Subaru Legacy III (2000-2003 year). Manual - part 866

AC-52

HVAC SYSTEM (HEATER, VENTILATOR AND A/C)

GENERAL DIAGNOSTICS

25.General Diagnostics

A: INSPECTION

Symptom

Repair order

Blower motor

Doesn't move.

Fuse

Blower motor relay

Blower motor

Blower motor resistor

Blower switch

Wire harness

Strange noise.

Blower motor

Compressor

Doesn't move.

Refrigerant

Fuse

Air conditioning relay

Magnet clutch

Compressor

Pressure switch

A/C switch

Blower switch

Wire harness

Strange noise

V-Belt

Magnet clutch

Compressor

Cold air not emitted.

Refrigerant

V-Belt

Magnet clutch

Compressor

Pressure switch

A/C switch

Blower switch

Wire harness

Heater duct

Heater vent duct

Warm air not emitted.

Engine coolant

Blower switch

Heater core

Temperature of air from vents does not change.

Engine coolant

Mode actuator

Wire harness

Unable to switch blow vents.

Mode actuator

Air flow switch

Wire harness

Unable to switch suction vents.

Air inlet select switch

FRESH/RECIRC actuator

Wire harness

HVAC SYSTEM (AUTO A/C) 
(DIAGNOSTICS)

AC

Page

1.

Basic Diagnostic Procedure ..............................................................................2

2.

General Description ..........................................................................................5

3.

Electrical Components Location........................................................................8

4.

A/C Control Module I/O Signal ........................................................................10

5.

Self-Diagnosis Procedure (LHD Model) ..........................................................14

6.

Self-Diagnosis Procedure (RHD Model) .........................................................18

7.

Diagnostics for A/C System Failure (LHD Model) ...........................................20

8.

Diagnostics for A/C System Failure (RHD Model) ..........................................32

9.

List of Diagnostic Trouble Code (DTC) ...........................................................49

10.

Diagnostic Procedure with Diagnostic Trouble Code (DTC) (LHD Model)......50

11.

Diagnostic Procedure with Diagnostic Trouble Code (DTC) (RHD Model) .....65

12.

Symptom Related Diagnostic..........................................................................79

AC-2

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

BASIC DIAGNOSTIC PROCEDURE

1. Basic Diagnostic Procedure

A: PROCEDURE

Step

Value

Yes

No

1

START INSPECTIONS.
1) Perform pre-inspection.
2) Perform self-diagnosis.

LHD: <Ref. to AC-14, OPERATION, Self-
Diagnosis Procedure (LHD Model).>
RHD: <Ref. to AC-18, OPERATION, Self-
Diagnosis Procedure (RHD Model).>
Dose self-diagnosis operate?

Self-diagnosis operates.

Go to step 2.

LHD: <Ref. to AC-
20, A/C AND/OR 
SELF-DIAGNO-
SIS SYSTEMS 
DO NOT OPER-
ATE, Diagnostics 
for A/C System 
Failure (LHD 
Model).>  RHD: 
<Ref. to AC-32, A/
C AND/OR SELF-
DIAGNOSIS SYS-
TEMS DO NOT 
OPERATE, Diag-
nostics for A/C 
System Failure 
(RHD Model).>  

2

CHECK DTC.
Check DTC.
Is DTC indicated?

DTC indicated.

LHD: <Ref. to AC-
50, Diagnostic 
Procedure with 
Diagnostic Trou-
ble Code (DTC) 
(LHD Model).>  
RHD:<Ref. to AC-
65, Diagnostic 
Procedure with 
Diagnostic Trou-
ble Code (DTC) 
(RHD Model).>  

Go to step 3.

3

CHECK BLOWER MOTOR OPERATION.
1) Turn blower switch ON.
2) Check blower motor operation.

Is blower motor rotated?

Blower motor rotates.

Go to step 4.

LHD: <Ref. to AC-
22, BLOWER 
MOTOR DOES 
NOT ROTATE, 
Diagnostics for A/
C System Failure 
(LHD Model).> 
RHD: <Ref. to AC-
34, BLOWER 
MOTOR DOES 
NOT ROTATE, 
Diagnostics for A/
C System Failure 
(RHD Model).> 
and  <Ref. to AC-
38, BLOWER 
MOTOR 
ROTATES 
ABNORMALLY, 
Diagnostics for A/
C System Failure 
(RHD Model).>

AC-3

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

BASIC DIAGNOSTIC PROCEDURE

4

CHECK FRESH/RECIRC MODE.
Change FRESH/RECIRC mode by pushing 
mode switch.
Is FRESH/RECIRC mode changed?

FRESH/RECIRC mode 
changes.

Go to step 5.

LHD: <Ref. to AC-
30, FRESH/
RECIRC DOES 
NOT CHANGE, 
Diagnostics for A/
C System Failure 
(LHD Model).> 
RHD: <Ref. to AC-
41, FRESH/
RECIRC DOES 
NOT CHANGE, 
Diagnostics for A/
C System Failure 
(RHD Model).>  

5

CHECK COMPARTMENT TEMPERATURE.
1) Turn A/C switch ON.
2) Set temperature at 18

°

C (65

°

F) (FULL 

COOL).

3) Check compartment temperature changes.

Is the compartment temperature changed?

Compartment temperature 
changes.

Go to step 6.

LHD: <Ref. to AC-
24, COMPART-
MENT TEMPERA-
TURE DOES NOT 
CHANGE FROM 
“SET” TEMPERA-
TURE OR AIR 
CONDITIONING 
SYSTEM DOES 
NOT RESPOND 
QUICKLY, Diag-
nostics for A/C 
System Failure 
(LHD Model).>  
RHD: <Ref. to AC-
44, COMPART-
MENT TEMPERA-
TURE DOES NOT 
CHANGE FROM 
“SET” TEMPERA-
TURE OR AIR 
CONDITIONING 
SYSTEM DOES 
NOT RESPOND 
QUICKLY, Diag-
nostics for A/C 
System Failure 
(RHD Model).>  

Step

Value

Yes

No