Subaru Impreza 3 / Impreza WRX / Impreza WRX STI. Manual — part 601

AC(diag)-9

Diagnostic Chart for Self-Diagnosis

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

5. Diagnostic Chart for Self-Diagnosis

A: OPERATION

1. A/C CONTROL MODULE SELF-DIAGNOSIS

(1)

Fan dial

(3)

Temperature adjustment dial

(5)

Rear window defogger switch

(2)

Air flow control dial

(4)

FRESH/RECIRC switch

(6)

A/C switch

Step

Check

Yes

No

1

SELECT SELF-DIAGNOSIS MODE IN THE
CONTROL MODULE.
1) Set the air flow control dial and fan dial to the
AUTO position.
2) Start the engine with the A/C switch and the
FRESH/RECIRC switch pressed.

Does the self-diagnosis mode
operate?

Go to step

2.

<Ref. to AC(diag)-
13, A/C OR SELF-
DIAGNOSIS SYS-
TEMS DO NOT
OPERATE, Diag-
nostics for A/C
System Malfunc-
tion.>

2

CHECK THE LIGHTING OF THE LED.
Make sure that all switch LEDs on the control
module illuminate.

Do all LEDs blink eight times? Go to step

3.

Replace the con-
trol module.

3

CHECK SENSOR MALFUNCTION.
1) Set the air flow control dial and fan dial to the
AUTO position.
2) If the system has trouble for each sensor,
the FRESH/RECIRC switch LED blinks or is
turned off.
3) If the system has no malfunctions, the
FRESH/RECIRC switch LED is illuminated.

Does the FRESH/RECIRC
switch LED illuminate?

Go to step

5.

Go to step

4.

4

CONFIRM MALFUNCTIONING SENSOR.
1) Set the air flow control dial to AUTO.
2) Turn the fan dial to each mode position, and
check each switch LED illumination according
to sensor check table. <Ref. to AC(diag)-11,
SENSOR CHECK TABLE, OPERATION, Diag-
nostic Chart for Self-Diagnosis.>

When turning the fan dial to
each mode position, does the
FRESH/RECIRC switch LED
go off?

Go to step

5.

Repair the defec-
tive sensor. <Ref.
to AC(diag)-29,
Diagnostic Proce-
dure for Sensors.>

(5)

(2)

(6)

(1)

(4)

(3)

AC-02014

AC(diag)-10

Diagnostic Chart for Self-Diagnosis

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

5

CHECK AIR MIX DOOR AND MODE DOOR
POSITION SIGNALS.
1) Set the air flow control dial to FACE.
2) Turn the fan dial to AUTO.
3) If there is a system malfunction in the air mix
door signal or the mode door position signal, the
FRESH/RECIRC switch LED goes off or blinks.
4) If the system has no malfunctions, the
FRESH/RECIRC switch LED is illuminated.

Does the FRESH/RECIRC
switch LED illuminate?

Go to step

8.

Go to step

6.

6

CHECK AIR MIX DOOR POSITION DRIVE
SIGNALS.
1) Set the air flow control dial to FACE.
2) Place the fan dial in each position and then
check each LED illumination conditions. <Ref.
to AC(diag)-12, DRIVE SIGNAL CHECK
TABLE, OPERATION, Diagnostic Chart for
Self-Diagnosis.>

Do the LEDs illuminate in
accordance with operation sig-
nal table?

Go to step

7.

Check the air mix
door actuator cir-
cuit. <Ref. to
AC(diag)-27, AIR
MIX DOOR ACTU-
ATOR, Diagnostic
Procedure for
Actuators.>

7

CHECK MODE DOOR POSITION DRIVE SIG-
NAL.
1) Press the A/C switch.
2) Place the fan dial in each position and then
check each LED illumination conditions. <Ref.
to AC(diag)-12, DRIVE SIGNAL CHECK
TABLE, OPERATION, Diagnostic Chart for
Self-Diagnosis.>

Do the LEDs illuminate in
accordance with operation sig-
nal table?

Go to step

8.

Check the mode
door actuator cir-
cuit. <Ref. to
AC(diag)-25,
MODE DOOR
ACTUATOR, Diag-
nostic Procedure
for Actuators.>

8

CHECK OPERATION OF EACH ACTUATOR,
BLOWER FAN AND COMPRESSOR
CLUTCH.
1) Set the air flow control dial to B/L.
2) Turn the fan dial from AUTO to 7th, and
select operating modes.
3) Check the operation of each mode accord-
ing to operating mode table. <Ref. to AC(diag)-
12, OPERATING MODE TABLE, OPERATION,
Diagnostic Chart for Self-Diagnosis.>
• FRESH/RECIRC door
• Air flow control door
• Air mix door
• Blower fan
• A/C compressor

Does the operation of each
mode match to operating mode
table?

Turn the fan dial to
OFF or the ignition
switch to OFF in
order to complete
self-diagnosis.

Repair the mal-
functioning part in
accordance with
each diagnostic
chart.

Step

Check

Yes

No

AC(diag)-11

Diagnostic Chart for Self-Diagnosis

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

2. SENSOR CHECK TABLE

NOTE:

• When the sunload sensor check is performed indoors or in the shade, it could be diagnosed as having an

open circuit. Always check the sunload sensor at a location exposed to direct sunlight.

• LED illuminates to warn the past malfunction if it was detected four times or more in the past.

• To clear the past malfunction, disconnect the ground cable from the battery, or press and hold the FRESH/

RECIRC switch for five seconds or more when performing the self-diagnosis Step 3 to Step 7.

Air flow control

dial position

Fan dial

position

Sensor

No trouble

Short circuit

Open circuit

When cur-
rently mal-

functioning

When hav-

ing malfunc-
tioned in the

past

AUTO

AUTO

In-vehicle sen-

sor

FRESH/

RECIRC

switch LED is

turned off

FRESH/

RECIRC

switch LED

blinks (Illumi-

nates for 0.2

sec. ←→

turns off for

0.2 sec.)

FRESH/

RECIRC

switch LED

blinks (Illumi-

nates for 1

sec. ←→

turns off for 1

sec.)

Rear window

defogger

switch LED is

turned off

Rear window

defogger

switch LED

illuminates

1st

Ambient sensor

FRESH/

RECIRC

switch LED

blinks (Illumi-

nates for 0.2

sec. ←→

turns off for

0.2 sec.)

2nd

Evaporator sen-

sor

FRESH/

RECIRC

switch LED

blinks (Illumi-

nates for 0.2

sec. ←→

turns off for

0.2 sec.)

3rd

Engine coolant

temperature

sensor

—

4th

Sunload sensor

FRESH/

RECIRC

switch LED

blinks (Illumi-

nates for 0.2

sec. ←→

turns off for

0.2 sec.)

5th — 7th

CAN communi-

cation

—

AC(diag)-12

Diagnostic Chart for Self-Diagnosis

HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)

3. OPERATING MODE TABLE

4. DRIVE SIGNAL CHECK TABLE

NOTE:

• LED illuminates to warn the past malfunction if it was detected four times or more in the past.

• To clear the past malfunction, disconnect the ground cable from the battery, or press and hold the FRESH/

RECIRC switch for five seconds or more when performing the self-diagnosis Step 3 to Step 7.

Operation

Fan dial position

AUTO

1st

2nd

3rd

4th

5th

6th

7th

Blower fan

4 V

4 V

4.9 V

5.9 V

7.0 V

8.3 V

9.8 V

14 V

FRESH/RECIRC
door

RECIRC

RECIRC

MIX

FRESH

FRESH

FRESH

FRESH

FRESH

Air flow control
door

FACE

FACE

FACE

B/L

HEAT

HEAT

D/H

DEF

Air mix door

0%

0%

0%

50%

50%

100%

100%

100%

A/C compressor

OFF

ON

ON

ON

ON

ON

ON

ON

Air flow

control dial

position

Fan dial
position

Drive signal

to check

A/C

switch

LED

No trouble

Short circuit

Open circuit

When cur-

rently mal-

functioning

When hav-

ing malfunc-
tioned in the

past

FACE

AUTO

MIX

#1

Blinking

(Illumi-

nates for

0.2 sec.

←→ turns

off for 0.2

sec.)

FRESH/

RECIRC

switch LED is

turned off

FRESH/

RECIRC

switch LED

blinks (Illumi-

nates for 0.2

sec. ←→

turns off for

0.2 sec.)

FRESH/

RECIRC

switch LED

blinks (Illumi-

nates for 1

sec. ←→

turns off for

1 sec.)

Rear window

defogger

switch LED is

turned off

Rear window

defogger

switch LED

illuminates

1st

MIX

#2

2nd

MIX

#3

3rd —
7th

MIX

#4

AUTO

MODE

#1

Blinking

(Illumi-

nates for

1 sec.

←→ turns

off for 1

sec.)

1st

MODE

#2

2nd

MODE

#3

3rd —
7th

MODE

#4