Nissan Leaf. Manual - part 785

B27C2, B27C3 PTC HEATER OUTLET AIR TEMPERATURE SENSOR

HAC-143

< DTC/CIRCUIT DIAGNOSIS >

[AUTO A/C (WITH HEAT PUMP)]

C

D

E

F

G

H

J

K

L

M

A

B

HAC

N

O

P

YES

>> GO TO 7.

NO

>> GO TO 2.

2.

CHECK PTC HEATER OUTLET AIR TEMPERATURE SENSOR POWER SUPPLY

1. Turn power switch OFF.

2. Disconnect PTC heater outlet air and A/C unit case temperature sensor assembly connector. 

3. Turn power switch ON.

4. Check voltage between PTC heater outlet air and A/C unit case temperature sensor assembly harness

connector and ground. 

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> GO TO 5.

3.

CHECK PTC HEATER OUTLET AIR TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN

1. Turn power switch OFF.

2. Disconnect A/C auto amp. connector. 

3. Check continuity between PTC heater outlet air and A/C unit case temperature sensor assembly harness

connector and A/C auto amp harness connector. 

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair harness or connector.

4.

CHECK PTC HEATER OUTLET AIR TEMPERATURE SENSOR

Check PTC heater outlet air temperature sensor. Refer to 

HAC-144, "Component Inspection"

.

Is the inspection result normal?

YES

>> Inspection End.

NO

>> Replace PTC heater outlet air and A/C unit case temperature sensor assembly. Refer to 

HAC-

198, "Removal and Installation"

.

5.

CHECK PTC HEATER OUTLET AIR TEMPERATURE SENSOR POWER SUPPLY CIRCUIT FOR OPEN

1. Turn power switch OFF.

2. Disconnect A/C auto amp. connector. 

3. Check continuity between PTC heater outlet air and A/C unit case temperature sensor assembly harness

connector and A/C auto amp. harness connector. 

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Repair harness or connector.

6.

CHECK PTC HEATER OUTLET AIR TEMPERATURE SENSOR POWER SUPPLY CIRCUIT FOR SHORT

+

−

Voltage

(Approx.)

PTC heater outlet air and A/C unit case temperature sensor as-

sembly

Connector

Terminal

M138

2

Ground

5 V

PTC heater outlet air and A/C unit case temperature 

sensor assembly

A/C auto amp.

Continuity

Connector

Terminal

Connector

Terminal

M138

1

M55

30

Yes

PTC heater outlet air and A/C unit case temperature 

sensor assembly

A/C auto amp.

Continuity

Connector

Terminal

Connector

Terminal

M138

2

M55

17

Yes

HAC-144

< DTC/CIRCUIT DIAGNOSIS >

[AUTO A/C (WITH HEAT PUMP)]

B27C2, B27C3 PTC HEATER OUTLET AIR TEMPERATURE SENSOR

Check continuity between PTC heater outlet air and A/C unit case temperature sensor assembly harness con-

nector and ground. 

Is the inspection result normal?

YES

>> Replace A/C auto amp. Refer to 

HAC-187, "Removal and Installation"

.

NO

>> Repair harness or connector.

7.

CHECK INTERMITTENT INCIDENT

Check intermittent incident. Refer to 

GI-53, "Intermittent Incident"

.

Is the inspection result normal?

YES

>> Replace A/C auto amp. Refer to 

HAC-187, "Removal and Installation"

.

NO

>> Repair or replace malfunctioning components.

Component Inspection

INFOID:0000000010121852

1.

CHECK PTC HEATER OUTLET AIR TEMPERATURE SENSOR

1. Remove PTC heater outlet air and A/C unit case temperature sensor assembly. Refer to 

HAC-198,

"Removal and Installation"

. 

2. Check resistance between PTC heater outlet air and A/C unit case temperature sensor assembly termi-

nals. Refer to applicable table for the normal value. 

Is the inspection result normal?

YES

>> Inspection End.

NO

>> Replace PTC heater outlet air and A/C unit case temperature sensor assembly. Refer to 

HAC-

198, "Removal and Installation"

.

PTC heater outlet air and A/C unit case temperature sensor as-

sembly

—

Continuity

Connector

Terminal

M138

2

Ground

No

Terminal

Condition

Resistance: k

Ω

Temperature: 

°C (°F) 

1

2

0 (32) 

6.00

10 (50)

3.87

20 (68)

2.57

30 (86)

1.76

40 (104)

1.23

60 (140)

0.64

80 (176)

0.36

100 (212)

0.22

B27C4, B27C5 A/C UNIT CASE TEMPERATURE SENSOR

HAC-145

< DTC/CIRCUIT DIAGNOSIS >

[AUTO A/C (WITH HEAT PUMP)]

C

D

E

F

G

H

J

K

L

M

A

B

HAC

N

O

P

B27C4, B27C5 A/C UNIT CASE TEMPERATURE SENSOR

DTC Logic

INFOID:0000000010121853

DTC DETECTION LOGIC 

NOTE:

• If DTC is displayed along with DTC U1000, first perform the trouble diagnosis for DTC U1000. Refer to 

HAC-

87, "DTC Logic"

.

• If DTC is displayed along with DTC U1010, first perform the trouble diagnosis for DTC U1010. 

HAC-88,

"DTC Logic"

.

DTC CONFIRMATION PROCEDURE

1.

PERFORM DTC CONFIRMATION PROCEDURE

With CONSULT

1. Turn power switch OFF.

2. Set the vehicle to READY.

3. Operate the automatic air conditioning system.

4. Set the temperature to full hot and wait at least 2 seconds.

5. Select “Self Diagnostic Result” of “HVAC” using CONSULT.

6. Check DTC.
Is DTC detected?

YES

>> Refer to 

HAC-145, "Diagnosis Procedure"

.

NO

>> Inspection End.

Diagnosis Procedure

INFOID:0000000010121854

Regarding Wiring Diagram information, refer to 

HAC-61, "Wiring Diagram"

.

1.

CHECK A/C UNIT CASE TEMPERATURE SENSOR VOLTAGE SIGNAL

1. Turn power switch ON.

2. Operate the automatic air conditioning system.

3. Check voltage between A/C auto amp. harness connector terminals.

Is the inspection result normal?

DTC

Items

(CONSULT screen terms)

DTC detection condition

Possible cause

B27C4

A/C UNIT CASE TEMP 
SENS

The A/C unit case temperature sensor recogni-
tion temperature is too low [less than 

−42°C (−

44

°F)].

• A/C unit case temperature sensor
• A/C auto amp.
• Harness or connectors

(The sensor circuit is open or short-
ed.)

B27C5

The A/C unit case temperature sensor recogni-
tion temperature is too high [more than 200

°C 

(392

°F)].

A/C auto amp.

Test condition

Voltage signal

connector

+

−

Terminal

M55

37

10

• Power switch ON
• When air conditioner is op-

erating

JSIIA1778ZZ

HAC-146

< DTC/CIRCUIT DIAGNOSIS >

[AUTO A/C (WITH HEAT PUMP)]

B27C4, B27C5 A/C UNIT CASE TEMPERATURE SENSOR

YES

>> GO TO 7.

NO

>> GO TO 2.

2.

CHECK A/C UNIT CASE TEMPERATURE SENSOR POWER SUPPLY

1. Turn power switch OFF.

2. Disconnect PTC heater outlet air and A/C unit case temperature sensor assembly connector. 

3. Turn power switch ON.

4. Check voltage between PTC heater outlet air and A/C unit case temperature sensor assembly harness

connector and ground. 

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> GO TO 5.

3.

CHECK A/C UNIT CASE TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN

1. Turn power switch OFF.

2. Disconnect A/C auto amp. connector. 

3. Check continuity between PTC heater outlet air and A/C unit case temperature sensor assembly harness

connector and A/C auto amp harness connector. 

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair harness or connector.

4.

CHECK A/C UNIT CASE TEMPERATURE SENSOR

Check A/C unit case temperature sensor. Refer to 

HAC-153, "Component Inspection"

.

Is the inspection result normal?

YES

>> Replace A/C auto amp. Refer to 

HAC-187, "Removal and Installation"

.

NO

>> Replace PTC heater outlet air and A/C unit case temperature sensor assembly. Refer to 

HAC-

198, "Removal and Installation"

.

5.

CHECK A/C UNIT CASE TEMPERATURE SENSOR POWER SUPPLY CIRCUIT FOR OPEN

1. Turn power switch OFF.

2. Disconnect A/C auto amp. connector. 

3. Check continuity between PTC heater outlet air and A/C unit case temperature sensor assembly harness

connector and A/C auto amp. harness connector. 

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Repair harness or connector.

6.

CHECK A/C UNIT CASE TEMPERATURE SENSOR POWER SUPPLY CIRCUIT FOR SHORT

+

−

Voltage

(Approx.)

PTC heater outlet air and A/C unit case temperature sensor as-

sembly

Connector

Terminal

M138

4

Ground

5 V

PTC heater outlet air and A/C unit case temperature 

sensor assembly

A/C auto amp.

Continuity

Connector

Terminal

Connector

Terminal

M138

3

M55

30

Yes

PTC heater outlet air and A/C unit case temperature 

sensor assembly

A/C auto amp.

Continuity

Connector

Terminal

Connector

Terminal

M138

4

M55

37

Yes