Nissan Sentra B18 (2020-2025) Service Manual: Diagnosis System (a/c Auto Amp.)

Nissan Sentra B18 (2020-2025) Service Manual / Ventilation, Heater & Air Conditioner / Heater & Air Conditioning Control System :: Automatic Air Conditioner / System Description / Diagnosis System (a/c Auto Amp.)

Description

Description

Air conditioning system performs self-diagnosis, operation check, function diagnosis, and various settings using diagnosis function of each control unit.

ECU	Diagnostic item (CONSULT)
A/C auto amp.	HVAC	Self Diagnostic Result
		Data Monitor
		Active Test
		Work support
BCM	BCM-AIR CONDITIONER	Self Diagnostic Result
BCM	BCM-AIR CONDITIONER	Data Monitor
ECM	ENGINE	Self Diagnostic Result
ECM	ENGINE	Data Monitor
IPDM E/R	IPDM E/R	Self Diagnostic Result
	IPDM E/R	Data Monitor
	Auto active test

Consult Function (hvac)

CONSULT Function (HVAC)

CONSULT performs the following functions via CAN communication with A/C auto amp.:

Diagnostic mode	CGW Status			Description
Diagnostic mode	Restricted Mode	Diag Test Mode	Open Mode	Description
Self Diagnostic Result	Display	Display	Display	Display non-network DTC which A/C auto amp. memorizes.
CGW Information	Display	Display	Display	Display the current CGW mode. Enables CGW to switch mode.
Data Monitor	Display	Display	Display	Displays the input/output signal of A/C auto amp.
Active Test	Non display	Display	Display	The signals used to activate each device are forcibly supplied from A/C auto amp.
Work support	Non display	Non display	Display	Changes the setting for each setting function.
ECU Identification	Display	Display	Display	Displays the part number of A/C auto amp.
Network-DTC*	Display	Display	Display	Display network DTC which A/C auto amp. memorizes when performing “Diagnosis (All System)”.

*: Displays when performing “Diagnosis (All System)”.

Note:

Diagnosis should be performed with engine running. Door motor operation speeds become slower and NO results may be returned even for normal operation if battery voltage drops below 12 V during self-diagnosis.

SELF DIAGNOSTIC RESULT

Diagnosis result that is judged by A/C auto amp. can be checked. Refer to DTC Index.

CGW INFORMATION

Display the diagnosis mode which a user can perform in Diag Test mode/Open Mode by switching the CGW status from Restricted mode to Diag Test Mode/Open Mode.

DATA MONITOR

Input/output signal of A/C auto amp. can be checked.

Note:

The following table includes information (items) inapplicable to this Nissan Sentra vehicle: For information (items) applicable to this vehicle, refer to CONSULT display items.

Display item list
Monitor item [Unit]		Description
AMB TEMP SEN	[°C]	Ambient temperature signal value received from combination meter via CAN communication.
IN-VEH TEMP	[°C]	In-Nissan Sentra vehicle temperature value converted from in-vehicle sensor signal received from in-vehicle sensor.
INT TEMP SEN	[°C]	Evaporator fin temperature value converted from intake sensor signal received from intake sensor.
SUNLOAD SEN	[W/m^2]	Sunload value converted from sunload sensor signal received from sunload sensor.
AMB SEN CAL	[°C]	Ambient temperature value calculated by A/C auto amp.
IN-VEH CAL	[°C]	In-Nissan Sentra vehicle temperature value calculated by A/C auto amp.
INT TEMP CAL	[°C]	Evaporator fin temperature value calculated by A/C auto amp.
SUNL SEN CAL	[W/m^2]	Sunload value calculated by A/C auto amp.
XM		Target discharge air temperature (Driver side) judged by A/C auto amp. depending on the temperature setting and the value from each sensor.
FAN REQ SIG	[On/Off]	Displays blower fan ON signal ON/OFF status transmitted to ECM.
FAN DUTY	[%]	Duty ratio of blower motor judged by A/C auto amp.
COMP REQ SIG	[On/Off]	Displays A/C ON signal ON/OFF status transmitted to ECM.
A/C comp clutch status	[On/Off]	A/C compressor status judged from the A/C compressor feedback signal received from IPDM E/R via CAN communication.
Cooling fan request	[%]	Displays cooling fan speed request signal transmitted to ECM via CAN communication.
Rear window defogger request	[On/Off]	Display the rear window defogger request signal ON/OFF status transmitted to BCM via CAN communication.
Eco mode request	[Not REQ/ Request]	Display the drive mode signal received from BCM via CAN communication.
Illumination control duty	[%]	Display the illumination control output duty signal received from combination meter via CAN communication.
Refrigerant PRESS SEN value	[Bar]	Display the refrigerant pressure sensor signal received from ECM via CAN communication.
Heated steering wheel request		Note: This item displayed, but cannot be monitored.
Nissan Sentra Vehicle speed	[km/h]	Nissan Sentra Vehicle speed signal value received from ABS actuator and electric unit (control unit) via CAN communication.
ODO/TRIP METER	[km]	Odometer signal value received from ABS actuator and electric unit (control unit) via CAN communication.
Engine RPM	[rpm]	Engine speed signal value received from ECM via CAN communication.
ENG COOL TEMP	[°C]	Engine coolant temperature signal value received from ECM via CAN communication.

ACTIVE TEST

The signals used to activate each device forcibly supplied from A/C auto amp. operation check of air conditioning system can be performed.

Test item	Description
HVAC TEST	The operation check of air conditioning system can be performed by selecting the mode. Refer to the following table for the conditions of each mode.

Check each output device

	Test item
	MODE 1	MODE 2	MODE 3	MODE 4	MODE 5	MODE 6	MODE 7
Mode door motor position	VENT	VENT	B/L	B/L	FOOT	D/F	DEF
Intake door motor position	REC	REC	20% FRE	20% FRE	FRE	FRE	FRE
Air mix door motor (driver side) position	FULL COLD	FULL HOT	FULL COLD	FULL HOT	FULL HOT	FULL HOT	FULL HOT
Air mix door motor (passenger side) position	FULL COLD	FULL HOT	FULL COLD	FULL HOT	FULL HOT	FULL HOT	FULL HOT
Blower motor control signal (duty ratio)	35%	35%	61%	61%	89%	89%	35%
Magnet clutch (A/C compressor request signal)	ON	ON	ON	ON	OFF	OFF	ON
ECV duty ratio	80%	80%	40%	40%	0%	0%	90%

Note:

Perform the inspection of each output device after starting the engine because the A/C compressor is operated.

WORK SUPPORT

Setting change of each setting functions can be performed.

Work support items	Description	Display	Setting
TEMP SET CORRECT	If the temperature felt by the customer is different from the air flow temperature controlled by the temperature setting, the A/C auto amp. control temperature can be adjusted to compensate for the temperature setting.	3.0°C	Note: When −3.0°C is corrected on the temperature setting set as 25.0°C the temperature controlled by A/C auto amp. is 25.0°C −3.0°C = 22.0°C and the temperature becomes lower than the temperature setting.
		2.5°C
		2.0°C
		1.5°C
		1.0°C
		0.5°C
		0.0°C^*
		−0.5°C
		−1.0°C
		−1.5°C
		−2.0°C
		−2.5°C
		−3.0°C
REC MEMORY SET	If the ignition switch is placed to the OFF position while the intake switch is set to ON (recirculation), “Perform the memory” or “Do not perform the memory” of intake switch ON (recirculation) condition can be selected.	USE^*	Perform the memory of manual REC If “Perform the memory” was set, the intake switch will be ON (recirculation) when placing the ignition switch to the ON position again.
REC MEMORY SET		NOT USE	Do not perform the memory of manual REC (auto control) If “Do not perform the memory” was set, the air inlets will be controlled automatically when placing the ignition switch to the ON position again.
FRE MEMORY SET	If the ignition switch is placed to the OFF position while the intake switch is set to OFF (fresh air intake), “Perform the memory” or “Do not perform the memory” of intake switch OFF (fresh air intake) condition can be selected.	USE	Perform the memory of manual FRE If “Perform the memory” was set, the intake switch will be OFF (fresh air intake) when placing the ignition switch to the ON position again.
FRE MEMORY SET		NOT USE^*	Do not perform the memory of manual FRE (auto control) If “Do not perform the memory” was set, the air inlets will be controlled automatically when placing the ignition switch to the ON position again.
BLOW SET	In FOOT mode, the air blowing to DEF can change ON/OFF.	O/A C/M^*	Auto control: Defroster door position (open) Manual control: Defroster door position (close)
		O/A O/M	Auto control: Defroster door position (open) Manual control: Defroster door position (open)
		C/A O/M	Auto control: Defroster door position (close) Manual control: Defroster door position (open)
		C/A C/M	Auto control: Defroster door position (close) Manual control: Defroster door position (close)
TARGET EVAPORATOR TEMP UPPER LIMIT SETTING	Setting of upper limit value of target evaporator temperature can be changed. Control characteristic of A/C compressor control (freezing protection control and refrigerant discharge amount control) changes according to change of the setting, and then operation ratio of A/C compressor and refrigerant discharge amount are changed. According to change of the setting, control characteristic focusing on the fuel consumption can be adjusted to control characteristic focusing on the cooling capacity.	DEFAULT^*	Target evaporator temperature upper limit value: 50°F (10°C)
		3°C	Target evaporator temperature upper limit value: 37°F (3°C)
		5°C	Target evaporator temperature upper limit value: 41°F (5°C)
		7°C	Target evaporator temperature upper limit value: 45°F (7°C)

*: Initial status

Note:

When the battery cable is disconnected from the negative terminal or when the battery voltage is 10 V or less, the setting for the work support item is set to the value stored 1 minute after most recent ignition switch OFF status.

ECU IDENTIFICATION

Part number of A/C auto amp. can be checked.

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