Subaru Forester 2004 - Page 94

AC-40
HVAC SYSTEM (AUTO A/C)(DIAGNOSTIC)
Diagnostic Procedure for Sensors
Step Check Yes No
1 CHECK POWER SUPPLY VOLTAGE FOR
SUNLOAD SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from sunload
sensor.
3) Turn the ignition switch to ON.
4) Measure the power supply voltage for sun-
load sensor.
Connector & terminal
(i51) No. 2 (+) — Chassis ground (
− ):
Is the voltage approx. 5 V? Go to step 4. Go to step 2.
2 CHECK AUTO A/C CONTROL MODULE
OUTPUT SIGNAL.
1) Turn the ignition switch to OFF.
2) Remove the auto A/C control module.
3) Turn the ignition switch to ON.
4) Measure the voltage between connector
terminals of auto A/C control module.
Connector & terminal
(i49) No. 3 (+) — (i48) No. 16 (
− ):
Is the voltage approx. 5 V? Go to step 3. Go to step 6.
3 CHECK HARNESS CONNECTOR BETWEEN
AUTO A/C CONTROL MODULE AND SUN-
LOAD SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from auto A/C
control module.
3) Measure the resistance in harness
between auto A/C control module and sunload
sensor.
Connector & terminal
(i51) No. 2 — (i49) No. 3:
Is the resistance less than 1
Ω?
Go to step 4. Repair the har-
ness between auto
A/C control mod-
ule and sunload
sensor.
4 CHECK HARNESS CONNECTOR BETWEEN
AUTO A/C CONTROL MODULE AND SUN-
LOAD SENSOR.
Measure the resistance in harness between
auto A/C control module and sunload sensor.
Connector & terminal
(i51) No. 1 — (i48) No. 16:
Is the resistance less than 1
Ω?
Go to step 5. Repair the har-
ness between auto
A/C control mod-
ule and sunload
sensor.
5 CHECK INPUT VOLTAGE FOR AUTO A/C
CONTROL MODULE.
1) Connect the connector of auto A/C control
module.
2) Turn the ignition switch to ON.
3) Measure the voltage between connector
terminals of auto A/C control module.
Connector & terminal
(i49) No. 3 (+) — (i48) No. 16 (
− ):
Is the voltage approx. 2.5 V? Go to step 6. Replace the sun-
load sensor.
6 CHECK POOR CONTACT.
Check poor contact in auto A/C control module
connector.
Is there poor contact in con-
nector?
Repair the con-
nector.
Replace the auto
A/C control mod-
ule.