2006 INFINITI QX56 heater

ATC-186
REFRIGERANT LINES
Revision: November 20092006 QX56
REMOVAL
1. Remove the rear heater and cooling unit assembly from the vehicle. Refer to ATC-155, "REAR HEATER
AND COOLING UNIT ASSEMBLY" .
2. Remove the rear blower motor.
3. Remove the rear blower speed resistor.
4. Remove the rear air mix door motor.
5. Remove the rear duct and blend door assembly. Refer to AT C -
170, "REAR OVERHEAD DUCTS" .
6. Disassemble the rear heater and cooling unit assembly to remove the evaporator.
INSTALLATION
Installation is in the reverse order of removal.
CAUTION:

Replace the O-rings on the rear A/C pipes with new ones. Apply compressor oil to the O-rings
when installing them.

After charging refrigerant, check for leaks.
Removal and Installation for Front Expansion ValveEJS003Z3
REMOVAL
1. Discharge the refrigerant. Refer to ATC-171, "HFC-134a (R-134a) Service Procedure" .
2. Remove the front evaporator. Refer to ATC-184, "
Removal and Installation for Front Evaporator" .
3. Remove the cooler grommet.
4. Remove the expansion valve.
INSTALLATION
Installation is in the reverse order of removal.
CAUTION:

Replace the O-rings on the A/C refrigerant pipes with new ones, then apply compressor oil to them
when installing them.

After charging refrigerant, check for leaks.
Removal and Installation for Rear Expansion ValveEJS003Z4
REMOVAL
1. Discharge the refrigerant. Refer to ATC-171, "HFC-134a (R-134a) Service Procedure" .
2. Remove the luggage side lower finisher RH. Refer to EI-40, "
LUGGAGE FLOOR TRIM" .
3. Disconnect the A/C refrigerant pipes from the expansion valve.
LJIA0021E
WJIA0582E
Expansion valve bolts : 4 N·m (0.41 kg-m, 35 in-lb)
A/C refrigerant pipe to expansion valve bolt : Refer to ATC-173, "
Components"
.

REFRIGERANT LINESATC-189
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AT C
Revision: November 2009 2006 QX56
2. When checking for leaks, circle each fitting completely with the
probe as shown.
3. Move the probe along each component at a speed of approxi- mately 25 - 50 mm (1 - 2 in)/second as shown.
CHECKING PROCEDURE
NOTE:
To prevent inaccurate or false readings, make sure there is no refrigerant vapor, shop chemicals, or cigarette
smoke in the vicinity of the vehicle. Perform the leak test in a calm area (low air/wind movement) so that the
leaking refrigerant is not dispersed.
1. Turn the engine OFF.
2. Connect the manifold gauge set (J-39183-C) to the A/C service ports. Refer to ATC-171, "
SETTING OF
SERVICE TOOLS AND EQUIPMENT" .
3. Check if the A/C refrigerant pressure is at least 345 kPa (3.52 kg/cm
2 , 50 psi) above a temperature of
16 °C (61 °F). If less than specification, recover/evacuate and recharge the system with the specified
amount of refrigerant. Refer to ATC-171, "
HFC-134a (R-134a) Service Procedure" .
NOTE:
At temperatures below 16 °C (61 °F), leaks may not be detected since the system may not reach 345 kPa
(3.52 kg/cm
2 , 50 psi) pressure.
4. Perform the leak test from the high-pressure side (front A/C compressor discharge “a” to evaporator inlet
“f ” or rear piping connection “l”) to the low-pressure side (front A/C evaporator drain hose “g” to shaft seal
“k ” and rear A/C evaporator drain hose “o ” to piping connection “r”). Refer to ATC-173, "
Components" .
Clean the component to be checked and carefully move the electronic refrigerant leak detector probe
completely around the following connections and components.

Check the compressor shaft seal

Check the high and low-pressure pipe and hose fittings, relief valve, and compressor shaft seal

Check the liquid tank

Check the refrigerant pressure sensor

Check all around the service valves. Check that the service valve caps are screwed tightly on the ser-
vice valves (to prevent leaks).
NOTE:
After removing manifold gauge set (J-39183-C) from the service valves, wipe any residue from the ser-
vice valves to prevent any false readings by the electronic refrigerant leak detector (J-41995).

Evaporator
With engine OFF, turn blower fan on “High” for at least 15 seconds to dissipate any refrigerant trace in
the heater and cooling unit assembly. Wait a minimum of 10 minutes accumulation time (refer to the
manufacturer's recommended procedure for actual wait time) before inserting the electronic refrigerant
leak detector probe into the heater and cooling unit assembly drain hose.
SHA706E
SHA708EA

ATC-190
REFRIGERANT LINES
Revision: November 20092006 QX56
NOTE:
Keep the probe inserted for at least 10 seconds. Use caution not to contaminate the probe tip with
water or dirt that may be in the drain hose.
5. If a leak is detected, verify at least once by blowing compressed air into the area of the suspected leak, then repeat the leak check.
6. Do not stop when one leak is found. Continue to check for additional leaks at all system components and connections.
7. If no leaks are found, perform steps 8 - 11.
8. Start the engine.
9. Set the heater A/C controls as follows:
NOTE:
For the automatic system, turn OFF the automatic controls and set the heater A/C controls manually.
a. A/C switch to ON
b. Air flow to VENT mode
c. Intake position to RECIRCULATION mode
d. Temperature to MAX cold
e. Blower fan speed to HIGH
10. Run the engine at 1,500 rpm for at least 2 minutes.
11. Turn the engine OFF and perform the leak check again following steps 4 through 6 above.
Refrigerant leaks should be checked immediately after turning
the engine OFF. Begin with the leak detector at the compressor.
The pressure on the high pressure side will gradually drop after
the refrigerant circulation stops and pressure on the low pres-
sure side will gradually rise, as shown in the graph. Some leaks
are more easily detected when the pressure is high.
12. Before connecting the recovery/recycling equipment to the vehicle, check the recovery/recycling equip- ment gauges. No refrigerant pressure should be displayed. If pressure is displayed, recover the refriger-
ant from the equipment lines and then check the refrigerant purity.
13. Confirm refrigerant purity in supply tank using recovery/recycling equipment and refrigerant identifier equipment (J-41810-NI).
14. Confirm the refrigerant purity in the vehicle's A/C system using recovery/recycling equipment and refriger- ant identifier equipment (J-41810-NI).
15. Discharge the A/C system using recovery/recycling equipment. Repair the leaking fitting or component as necessary.
16. Evacuate and recharge the A/C system and perform the leak test to confirm that there are no refrigerant leaks.
17. Conduct the Operational Check to ensure system works properly. Refer to AT C - 5 8 , "
Operational Check
(Front)" and AT C - 6 0 , "Operational Check (Rear)" .
SHA839E

AV-34
AUDIO
Revision: November 20092006 QX56
Occurrence conditionPossible cause
Occurs only when engine is ON. A continuous growling noise occurs. The speed of
the noise varies with changes in the engine speed.

Ignition components
A whistling noise occurs while the engine speed is
high. A booming noise occurs while the engine is
running and the lighting switch is ON.

Generator
The occurrence of the noise is linked with the operation of the fuel pump.

Fuel pump condenser
Noise only occurs when various
electrical components are oper-
ating. A cracking or snapping sound occurs with the
operation of various switches.

Relay malfunction, audio unit malfunction
The noise occurs when various motors are operat-
ing.

Motor case ground

Motor
The noise occurs constantly, not just under certain conditions.

Rear defogger coil malfunction

Open circuit in printed heater

Poor ground of antenna amplifier or
antenna feeder line
A cracking or snapping sound occurs while the vehicle is being driven, especially
when it is vibrating excessively.

Ground wire of body parts

Ground due to improper part installation

Wiring connections or a short circuit

ENGINE COOLANTCO-11
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Revision: November 2009 2006 QX56
DRAINING ENGINE COOLANT
1. Turn ignition switch ON and set temperature control lever all the way to HOT position or the highest tem-
perature position. Wait 10 seconds and turn ignition switch OFF.
2. Remove the engine front undercover using power tool.
3. Open the radiator drain plug at the bottom of the radiator, and remove the radiator filler cap. This is the only step required
when partially draining the cooling system (radiator only).
CAUTION:
Do not to allow the coolant to contact the drive belts.
4. When draining all of the coolant in the system for engine removal or repair, it is necessary to drain the cylinder block.
Remove the RH cylinder block drain plug to drain the right bank
and the oil cooler hose to drain the left bank as shown.
5. Remove the reservoir tank to drain the engine coolant, then clean the reservoir tank before installing it.
6. Check the drained coolant for contaminants such as rust, corrosion or discoloration. If the coolant is contaminated, flush the engine cooling system. Refer to CO-12, "
FLUSHING COOLING
SYSTEM" .
REFILLING ENGINE COOLANT
1. Close the radiator drain plug. Install the reservoir tank, cylinder block drain plug, and the oil cooler hose, if
removed for a total system drain or for engine removal or repair.

The radiator must be completely empty of coolant and water.

Apply sealant to the threads of the cylinder block drain plug. Use Genuine High Performance Thread
Sealant or equivalent. Refer to GI-46, "
Recommended Chemical Products and Sealants" .
2. Set the vehicle heater controls to the full HOT and heater ON position. Turn the vehicle ignition ON with the engine OFF as necessary to activate the heater mode.
3. Remove the vented reservoir cap and replace it with a non-vented reservoir cap before filling the cooling system.
WBIA0391E
PBIC0146E
WBIA0392E
Radiator drain plug : Refer to CO-14, "RADIATOR" .
RH cylinder block drain plug : Refer to EM-78, "
CYLINDER BLOCK" .

THERMOSTAT AND WATER PIPINGCO-21
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Revision: November 2009 2006 QX56
THERMOSTAT AND WATER PIPINGPFP:21200
Removal and InstallationEBS00REG
REMOVAL
Removal of Thermostat
1. Drain engine coolant from the radiator. Refer to CO-11, "DRAINING ENGINE COOLANT" .
CAUTION:
Perform when engine is cold.
2. Remove the air duct and resonator assembly. Refer to EM-15, "
Removal and Installation" .
3. Remove the engine room cover using power tool.
4. Disconnect the water suction hose from the water inlet.
5. Remove the water inlet and thermostat.
Removal of Thermostat Housing, Water Outlet and Heater Pipe
1. Remove the intake manifold. Refer to EM-17, "Removal and Installation" .
2. Remove the thermostat housing, water outlet and heater pipe.
Removal of Water Cut Valve
1. Drain the engine coolant from the radiator. Refer to CO-11, "DRAINING ENGINE COOLANT" .
KBIA2501E
1. Heater pipe2. Gasket 3. Water outlet
4. Gasket 5.O-ring 6.O-ring
7. Thermostat housing 8. Rubber ring 9. Thermostat
10. Water inlet 11. Water suction hose 12. Water suction pipe
13. Gasket 14. Heater pipe

CO-22Revision: November 2009
THERMOSTAT AND WATER PIPING
2006 QX56
CAUTION:
Perform when the engine is cold.
2. Remove the air duct and resonator assembly. Refer to EM-15, "
Removal and Installation" .
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.
SLC252B
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-2Revision: November 20092006 QX56
Description ...........................................................
.144
Diagnostic Procedure .......................................... .144
POWER SUPPLY AND GROUND CIRCUIT .......... .145
Wiring Diagram .................................................... .145
Diagnostic Procedure .......................................... .146
Ground Inspection ............................................... .150
DTC U1000, U1001 CAN COMMUNICATION LINE .151
Description ........................................................... .151
On Board Diagnosis Logic ................................... .151
DTC Confirmation Procedure .............................. .151
Wiring Diagram .................................................... .152
Diagnostic Procedure .......................................... .153
DTC U1010 CAN COMMUNICATION .................... .154
Description ........................................................... .154
On Board Diagnosis Logic ................................... .154
DTC Confirmation Procedure .............................. .154
Diagnostic Procedure .......................................... .155
DTC P0031, P0032, P0051, P0052 A/F SENSOR 1
HEATER ................................................................. .156
Description ........................................................... .156
CONSULT-II Reference Value in Data Monitor Mode .156
On Board Diagnosis Logic ................................... .156
DTC Confirmation Procedure .............................. .156
Wiring Diagram .................................................... .157
Diagnostic Procedure .......................................... .160
Component Inspection ......................................... .162
Removal and Installation ..................................... .162
DTC P0037, P0038, P0057, P0058 HO2S2 HEATER .163
Description ........................................................... .163
CONSULT-II Reference Value in Data Monitor Mode .163
On Board Diagnosis Logic ................................... .163
DTC Confirmation Procedure .............................. .164
Wiring Diagram .................................................... .165
Diagnostic Procedure .......................................... .168
Component Inspection ......................................... .170
Removal and Installation ..................................... .170
DTC P0101 MAF SENSOR .................................... .171
Component Description ....................................... .171
CONSULT-II Reference Value in Data Monitor Mode .171
On Board Diagnosis Logic ................................... .171
DTC Confirmation Procedure .............................. .172
Overall Function Check ....................................... .173
Wiring Diagram .................................................... .174
Diagnostic Procedure .......................................... .175
Component Inspection ......................................... .178
Removal and Installation ..................................... .179
DTC P0102, P0103 MAF SENSOR ........................ .180
Component Description ....................................... .180
CONSULT-II Reference Value in Data Monitor Mode .180
On Board Diagnosis Logic ................................... .180
DTC Confirmation Procedure .............................. .181
Wiring Diagram .................................................... .182
Diagnostic Procedure .......................................... .183
Component Inspection ......................................... .186
Removal and Installation ..................................... .187DTC P0112, P0113 IAT SENSOR ...........................
.188
Component Description ....................................... .188
On Board Diagnosis Logic ................................... .188
DTC Confirmation Procedure ............................... .188
Wiring Diagram .................................................... .189
Diagnostic Procedure ........................................... .190
Component Inspection ......................................... .191
Removal and Installation ...................................... .191
DTC P0117, P0118 ECT SENSOR ......................... .192
Component Description ....................................... .192
On Board Diagnosis Logic ................................... .192
DTC Confirmation Procedure ............................... .193
Wiring Diagram .................................................... .194
Diagnostic Procedure ........................................... .195
Component Inspection ......................................... .196
Removal and Installation ...................................... .197
DTC P0122, P0123 TP SENSOR ........................... .198
Component Description ....................................... .198
CONSULT-II Reference Value in Data Monitor Mode .198
On Board Diagnosis Logic ................................... .198
DTC Confirmation Procedure ............................... .199
Wiring Diagram .................................................... .200
Diagnostic Procedure ........................................... .201
Component Inspection ......................................... .204
Removal and Installation ...................................... .204
DTC P0125 ECT SENSOR ..................................... .205
Component Description ....................................... .205
On Board Diagnosis Logic ................................... .205
DTC Confirmation Procedure ............................... .206
Diagnostic Procedure ........................................... .206
Component Inspection ......................................... .207
Removal and Installation ...................................... .207
DTC P0127 IAT SENSOR ....................................... .208
Component Description ....................................... .208
On Board Diagnosis Logic ................................... .208
DTC Confirmation Procedure ............................... .208
Diagnostic Procedure ........................................... .209
Component Inspection ......................................... .210
Removal and Installation ...................................... .210
DTC P0128 THERMOSTAT FUNCTION ................ .211
On Board Diagnosis Logic ................................... .211
DTC Confirmation Procedure ............................... .211
Diagnostic Procedure ........................................... .211
Component Inspection ......................................... .212
Removal and Installation ...................................... .212
DTC P0130, P0150 A/F SENSOR 1 ....................... .213
Component Description ....................................... .213
CONSULT-II Reference Value in Data Monitor Mode .213
On Board Diagnosis Logic ................................... .213
DTC Confirmation Procedure ............................... .213
Overall Function Check ........................................ .214
Wiring Diagram .................................................... .216
Diagnostic Procedure ........................................... .219
Removal and Installation ...................................... .222
DTC P0131, P0151 A/F SENSOR 1 ....................... .223
Component Description ....................................... .223
CONSULT-II Reference Value in Data Monitor Mode