Subaru Legacy III (2000-2003 year). Manual - part 870

AC-16

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

SELF-DIAGNOSIS PROCEDURE (LHD MODEL)

1. OPERATING MODE TABLE

6

CHECK INDICATED VALUE OF EACH SEN-
SOR.
1) Turn temperature control dial clockwise by 

one click.

2) Each time the “DEF” switch is pressed, the 

value indicated on the display changes to 
correspond with the ambient sensor, in-
vehicle sensor and intake sensor, in that 
order.

3) Make sure there is no big difference 

between the temperature indicated on the 
display and the measured temperature.
Is a proper input signal value displayed in 
each sensor?

Proper input signal value dis-
played.

End

Go to step 7.

7

CHECK POOR CONTACT.
Check poor contact in A/C control module con-
nector.
Is there poor contact in connector?

There is no poor contact.

Replace A/C con-
trol module.

Repair connector.

Mode  display

41

42

43

44

45

46

47

48

Air inlet

REC

REC

REC

FRE

FRE

FRE

FRE

FRE

Air outlet

VENT

VENT

B/L

B/L

B/L

HEAT

D/H

DEF

Air mix door

FULL 

COOL

FULL 

COOL

FULL 

COOL

FULL HOT

FULL HOT

FULL HOT

FULL HOT

FULL HOT

Blower fan

5V

5V

Power sup-

ply voltage

8.5V

8.5V

8.5V

8.5V

Power sup-

ply voltage

A/C compressor

ON

ON

ON

OFF

OFF

OFF

ON

ON

Step

Value

Yes

No

AC-17

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

SELF-DIAGNOSIS PROCEDURE (LHD MODEL)

MEMO:

AC-18

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

SELF-DIAGNOSIS PROCEDURE (RHD MODEL)

6. Self-Diagnosis Procedure (RHD Model)

A: OPERATION

(1) Temperature control dial

(3) FRESH/RECIRC switch

(5) MODE switch

(2) AUTO switch

(4) DEF switch

Step

Value

Yes

No

1

SELECT CONTROL PANEL TO SELF-DIAG-
NOSIS MODE.
1) Turn ignition switch to OFF.
2) While pushing “AUTO” and “FRESH/

RECIRC” switches, turn ignition switch to 
ON.

3) Make sure that all characters on the display 

blinks four times.
Can it be moved to the self-diagnosis 
mode?

It can be moved to self-diagno-
sis mode.

Go to step 2.

<Ref. to AC-32, A/
C AND/OR SELF-
DIAGNOSIS SYS-
TEMS DO NOT 
OPERATE, Diag-
nostics for A/C 
System Failure 
(RHD Model).> 

AC-00362

OUT.TEMP

OUT.TEMP

MODE

AUTO

OFF

ECON

A/C

A/C

AUTO

BRIGHT

( 5 )

( 4 )

( 3 )

( 2 )

( 1 )

AC-19

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

SELF-DIAGNOSIS PROCEDURE (RHD MODEL)

1. OPERATING MODE TABLE

2

CHECK EACH SENSOR AND EACH POTEN-
TIOMETER.
1) When indicator check ends, it automatically 

switches to sensor and potentiometer 
check mode.

2) If system has the trouble for each sensor 

and/or each potentiometer, DTC is indi-
cated on indicator.

3) If system has no trouble, DTC “20” is indi-

cated on indicator.

NOTE:

When the sunload sensor is checked inside the
passenger compartment or in the shade, DTC
“25” may appear on the indicator. Always check
the sunload sensor in a place where it senses
direct sunlight.

NOTE:

Diagnosis code appears in order each time the
“A/C” switch is pushed.

Is the DTC “20” indicated on indicator?

DTC “20” is indicated on indi-
cator.

Go to step 3.

Perform diagnosis 
procedure accord-
ing to the dis-
played DTC. <Ref. 
to AC-49, DTC 
FOR SENSOR 
AND POTENTI-
OMETER, LIST 
(RHD MODEL), 
List of Diagnostic 
Trouble Code 
(DTC).>

3

CHECK OPERATION OF EACH ACTUATOR, 
BLOWER FAN AND COMPRESSOR 
CLUTCH.
1) After finishing sensor and potentiometer 

check modes, display goes to actuator 
check mode when “DEF” switch is pushed.

2) Operate the actuator displaying the DTCs 

two times within two seconds of each mode 
in order.

3) Select operating mode by pushing every 

“DEF” switch.

4) Check the operation for each mode.
• Air inlet:
• Air outlet:
• Air mix door:
• Blower fan:
• A/C compressor:

Does each mode displayed match the oper-
ating mode table? <Ref. to AC-19, OPER-
ATING MODE TABLE, OPERATION, Self-
Diagnosis Procedure (RHD Model).>

Each mode displayed matches 
the operating mode table.  

End

Go to step 4.

4

CHECK POOR CONTACT.
Check poor contact in A/C control module con-
nector.
Is there poor contact in connector?

There is no poor contact in A/C 
control module.

Replace A/C con-
trol module.

Repair connector.

Mode  display

31

32

33

34

35

36

37

38

Air inlet

FRE

REC

REC

FRE

FRE

FRE

FRE

FRE

Air outlet

VENT

VENT

VENT

B/L

HEAT

HEAT

D/H

DEF

Air mix door

FULL 

COOL

FULL 

COOL

FULL 

COOL

50%

50%

FULL HOT

FULL HOT

FULL HOT

Blower fan

LO

LO

ML

ML

ML

MH

MH

HI

A/C  compressor

OFF

ON

ON

ON

ON

ON

ON

ON

Step

Value

Yes

No