GI-14
< HOW TO USE THIS MANUAL >
ABBREVIATIONS
E
F
G
H
ABBREVIATION DESCRIPTION E/T Exhaust temperature
EBD Electric brake force distribution EC Engine control
ECL Engine coolant level
ECM Engine control module ECT Engine coolant temperature
ECV Electrical control valve
EEPROM Electrically erasable pr ogrammable read only memory
EFT Engine fuel temperature
EGR Exhaust gas recirculation
EGRT Exhaust gas recirculation temperature EGT Exhaust gas temperature
EOP Engine oil pressure EP Exhaust pressure
EPR Exhaust pressure regulator EPS Electronically cont rolled power steering
ESP Electronic stability program system
EVAP canister Evaporative emission canister EVSE Electric vehicle supply equipmentEXC Exhaust control
ABBREVIATION DESCRIPTION FC Fan control
FCW Forward collision warning FIC Fuel injector controlFP Fuel pump
FR Front
FRP Fuel rail pressure
FRT Fuel rail temperatureFTP Fuel tank pressure FTT Fuel tank temperature
ABBREVIATION DESCRIPTION GND GroundGPS Global positioning systemGST Generic scan tool
ABBREVIATION DESCRIPTION HBMC Hydraulic body-motion control systemHDD Hard disk drive
HO2S Heated oxygen sensor HOC Heated oxidation catalyst
HPCM Hybrid power train control module
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HEATING AND COOLING UNIT ASSEMBLYHA-41
< REMOVAL AND INSTALLATION >
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HEATING AND COOLING UNIT ASSEMB LY : Removal and InstallationINFOID:0000000009463949
REMOVAL
1. Discharge the refrigerant. Refer to HA-23, "Recycle Refrigerant".
2. Drain the cooling system. Refer to CO-12, "Changing Engine Coolant"
.
3. Remove the instrument panel assembly. Refer to IP-15, "Removal and Installation"
.
4. Remove the steering column. Refer to ST-33, "Removal and Installation"
.
5. Remove the strut tower brace. Refer to FSU-19, "Exploded View"
.
6. Disconnect the low-pressure pipe from the expansion valve. CAUTION:
Cap or wrap the joint of the pipe with suitable ma terial such as vinyl tape to avoid the entry of air.
7. Disconnect the high-pressure pi pe from the expansion valve.
8. Disconnect the heater hoses from the heater core pipes.
9. Remove the steering member cover (A) and bolt (B). NOTE:
The steering member cover (A) and bolt (B) can be found near
the cowl area in the engine compartment.
10. Remove the remaining steering member bolts.
11. Disconnect the harness connectors from the heati ng and cooling unit assembly and steering member.
12. Remove the heating and cooling unit assembly and steering member as one assembly from the vehicle.
13. Seperate the heating and cooling unit assembly from the steering member.
INSTALLATION
Installation is in the reverse order of removal.
CAUTION:
After charging refrigerant, check for leaks. Refer to HA-21, "Leak Test"
.
HEATER CORE
1. Heating and cooling unit assembly 2. Steering member Front
ALIIA0624ZZ
ALIIA0623ZZ
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COMPONENT PARTSHAC-11
< SYSTEM DESCRIPTION > [AUTOMATIC AIR CONDITIONER]
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Air mix door motor RH The air mix door controls the mix of hot or cold air that enters the ventilation system. It is controlled
by the A/C auto amp. based on the position of the temperature dial. The air mix door motor RH re-
ceives position commands from the A/C auto amp. and reports actual door position back via an LCU
(Local Control Unit) installed inside the motor. Commands and responses are sent across the LIN (Lo-
cal Interconnect Network) to each motor simultaneously, with each motor having its own unique ad-
dress, thereby only responding to requests sent to its specific address. The LCU reads the door
position from a Position Balanced Resistor (PBR), also part of the motor, and returns that information
to the A/C auto amp. The LCU switches the polarity of the circuits connected to the DC motor to drive
the motor forward or backward as requested by the A/C auto amp. If the air mix door moves to a po-
sition less than 5% or more than 95% of its expected or allowed positions, the A/C auto amp. will set
a DTC.
Ambient sensor The ambient sensor measures the temperature of the air surrounding the vehicle. The sensor uses a
thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor
decreases as temperature increases.
BCM The BCM receives the fan ON and A/C ON signals from the A/C auto amp. and sends a compressor
ON request to the ECM.
Blower motor The blower motor varies the speed at which the air flows through the ventilation system.
ECM The ECM sends a compressor ON request to the IPDM E/R based on the status of engine operation
and load as well as refrigerant pressure information. If all the conditions are met for A/C operation,
the ECM transmits the compressor ON request to the IPDM E/R. The ECM shares the refrigerant
pressure sensor signal, engine RPM, and engine coolant temperature with the A/C auto amp. via
CAN communication line.
Front blower motor relay The front blower motor relay controls the flow of current to fuse 17 and 27 in the Fuse Block (J/B).
The relay is connected directly to ground, and is energized when the ignition switch is in the ON or
START position.
Fuse Block (J/B) Located in the passenger compartment, behind the left lower IP, the Fuse Block (J/B) contains the
front blower motor relay and several fuses required for the air conditioner control system.
Intake door motor The intake door motor controls the position of the intake door. Fresh air is allowed to enter the cabin
in one position, and recirculated inside air is allowed to enter in the other position. At times the A/C
auto amp. may command partial fresh or recirculation based on evaporator or coolant temperatures.
The intake door motor receives position commands from the A/C auto amp. and reports actual door
position back via an LCU (Local Control Unit) installed inside the motor. Commands and responses
are sent across the LIN (Local Interconnect Network) to each motor simultaneously, with each motor
having its own unique address, thereby only responding to requests sent to its specific address. The
LCU reads the door position from a Position Balanced Resistor (PBR), also part of the motor, and re-
turns that information to the A/C auto amp. The LCU switches the polarity of the circuits connected to
the DC motor to drive the motor forward or backward as requested by the A/C auto amp. If the recir-
culation door moves to a position less than 5% or more than 95% of its expected or allowed positions,
the A/C auto amp. will set a DTC.
Intake sensor The intake sensor measures the temperature of the front evaporator fins. The sensor uses a ther-
mistor which is sensitive to the change in temperature. The electrical resistance of the thermistor de-
creases as temperature increases.
In-vehicle sensor In-vehicle sensor measures temperature of intake air that flows through aspirator to passenger room.
The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resis-
tance of the thermistor decreases as temperature increases.
IPDM E/R Refer to PCS-6, "RELAY CONTROL SYSTEM : System Description"
.
Mode door motor The mode door controls the direction the conditioned air passes through the ventilation system.
Through a series of levers and gears, the mode door controls the defrost door, the foot door, and the
vent door. There are 5 preset positions: VENT, B/L, FOOT, D/F, and DEF. The FOOT position can be
set to allow some airflow through to the defroster vent, or to completely block the defroster vent using
the CONSULT. The mode door motor receives position commands from the A/C auto amp. and re-
ports actual door position back via an LCU (Local Control Unit) installed inside the motor. Commands
and responses are sent across the LIN (Local Interconnect Network) to each motor simultaneously,
with each motor having its own unique address, thereby only responding to requests sent to its spe-
cific address. The LCU reads the door position from a Position Balanced Resistor (PBR), also part of
the motor, and returns that information to the A/C auto amp. The LCU switches the polarity of the cir-
cuits connected to the DC motor to drive the motor forward or backward as requested by the A/C auto
amp. The mode door has 5 expected positions and, therefore, can set up to 5 DTCs if the expected
position is not reported back to the A/C auto amp.
Component Description
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SYSTEMHAC-15
< SYSTEM DESCRIPTION > [AUTOMATIC AIR CONDITIONER]
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• When air outlet is VENT or B/L, the minimum air flow is changed depending on sunload.
STARTING AIR FLOW CONTROL
• When blower motor is activated, A/C auto amp. graduallyincreases duty ratio of blower motor control signal to prevent a
sudden increase in discharge air flow.
• It takes approximately 8 seconds for air flow to reach HI from LOW.
LOW COOLANT TEMPERATURE STARTING CONTROL
If the engine coolant temperature is 56 °C (133 °F) or less, to prevent
a cold discharged air flow, A/C auto amp. suspends blower motor
activation for a maximum of 150 seconds depending on target air
mix door opening angle. After this, blower motor control signal is
increased gradually, and blower motor is activated.
HIGH IN-VEHICLE TEMPERATURE STARTING CONTROL
When front evaporator fin temperature is high [intake sensor value is 35°C (95 °F) or more], to prevent a hot
discharged air flow, A/C auto amp. suspends blower moto r activation for approximately 3 seconds so that front
evaporator is cooled by refrigerant.
FAN SPEED CONTROL AT DOOR MOTOR OPERATION
When mode door motor is activated while air flow is more than the specified value, A/C auto amp. reduces fan
speed temporarily so that mode door moves smoothly.
Air Inlet ControlINFOID:0000000009463096
The intake door is automatically controlled by the temperature set-
ting, ambient temperature, in-vehicle temperature, intake tempera-
ture, amount of sunload and ON/OFF operation of the compressor.
Intake door automatic control selects FRE, 20% FRE, or REC
depending on a target air mix door opening angle, based on in-vehi-
cle temperature, ambient temperature, and sunload.
JMIIA0735GB
JMIIA0736GB
JMIIA0737GB
JMIIA0732GB
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM
HAC-16
< SYSTEM DESCRIPTION >[AUTOMATIC AIR CONDITIONER]
SYSTEM
Air Outlet Control
INFOID:0000000009463097
• While air outlet is in automatic control, A/C auto amp. selects the mode door position depending on a target air mix door angle and
outlet air temperature calculated from sunload.
• If ambient temperature is excessively low, D/F is selected to pre- vent windshield fogging when air outlet is set to FOOT.
Compressor ControlINFOID:0000000009463098
DESCRIPTION
• When the compressor activation condition is satisfied whil e blower motor is activated, A/C auto amp. trans-
mits A/C ON signal and blower fan ON signal to ECM via CAN communication.
• ECM judges that the compressor can be activated depending on the state of each sensor (refrigerant pres-
sure sensor signal and others) and transmits A/C comp ressor request signal to IPDM E/R via CAN commu-
nication.
• IPDM E/R turns A/C relay ON and activate s the compressor depending on request from ECM.
COMPRESSOR PROTECTION CONTROL AT PRESSURE MALFUNCTION
When high-pressure side value that is detected by refrigerant pressure sensor is as per the following state,
ECM requests IPDM E/R to turn A/C relay OFF and stops the compressor.
• 3.12 MPa (31.82 kg/cm
2, 452.4 psi) or more (When the engine speed is less than 1,500 rpm)
• 2.74 MPa (27.95 kg/cm
2, 397.3 psi) or more (When the engine speed is 1,500 rpm or more)
• 0.14 MPa (1.43 kg/cm
2, 20.3 psi) or less
COMPRESSOR OIL CIRCULATION CONTROL
When the engine starts while the engine coolant temperature is 56 °C (133 °F) or less, ECM activates the com-
pressor for approximately 6 seconds and circulates the compressor lubricant once.
LOW TEMPERATURE PROTECTION CONTROL
• When intake sensor detects that front evaporator fin temperature is 2.5 °C (37 °F) or less, A/C auto amp. requests ECM to turn com-
pressor OFF, and stops the compressor.
• When the front evaporator fin temperature returns to 5.0 °C (41 °F)
or more, the compressor is activated.
OPERATING RATE CONTROL
When set temperature is other than fully cold or air out let is “VENT”, “B/L” or “FOOT” A/C auto amp. controls
the compressor activation depending on ambient temperature.
AIR CONDITIONING CUT CONTROL
When set engine is running is excessively high load conditi on, ECM requests IPDM E/R to turn A/C relay OFF,
and stops the compressor. Refer to EC-56, "AIR CONDITIONING CUT CONT ROL : System Description (with
automatic air conditioner)" (QR25DE) or EC-573, "AIR CONDITIONING CUT CONTROL : System Descrip-
tion" (VQ35DE) for details.
JMIIA0730GB
JMIIA0742GB
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HAC-20
< SYSTEM DESCRIPTION >[AUTOMATIC AIR CONDITIONER]
SYSTEM
Temperature Control
INFOID:0000000009463100
• When ignition switch is in the ON position, A/C auto amp. always automatically controls temperatur e regardless of front air condi-
tioning operational state.
• A/C auto amp. calculates the target air mix door opening angle depending on set temperature, in-vehicle temperature, ambient
temperature, and sunload.
• Air mix door is controlled depending on the comparison of current
air mix door opening angle and target air mix door opening angle.
• Regardless of in-vehicle temperature, ambient temperature, and
sunload, air mix door is fixed at the fully cold position when set
temperature is 18.0 °C (60 °F), and at the fully hot position when set
temperature is 32.0 °C (90 °F).
Fail-safeINFOID:0000000009463101
FAIL-SAFE FUNCTION
If a communication error exists between the A/C auto amp., and the AV control unit and preset switch for 30
seconds or longer, air conditioning is controlled under the following conditions:
When ambient temperature is less than 3 °C (37 °F) and engine coolant temperature is less than 56 °C (133 °F)
When ambient temperature is 3 °C (37 °F) or more, or engine coolant temperature is 56 °C (133 °F) or more
JMIIA0731GB
Compressor : ON
Air outlet : DEF
Air inlet : FRE (Fresh air intake)
Blower fan speed : AUTO
Set temperature : Setting before communication error occurs
Compressor : ON
Air outlet : AUTO
Air inlet : 20% FRE (20% fresh air intake)
Blower fan speed : AUTO
Set temperature : Setting before communication error occurs
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HAC-28
< ECU DIAGNOSIS INFORMATION >[AUTOMATIC AIR CONDITIONER]
A/C AUTO AMP.
ECU DIAGNOSIS INFORMATION
A/C AUTO AMP.
Reference ValueINFOID:0000000009463104
VALUES ON THE DIAGNOSIS TOOL
TERMINAL LAYOUT
PHYSICAL VALUES
Monitor item Condition Value/Status
AMB TEMP SEN Ignition switch ON — 22 - 131 °F ( −30 - 55 °C)
IN-VEH TEMP Ignition switch ON — 22 - 131 °F ( −30 - 55 °C)
INT TEMP SEN Ignition switch ON — 22 - 131 °F ( −30 - 55 °C)
SUNLOAD SEN Ignition switch ON — 0 - 1395 w/m
2
(0 - 1200 kcal/m2·h)
AMB SEN CAL Ignition switch ON — 22 -131 °F ( −30 - 55 °C)
IN-VEH CAL Ignition switch ON — 22 -131 °F ( −30 - 55 °C)
INT TEMP CAL Ignition switch ON — 22 -131 °F ( −30 - 55 °C)
SUNL SEN CAL Ignition switch ON — 0 - 1395 w/m
2
(0 - 1200 kcal/m2·h)
COMP REQ SIG Engine: Run at idle after
warming up A/C switch: ON
(A/C compressor operation
status) On
A/C switch: OFF Off
FAN REQ SIG Engine: Run at idle after
warming up Blower fan: ON On
Blower fan: OFF Off
FAN DUTY Engine: Run at idle after
warming up Blower fan: ON 25 - 85%
Blower fan: OFF 0%
XM Ignition switch ON — −100 - 155
PA TARGET A/TEMP Ignition switch ON — Value according to target air
flow temperature (passen-
ger side)
ENG COOL TEMP Ignition switch ON — Values according to coolant
temperature
VEHICLE SPEED Driving — Equivalent to speedometer
reading
ALIIA0579ZZ
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HAC-98
< SYMPTOM DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
INSUFFICIENT HEATING
INSUFFICIENT HEATING
DescriptionINFOID:0000000009463169
Symptom
• Insufficient heating
• No warm air comes out. (Air flow volume is normal.)
Diagnosis ProcedureINFOID:0000000009463170
NOTE:
Perform self-diagnosis with CONSULT before performing symptom diagnosis. If DTC is detected, perform the
corresponding diagnosis.
1.CHECK COOLING SYSTEM
1. Check engine coolant level and check leakage. Refer to CO-11, "System Inspection"
(QR25DE) or CO-
35, "System Inspection" (VQ35DE).
2. Check reservoir tank cap. Refer to CO-11, "System Inspection"
(QR25DE) or CO-35, "System Inspection"
(VQ35DE).
3. Check water flow sounds of the engine coolant. Refer to CO-11, "System Inspection"
(QR25DE) or CO-
35, "System Inspection" (VQ35DE).
Is the inspection result normal?
YES >> GO TO 2.
NO >> Refill engine coolant and repair or repl ace parts depending on the inspection results.
2.CHECK HEATER HOSE
Check installation of heater hose visually or by touching.
Is the inspection result normal?
YES >> GO TO 3.
NO >> Repair or replace parts depending on the inspection results.
3.CHECK HEATER CORE
1. Check temperature of inlet hose and outlet hose of front heater core.
2. Check that inlet side of heater core is hot and the outle t side is slightly lower than/almost equal to the inlet
side.
CAUTION:
Always perform the temperature in spection in a short period of time because the engine coolant
temperature is very hot.
Is the inspection result normal?
YES >> GO TO 4.
NO >> Replace heater core. Refer to HA-42, "HEATER CORE : Removal and Installation"
.
4.CHECK AIR LEAKAGE FROM EACH DUCT
Check duct and nozzle, etc. of front air conditioning system for air leakage.
Is the inspection result normal?
YES >> GO TO 5.
NO >> Repair or replace parts depending on the inspection results.
5.CHECK SETTING OF TEMPERATURE SETTING TRIMMER (FRONT)
1. Check setting value of temperature setting trimmer (front). Refer to HAC-50, "Temperature Setting Trim-
mer".
2. Check that temperature setting trimmer (front) is set to “ − direction”.
NOTE:
The control temperature can be set by t he temperature setting trimmer (front).
3. Set difference between the set temperature and control temperature to “0”.
Are the symptoms solved?
YES >> Inspection End.
NO >> Replace A/C auto amp. Refer to HAC-102, "Removal and Installation"
.
Revision: November 20132014 Altima NAMRevision: November 20132014 Altima NAM