnostic Procedure ...........................................456
DTC P1271, P1281 A/F SENSOR 1 .......................459
Component Description ........................................459
CONSULT-II Reference Value in Data Monitor Mode
.459
On Board Diagnosis Logic ....................................459
DTC Confirmation Procedure ...............................459
Wiring Diagram .....................................................461
Diagnostic Procedure ...........................................464
Removal and Installation ......................................467
DTC P1272, P1282 A/F SENSOR 1 .......................468
Component Description ........................................468
CONSULT-II Reference Value in Data Monitor Mode
.468
On Board Diagnosis Logic ....................................468
DTC Confirmation Procedure ...............................468
Wiring Diagram .....................................................470
Diagnostic Procedure ...........................................473
Removal and Installation ......................................476
DTC P1273, P1283 A/F SENSOR 1 .......................477
Component Description ........................................477
CONSULT-II Reference Value in Data Monitor Mode
.477
On Board Diagnosis Logic ....................................477
DTC Confirmation Procedure ...............................477
Wiring Diagram .....................................................479
Diagnostic Procedure ...........................................482
Removal and Installation ......................................486
DTC P1274, P1284 A/F SENSOR 1 .......................487
Component Description ........................................487
CONSULT-II Reference Value in Data Monitor Mode
.487
On Board Diagnosis Logic ....................................487
DTC Confirmation Procedure ...............................487
Wiring Diagram .....................................................489
Diagnostic Procedure ...........................................492
Removal and Installation ......................................496
DTC P1276, P1286 A/F SENSOR 1 .......................497
Component Description ........................................497
CONSULT-II Reference Value in Data Monitor Mode
.497
On Board Diagnosis Logic ....................................497
DTC Confirmation Procedure ...............................497
Overall Function Check ........................................498
Wiring Diagram .....................................................500
Diagnostic Procedure ...........................................503
Removal and Installation ......................................506
DTC P1278, P1288 A/F SENSOR 1 .......................507
Component Description ........................................507
CONSULT-II Reference Value in Data Monitor Mode
.507
On Board Diagnosis Logic ....................................507
DTC Confirmation Procedure ...............................508
Wiring Diagram .....................................................510
Diagnostic Procedure ...........................................513
Removal and Installation ......................................518

EC-258Revision: October 2005
DTC P0181 FTT SENSOR
2005 QX56
Component InspectionUBS00H39
FUEL TANK TEMPERATURE SENSOR
1. Remove fuel level sensor unit.
2. Check resistance between “fuel level sensor unit and fuel pump”
terminals 3 and 4 by heating with hot water or heat gun as
shown in the figure.
Removal and InstallationUBS00H3A
FUEL TANK TEMPERATURE SENSOR
Refer to FL-5, "FUEL LEVEL SENSOR UNIT, FUEL FILTER AND FUEL PUMP ASSEMBLY" .
Temperature °C (°F) Resistance kΩ
20 (68) 2.3 - 2.7
50 (122) 0.79 - 0.90
SEF 4 76 YA

DTC P0182, P0183 FTT SENSOR
EC-263
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Revision: October 20052005 QX56
Component InspectionUBS00H3G
FUEL TANK TEMPERATURE SENSOR
1. Remove fuel level sensor unit.
2. Check resistance between “fuel level sensor unit and fuel pump”
terminals 3 and 4 by heating with hot water or heat gun as
shown in the figure.
Removal and InstallationUBS00H3H
FUEL TANK TEMPERATURE SENSOR
Refer to FL-5, "FUEL LEVEL SENSOR UNIT, FUEL FILTER AND FUEL PUMP ASSEMBLY" .
Temperature °C (°F) Resistance kΩ
20 (68) 2.3 - 2.7
50 (122) 0.79 - 0.90
SEF 4 76 YA

DTC P0300 - P0308 MULTIPLE CYLINDER MISFIRE, NO. 1 - 8 CYLINDER MIS-
FIRE
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Revision: October 20052005 QX56
DTC P0300 - P0308 MULTIPLE CYLINDER MISFIRE, NO. 1 - 8 CYLINDER MIS-
FIRE
PFP:00000
On Board Diagnosis LogicUBS00L0T
When a misfire occurs, engine speed will fluctuate. If the engine speed fluctuates enough to cause the crank-
shaft position (CKP) sensor (POS) signal to vary, ECM can determine that a misfire is occurring.
The misfire detection logic consists of the following two conditions.
1. One Trip Detection Logic (Three Way Catalyst Damage)
On the 1st trip that a misfire condition occurs that can damage the three way catalyst (TWC) due to over-
heating, the MIL will blink.
When a misfire condition occurs, the ECM monitors the CKP sensor signal every 200 engine revolutions
for a change.
When the misfire condition decreases to a level that will not damage the TWC, the MIL will turn off.
If another misfire condition occurs that can damage the TWC on a second trip, the MIL will blink.
When the misfire condition decreases to a level that will not damage the TWC, the MIL will remain on.
If another misfire condition occurs that can damage the TWC, the MIL will begin to blink again.
2. Two Trip Detection Logic (Exhaust quality deterioration)
For misfire conditions that will not damage the TWC (but will affect vehicle emissions), the MIL will only
light when the misfire is detected on a second trip. During this condition, the ECM monitors the CKP sen-
sor signal every 1,000 engine revolutions.
A misfire malfunction can be detected on any one cylinder or on multiple cylinders.
DTC Confirmation ProcedureUBS00L0U
CAUTION:
Always drive vehicle in safe manner according to traffic conditions and obey all traffic laws when driv-
ing.
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
Sensor Input signal to ECM ECM function
Crankshaft position sensor (POS) Engine speed On board diagnosis of misfire
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0300
0300Multiple cylinder misfire
detectedMultiple cylinder misfire.

Improper spark plug

Insufficient compression

Incorrect fuel pressure

The injector circuit is open or shorted

Fuel injector

Intake air leak

The ignition signal circuit is open or
shorted

Lack of fuel

Signal plate

Air fuel ratio (A/F) sensor 1

Incorrect PCV hose connection P0301
0301No.1 cylinder misfire
detectedNo. 1 cylinder misfires.
P0302
0302No. 2 cylinder misfire
detectedNo. 2 cylinder misfires.
P0303
0303No. 3 cylinder misfire
detectedNo. 3 cylinder misfires.
P0304
0304No. 4 cylinder misfire
detectedNo. 4 cylinder misfires.
P0305
0305No. 5 cylinder misfire
detectedNo. 5 cylinder misfires.
P0306
0306No. 6 cylinder misfire
detectedNo. 6 cylinder misfires.
P0307
0307No. 7 cylinder misfire
detectedNo. 7 cylinder misfires.
P0308
0308No. 8 cylinder misfire
detectedNo. 8 cylinder misfires.

DTC P1217 ENGINE OVER TEMPERATURE
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Revision: October 20052005 QX56
On Board Diagnosis LogicUBS00H8V
If the cooling fan or another component in the cooling system malfunctions, engine coolant temperature will
rise.
When the engine coolant temperature reaches an abnormally high temperature condition, a malfunction is
indicated.
This self-diagnosis has the one trip detection logic.
CAUTION:
When a malfunction is indicated, be sure to replace the coolant. Refer to CO-10, "
Changing Engine
Coolant" . Also, replace the engine oil. Refer to LU-8, "Changing Engine Oil" .
1. Fill radiator with coolant up to specified level with a filling speed of 2 liters per minute. Be sure to
use coolant with the proper mixture ratio. Refer to MA-12, "
ANTI-FREEZE COOLANT MIXTURE
RATIO" .
2. After refilling coolant, run engine to ensure that no water-flow noise is emitted.
Overall Function CheckUBS00H8W
Use this procedure to check the overall function of the cooling fan. During this check, a DTC might not be con-
firmed.
WA RN ING:
Never remove the radiator cap when the engine is hot. Serious burns could be caused by high pres-
sure fluid escaping from the radiator.
Wrap a thick cloth around cap. Carefully remove the cap by turning it a quarter turn to allow built-up
pressure to escape. Then turn the cap all the way off.
WITH CONSULT-II
1. Check the coolant level in the reservoir tank and radiator.
Allow engine to cool before checking coolant level.
If the coolant level in the reservoir tank and/or radiator is below
the proper range, skip the following steps and go to EC-445,
"Diagnostic Procedure" .
2. Confirm whether customer filled the coolant or not. If customer
filled the coolant, skip the following steps and go to EC-445,
"Diagnostic Procedure" .
3. Turn ignition switch ON.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1217
1217Engine over tempera-
ture (Overheat)

Cooling fan does not operate properly (Over-
heat).

Cooling fan system does not operate prop-
erly (Overheat).

Engine coolant was not added to the system
using the proper filling method.

Engine coolant is not within the specified
range.

Harness or connectors
(The cooling fan circuit is open or
shorted.)

Cooling fan

IPDM E/R (Cooling fan relay)

Radiator hose

Radiator

Radiator cap

Water pump

Thermostat
For more information, refer to EC-448,
"Main 12 Causes of Overheating" .
SEF 6 21 W

DTC P1217 ENGINE OVER TEMPERATURE
EC-447
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Revision: October 20052005 QX56
8. CHECK MAIN 12 CAUSES
If the cause cannot be isolated, go to EC-448, "
Main 12 Causes of Overheating" .
>>INSPECTION END
PROCEDURE A
1. CHECK POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect IPDM E/R harness connector E120.
3. Check voltage between IPDM E/R terminal 22 and ground with
CONSULT-II or tester.
OK or NG
OK >> GO TO 3.
NG >> GO TO 2.
2. DETECT MALFUNCTIONING PART
Check the following.

40A fusible link

Harness for open or short between IPDM E/R and battery
>> Repair open circuit or short to ground or short to power in harness or connectors.
3. CHECK COOLING FAN MOTOR CIRCUIT FOR OPEN OR SHORT
1. Disconnect cooling fan motor harness connector.
2. Check harness continuity between cooling fan motor terminal 1
and IPDM E/R terminal 24, cooling fan motor terminal 2 and
ground.
Refer to wiring diagram.
3. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power
in harness or connectors.
4. CHECK COOLING FAN MOTOR
Refer to EC-449, "
Component Inspection" .
OK or NG
OK >> GO TO 5.
NG >> Replace cooling fan motor.Voltage: Battery voltage
PBIB2067E
Continuity should exist.
BBIA0446E