Nissan Pathfinder (2008 year). Manual - part 441

HAC-72

< COMPONENT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

WATER VALVE CIRCUIT

WATER VALVE CIRCUIT

Water Valve Description (VK56DE)

INFOID:0000000001366730

COMPONENT DESCRIPTION

Water Valve

The water valve (1) cuts the flow of engine coolant to the front and
rear heater cores to allow for maximum cooling during A/C opera-
tion. It is controlled by the A/C auto amp.

Water Valve Diagnosis Procedure (VK56DE)

INFOID:0000000001366731

DIAGNOSTIC PROCEDURE FOR WATER VALVE

1.

CHECK WATER VALVE POWER AND GROUND CIRCUITS

1.

Disconnect water valve connector F68.

2.

Turn ignition switch ON.

3.

Rotate temperature control dial (driver) to 32

°

C (90

°

F).

4.

Check voltage between water valve harness connector F68 ter-
minal 1 and terminal 2 while rotating temperature control dial
(driver) to 18

°

C (60

°

F). 

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> GO TO 2.

2.

CHECK WATER VALVE CONTROL OUTPUT CIRCUIT 

1.

Turn ignition switch OFF.

2.

Disconnect A/C auto amp. connector M50.

3.

Check continuity between water valve harness connector F68
(A) terminal 2 and A/C auto amp. harness connector M50 (B)
terminal 46.

4.

Check continuity between water valve harness connector F68
terminal 2 and ground.

Is the inspection result normal?

YES

>> Replace A/C auto amp. Refer to 

VTL-8, "Removal and Installation"

.

NO

>> Repair harness or connector.

3.

CHECK WATER VALVE POWER AND GROUND CIRCUITS

WJIA1791E

Connector

Terminals

Condition 

Voltage 

(Approx.)

(+) (-)

Water valve: F68

2 

1

Rotate temperature 

control dial

Battery 
voltage

WJIA1794E

2 - 46

: Continuity should exist.

2 - Ground

: Continuity should not exist.

AWIIA0203ZZ

WATER VALVE CIRCUIT

HAC-73

< COMPONENT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

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1.

Rotate temperature control dial (driver) to 18

°

C (60

°

F).

2.

Check voltage between water valve harness connector F68 ter-
minal 1 and terminal 2 while rotating temperature control dial
(driver) to 32

°

C (90

°

F). 

Is the inspection result normal?

YES

>>  Replace the water valve. 

NO

>> GO TO 4.

4.

CHECK WATER VALVE CONTROL OUTPUT CIRCUIT 

1.

Turn ignition switch OFF.

2.

Disconnect A/C auto amp. connector M50.

3.

Check continuity between water valve harness connector F68
(A) terminal 1 and A/C auto amp. harness connector M50 (B)
terminal 45.

4.

Check continuity between water valve harness connector F68
(A) terminal 1 and ground.

Is the inspection result normal?

YES

>> Replace A/C auto amp. Refer to 

VTL-8, "Removal and Installation"

.

NO

>> Repair harness or connector.

Connector

Terminals

Condition 

Voltage 

(Approx.)

(+) (-)

Water valve: F68

1 

2

Rotate temperature 

control dial

Battery 
voltage

WJIA1792E

1 - 45

: Continuity should exist.

1 - Ground

: Continuity should not exist.

AWIIA0204ZZ

HAC-74

< COMPONENT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

HEATER PUMP

HEATER PUMP

System Description (VQ40DE)

INFOID:0000000001404888

SYSTEM DESCRIPTION

Component Parts

Heater pump control system components are:
• A/C auto amp.
• Heater pump relay
• Heater pump
• Intake sensor

System Operation

The heater pump improves heater performance specifically at idle conditions. It is designed to operate in
either of the following 2 situations:
1.

Front blower motor set to maximum speed and temperature control dial (driver or passenger) set to full hot
32

°

 C (90

°

 F) or

2.

Engine coolant temperature (signal via CAN communication) minus heater core outlet temperature (intake
sensor input to A/C auto amp.) is greater than 20

°

 C (68

°

 F). If the difference is less than 16

°

 C (61

°

 F),

the heater pump will not operate unless the conditions in item No. 1 above are met.

Diagnosis Procedure (VQ40DE)

INFOID:0000000001404889

DIAGNOSTIC PROCEDURE FOR HEATER PUMP CIRCUIT

1.

CHECK POWER SUPPLY TO HEATER PUMP

1.

Disconnect heater pump connector.

2.

Turn ignition switch ON.

3.

Set front blower motor to maximum speed.

4.

Turn temperature control dial (passenger or driver) to full hot 32

°

 C (90

°

 F).

5.

Check voltage between heater pump harness connector E141
terminal 1 and ground.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> GO TO 3.

WJIA1780E

1 - Ground

: Battery voltage

WJIA1984E

HEATER PUMP

HAC-75

< COMPONENT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

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2.

CHECK HEATER PUMP GROUND

1.

Turn ignition switch OFF.

2.

Check continuity between heater pump harness connector E141
terminal 2 and ground.

Is the inspection result normal?

YES

>> Replace heater pump. Refer to 

HA-58, "Removal and

Installation"

.

NO

>> Repair harness or connector.

3.

CHECK HEATER PUMP RELAY

1.

Turn ignition switch OFF.

2.

Check heater pump relay. Refer to 

HAC-76, "Component Inspection (VQ40DE)"

.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Replace heater pump relay.

4.

CHECK RELAY POWER SUPPLY

1.

Turn ignition switch ON.

2.

Check voltage between heater pump relay harness connector
E144 terminals 2, 5 and ground.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Repair harness or connector.

5.

CHECK HEATER PUMP MOTOR POWER CIRCUIT

1.

Turn ignition switch OFF.

2.

Check continuity between heater pump relay harness connector
(A) E144 terminal 3 and heater pump harness connector (B)
E141 terminal 1.

3.

Check continuity between heater pump relay harness connector
(A) E144 terminal 3 and ground.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Repair harness or connector.

6.

CHECK CIRCUIT BETWEEN HEATER PUMP RELAY AND A/C AUTO AMP.

2 - Ground

: Continuity should exist.

WJIA1985E

2 - Ground

: Battery voltage

5 - Ground

: Battery voltage

WJIA1986E

3 - 1

: Continuity should exist.

3 - Ground

: Continuity should not exist.

WJIA1987E

HAC-76

< COMPONENT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

HEATER PUMP

1.

Disconnect A/C auto amp. connector.

2.

Check continuity between A/C auto amp. harness connector (A)
M50 terminal 50 and heater pump relay harness connector (B)
E144 terminal 1.

3.

Check continuity between heater pump relay harness connector
(B) E144 terminal 1 and ground.

Is the inspection result normal?

YES

>> Replace A/C auto amp. Refer to 

VTL-8, "Removal and Installation"

.

NO

>> Repair harness or connector.

Component Inspection (VQ40DE)

INFOID:0000000001404928

COMPONENT INSPECTION

Heater Pump Relay

Check continuity between terminals 3 and 5.

If NG, replace relay.

1 - 50

: Continuity should exist.

1 - Ground

: Continuity should not exist.

AWIIA0263ZZ

Conditions

Continuity

12V direct current supply between terminals 1 and 2

Yes

No current supply

No

LHA160

AMBIENT SENSOR

HAC-77

< COMPONENT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

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AMBIENT SENSOR

Component Description

INFOID:0000000001366732

COMPONENT DESCRIPTION

Ambient Sensor

Ambient sensor (1) is attached to the radiator core support (left side). It detects ambient temperature and con-
verts it into a value which is then input into the A/C auto amp.
•

⇐

: Front

AMBIENT TEMPERATURE INPUT PROCESS

The A/C auto amp. includes a processing circuit for the ambient sensor input. However, when the temperature
detected by the ambient sensor increases quickly, the processing circuit retards the A/C auto amp. function. It
only allows the A/C auto amp. to recognize an ambient temperature increase of 0.33

°

C (0.6

°

F) per 100 sec-

onds.
This prevents constant adjustments due to momentary conditions, such as stopping after high speed driving.
Although the actual ambient temperature has not changed, the temperature detected by the ambient sensor
will increase. This is because the heat from the engine compartment can radiate to the front grille area, loca-
tion of the ambient sensor.

Ambient Sensor Diagnosis Procedure

INFOID:0000000001366733

DIAGNOSTIC PROCEDURE FOR AMBIENT SENSOR

SYMPTOM: Ambient sensor circuit is open or shorted. (40 or 41 is
indicated on A/C auto amp. as a result of conducting the A/C auto
amp. self-diagnosis)

1.

CHECK VOLTAGE BETWEEN AMBIENT SENSOR AND GROUND

1.

Disconnect ambient sensor connector.

2.

Turn ignition switch ON.

3.

Check voltage between ambient sensor harness connector E1
terminal 1 and ground.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> GO TO 5.

AWIIA0262ZZ

AWIIA0160GB

1 - Ground

: Approx. 5V

AWIIA0161ZZ

HAC-78

< COMPONENT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

AMBIENT SENSOR

2.

CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT SENSOR AND A/C AUTO AMP. 

1.

Turn ignition switch OFF.

2.

Disconnect A/C auto amp. connector.

3.

Check continuity between ambient sensor harness connector
E1 (B) terminal 1 and A/C auto amp. harness connector M49 (A)
terminal 25.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair harness or connector.

3.

CHECK AMBIENT SENSOR

Check the Ambient Sensor Circuit. Refer to 

HAC-78, "Ambient Sensor Component Inspection"

.

Is the inspection result normal?

YES

>> 1.

Replace A/C auto amp. Refer to 

VTL-8, "Removal and Installation"

.

2.

GO TO 

HAC-23, "A/C Auto Amp. Self-Diagnosis"

 and perform self-diagnosis.

NO

>> 1.

Replace ambient sensor.

2.

GO TO 

HAC-23, "A/C Auto Amp. Self-Diagnosis"

 and perform self-diagnosis.

4.

CHECK CIRCUIT CONTINUITY BETWEEN AMBIENT SENSOR AND A/C AUTO AMP.

1.

Turn ignition switch OFF.

2.

Disconnect A/C auto amp. connector.

3.

Check continuity between ambient sensor harness connector
E1 (B) terminal 2 and A/C auto amp. harness connector M49 (A)
terminal 26.

4.

Check continuity between ambient sensor harness connector
E1 (B) terminal 2 and ground.

Is the inspection result normal?

YES

>> 1.

Replace A/C auto amp. Refer to 

VTL-8, "Removal and Installation"

2.

GO TO 

HAC-23, "A/C Auto Amp. Self-Diagnosis"

 and perform self-diagnosis.

NO

>> Repair harness or connector.

Ambient Sensor Component Inspection

INFOID:0000000001366734

COMPONENT INSPECTION

Ambient Sensor

1 - 25

: Continuity should exist.

AWIIA0162ZZ

2 - 26

: Continuity should exist.

2 - Ground

: Continuity should not exist.

AWIIA0163ZZ

AMBIENT SENSOR

HAC-79

< COMPONENT DIAGNOSIS >

[AUTOMATIC AIR CONDITIONER]

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After disconnecting ambient sensor (1) connector E1, measure
resistance between terminals 1 and 2 at sensor component side,
using the table below.
•

⇐

: Front

NOTE:
The ambient sensor is located behind the front grille, below the hood
latch. The ambient sensor (1) provides input for the automatic A/C
system.

If NG, replace ambient sensor. Refer to XXXX

Temperature 

°

C (

°

F)

Resistance k

Ω

−

15 (5)

12.73

−

10 (14)

9.92

−

5 (23)

7.80

0 (32)

6.19

5 (41)

4.95

10 (50)

3.99

15 (59)

3.24

20 (68)

2.65

25 (77)

2.19

30 (86)

1.81

35 (95)

1.51

40 (104)

1.27

45 (113)

1.07

WJIA1981E