Nissan Sentra manuals

Nissan Sentra Service Manual: System description

COMPONENT PARTS

Component Part Location



  1. ECM
  2. IPDM E/R
  3. BCM (view with combination meter removed)
  4. A/C auto amp. (view with A/C switch assembly removed)
  5. A/C switch assembly
  6. A/C Compressor
  7. Refrigerant pressure sensor (view with front bumper fascia removed)
  8. Fuse Block (J/B), Front blower motor relay
  9. Blower motor (view with front A/C assembly removed from vehicle)
  10. Mode door motor
  11. Intake door motor
  12. Air mix door motor
  13. Intake sensor
  14. Variable blower control

Component Description

Component

Description

A/C auto amp. A/C auto amp. controls front automatic air conditioning system by inputting and calculating signals from each sensor and each switch.
A/C Compressor Vaporized refrigerant is drawn into the A/C compressor from the evaporator, where it is compressed to a high pressure, high temperature vapor. The hot, compressed vapor is then discharged to the condenser.
A/C switch assembly The A/C switch assembly controls the operation of the A/C and heating system based on inputs from the temperature control knob, the mode switches, the blower control dial, the ambient temperature sensor, the intake sensor, and inputs received from the ECM across the CAN. Diagnosis of the A/C switch assembly can be performed using the CONSULT. There is no self-diagnostic feature available.
Air mix door motor 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 LH receives position commands from the A/C auto amp.
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.
Blower motor relay The blower motor relay controls the flow of current to fuse 20, 21 and 22 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. The intake door motor receives position commands from the A/C auto amp.
Intake sensor The intake sensor measures the temperature of the front evaporator fins. The sensor uses a thermistor which is sensitive to the change in temperature. The electrical resistance of the thermistor decreases as temperature increases.
IPDM E/R Refer to PCS-7, "RELAY CONTROL SYSTEM : System Description" (with Intelligent Key system) or PCS-35, "RELAY CONTROL SYSTEM : System Description" (without Intelligent Key system).
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 mode door motor receives position commands from the A/C auto amp.

Refrigerant pressure sensor Refer to EC-29, "Refrigerant Pressure Sensor".

SYSTEM

System Diagram

System Description


System Description

Controlled by front air control:

Controlled by BCM:

Control by ECM

Control by IPDM E/R

Air Flow Control

DESCRIPTION

FAN SPEED CONTROL AT DOOR MOTOR OPERATION

When mode door motor is activated while air flow is more than the specified value, front air control temporarily reduces fan speed so that mode door moves smoothly.

Air Inlet Control

The intake door position is automatically controlled in MAX A/C and DEF modes. The intake door is controlled by customer input in the other modes.

Air Outlet Control

Air outlet control is controlled by customer input. When the A/C is turned off by turning the blower control dial fully counterclockwise, the front air control retains the current selections and returns to these selections the next time the blower control dial is turned to any fan position.

NOTE:

If ambient temperature is excessively low, D/F is selected to prevent windshield fogging when air outlet is set to FOOT.

Compressor Control

DESCRIPTION

In order for the IPDM E/R to complete a compressor ON request, the following conditions must be met:

  1. The BCM detects a Fan ON signal from the front air control. The front air control grounds the fan ON signal monitored by the BCM when the blower speed dial is in any of the fan speed positions.
  2. The BCM detects an A/C ON signal from the front air control. The front air control grounds the A/C ON signal monitored by the BCM when:

NOTE:

If the compressor was engaged by pressing the D/F or DEF mode buttons, and the time spent in either mode exceeds 1 minute, then the compressor stays requested, even when modes other than D/F or DEF are selected, until either:

  1. The ignition switch is turned OFF.
  2. The blower speed dial is turned completely counterclockwise to the OFF position
  3. The A/C switch is manually turned OFF.

In other words, the compressor ON request cannot be turned off in D/F or DEF modes.

REFRIGERANT PRESSURE PROTECTION

The refrigerant system is protected against excessively high- or low-pressures by the refrigerant pressure sensor, located on the liquid tank on the condenser. The refrigerant pressure sensor detects the pressure inside the refrigerant line and sends a voltage signal to the ECM. If the system pressure rises above or falls below the following values, the ECM requests the IPDM E/R to de-energize the A/C relay and disengage the compressor.

PRESSURE RELIEF VALVE

The refrigerant system is also protected by a pressure relief valve, located in the rear head of the compressor.

When the pressure of refrigerant in the system increases to an abnormal level [more than 2,990 kPa (30.5 kg/ cm2, 433.6 psi)], the release port on the pressure relief valve automatically opens and releases refrigerant into the atmosphere.

COMPRESSOR OIL CIRCULATION CONTROL

When the engine starts while the engine coolant temperature is 56В°C (133В°F) or less, ECM activates the compressor for approximately 6 seconds and circulates the compressor lubricant once.

LOW TEMPERATURE PROTECTION CONTROL

OPERATING RATE CONTROL

When the set temperature is other than fully cold or the air outlet is “VENT”, “B/L” or “FOOT”, the front air control controls the compressor activation depending on ambient temperature.

Door Control

AIR MIX DOOR MOTOR

DESCRIPTION

DRIVE METHOD

Mode door motor


Mode door motor

DESCRIPTION

DRIVE METHOD

INTAKE DOOR MOTOR


INTAKE DOOR MOTOR

Switches and their control function


  1. Intake door
  2. Blower motor
  3. Air conditioner filter
  4. Evaporator
  5. Upper air mix door (driver side/passenger side)
  6. Lower air mix door (driver side/passenger side)
  7. Heater core
  8. Foot door
  9. Side ventilator door
  10. Sub defroster door
  11. Center ventilator and defroster door

Recirculation airFresh air intake


Discharge airRecirculation air


DefrosterDischarge air


Center ventilator Defroster


Side ventilatorCenter ventilator


Rear ventilatorSide ventilator


Front footRear ventilator


Rear footFront foot


Rear foot


Air distribution


Air distribution

Temperature Control


Temperature Control

OPERATION

Switch Name and Function

A/C switch assembly


  1. A/C switch
  2. Blower control dial (with OFF switch)
  3. DEF switch
  4. Rear DEF switch
  5. REC switch
  6. Temperature control dial
  7. MAX A/C switch
  8. D/F switch
  9. FOOT switch
  10. B/L switch
  11. VENT switch

Switch Operation


DIAGNOSIS SYSTEM (BCM) (WITH INTELLIGENT


DIAGNOSIS SYSTEM (BCM) (WITH INTELLIGENT KEY SYSTEM)

COMMON ITEM

COMMON ITEM : CONSULT Function (BCM - COMMON ITEM)

Application item

CONSULT performs the following functions via CAN communication with BCM.

System application


System application

BCM can perform the following functions.

AIR CONDITIONER


AIR CONDITIONER

AIR CONDITIONER : CONSULT Function (BCM - AIR CONDITIONER)

Data monitor

DIAGNOSIS SYSTEM (BCM) (WITHOUT INTELLIGENT KEY SYSTEM)


DIAGNOSIS SYSTEM (BCM) (WITHOUT INTELLIGENT KEY SYSTEM)

COMMON ITEM

COMMON ITEM : CONSULT Function (BCM - COMMON ITEM)

Application item

CONSULT performs the following functions via CAN communication with BCM.

System application


System application

BCM can perform the following functions.

Air conditioner


Air conditioner

AIR CONDITIONER : CONSULT Function (BCM - AIR CONDITIONER)

DIAGNOSIS SYSTEM (IPDM E/R) (WITH INTELLIGENT


DIAGNOSIS SYSTEM (IPDM E/R) (WITH INTELLIGENT KEY SYSTEM)

Diagnosis Description

Auto active test

Description

In auto active test, the IPDM E/R sends a drive signal to the following systems to check their operation.

Operation Procedure

NOTE:

Never perform auto active test in the following conditions.

  1. Close the hood and lift the wiper arms from the windshield. (Prevent windshield damage due to wiper operation)

NOTE:

When auto active test is performed with hood opened, sprinkle water on windshield beforehand.

  1. Turn the ignition switch OFF.
  2. Turn the ignition switch ON, and within 20 seconds, press the driver door switch 10 times. Then turn the ignition switch OFF.
  3. Turn the ignition switch ON within 10 seconds. After that the horn sounds once and the auto active test starts.
  4. After a series of the following operations is repeated 3 times, auto active test is completed.

NOTE:

Inspection in Auto Active Test

When auto active test is actuated, the following operation sequence is repeated 3 times.

Concept of Auto Active Test


Concept of Auto Active Test


Diagnosis Chart in Auto Active Test

Consult Function (IPDM E/R)


Consult Function (IPDM E/R)

Application item

Consult performs the following functions via can communication with ipdm e/r.


Ecu identification


Ecu identification

The IPDM E/R part number is displayed.

SELF DIAGNOSTIC RESULT

Refer to PCS-20, "DTC Index".

DATA MONITOR

ACTIVE TEST


ACTIVE TEST


CAN DIAG SUPPORT MNTR


CAN DIAG SUPPORT MNTR

Refer to LAN-13, "CAN Diagnostic Support Monitor".

DIAGNOSIS SYSTEM (IPDM E/R) (WITHOUT INTELLIGENT KEY SYSTEM)

Diagnosis Description

AUTO ACTIVE TEST

Description

In auto active test, the IPDM E/R sends a drive signal to the following systems to check their operation.

Operation Procedure

NOTE:

Never perform auto active test in the following conditions.

  1. Close the hood and lift the wiper arms from the windshield. (Prevent windshield damage due to wiper operation)

NOTE:

When auto active test is performed with hood opened, sprinkle water on windshield beforehand.

  1. Turn the ignition switch OFF.
  2. Turn the ignition switch ON, and within 20 seconds, press the driver door switch 10 times. Then turn the ignition switch OFF.
  3. Turn the ignition switch ON within 10 seconds. After that the horn sounds once and the auto active test starts.
  4. After a series of the following operations is repeated 3 times, auto active test is completed.

NOTE:

Inspection in Auto Active Test

When auto active test is actuated, the following operation sequence is repeated 3 times.

Concept of Auto Active Test


Concept of Auto Active Test


Diagnosis Chart in Auto Active Test

Consult Function (IPDM E/R)


Consult Function (IPDM E/R)

APPLICATION ITEM

CONSULT performs the following functions via CAN communication with IPDM E/R.


Ecu identification


Ecu identification

The IPDM E/R part number is displayed.

SELF DIAGNOSTIC RESULT

Refer to PCS-48, "DTC Index".

DATA MONITOR

ACTIVE TEST


ACTIVE TEST


CAN DIAG SUPPORT MNTR


CAN DIAG SUPPORT MNTR

Refer to LAN-13, "CAN Diagnostic Support Monitor".

Preparation
Special Service Tool The actual shape of the tools may differ from those illustrated here. Commercial Service Tool ...

ECU diagnosis information
A/C AUTO AMP Reference Value TERMINAL LAYOUT PHYSICAL VALUES *:With manual A/C ECM, IPDM E/R, BCM List of ECU Reference ...

Other materials:

Tightening Torque Table (New Standard Included)
CAUTION: The special parts are excluded. The bolts/nuts in these tables have a strength (discrimination) number/symbol assigned to the head or the like. As to the relation between the strength grade in these tables and the strength (discrimination) number/symbol, refer to “DISCR ...

Windows
Power windows WARNING Make sure that all passengers have their hands, etc. inside the vehicle while it is in motion and before closing the windows. Use the window lock switch to prevent unexpected use of the power windows. Do not leave children unattended inside ...

Diagnosis system (bcm) (with intelligent key system)
Common item COMMON ITEM : CONSULT Function (BCM - COMMON ITEM) APPLICATION ITEM CONSULT performs the following functions via CAN communication with BCM. Direct Diagnostic Mode Description ECU identification The BCM part number is displayed. Self Diagnostic Result ...

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