Subaru Legacy 2004 Service Manual page 3443

Step
1 CHECK AMBIENT SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from ambient
sensor.
3) Measure the resistance between connector
terminals of ambient sensor.
Terminals
No. 1 — No. 2:
2 CHECK INPUT SIGNAL FOR AMBIENT SEN-
SOR.
1) Turn the ignition to ON.
2) Measure the voltage between connector
(F78) terminals.
Connector & terminal
(F78) No. 1 (+) — No. 2 (
3 CHECK OUTPUT SIGNAL OF BODY INTE-
GRATED UNIT.
1) Turn the ignition switch to OFF.
2) Draw out the body integrated unit.
3) Disconnect the connector from ambient
sensor.
4) Turn the ignition switch to ON.
5) Measure the voltage between connector
terminals of body integrated unit.
Connector & terminal
(B281) No. 3 (+) — No. 10 (
4 CHECK HARNESS CONNECTOR BETWEEN
BODY INTEGRATED UNIT AND AMBIENT
SENSOR.
1) Turn the ignition switch to OFF.
2) Disconnect the connector from body inte-
grated unit.
3) Measure the resistance in harness
between body integrated unit and ambient sen-
sor.
Connector & terminal
(F78) No. 1 — (B281) No. 10:
5 CHECK HARNESS CONNECTOR BETWEEN
BODY INTEGRATED UNIT AND AMBIENT
SENSOR.
Measure the resistance in harness between
body integrated unit and ambient sensor.
Connector & terminal
(F78) No. 2 — (B281) No. 3:
6 CHECK COMMUNICATION ERROR DIS-
PLAY.
1) Connect the connectors of body integrated
unit and ambient sensor to original position.
2) Check "Er xx" is indicated on the Odo/Trip
meter in combination meter after turning the
ignition switch to ON.
7 CHECK POOR CONTACT.
Check poor contact in auto A/C control module
connector.
Diagnostic Procedure for Sensors
Is the resistance approx. 2.2
k# at 25!C (77!F)?
Is the voltage approx. 5 V?
$
):
Is the voltage approx. 5 V?
$
):
Is the resistance less than 1
#?
Is the resistance less than 1
#?
Is the error display "Er xx" indi-
cated?
Is there poor contact in con-
nector?
AC(diag)-31
HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)
Check Yes
Go to step 2.
Go to step 6.
Go to step 4.
Go to step 5.
Go to step 6.
Check the commu-
nication circuit.
<Ref. to
LAN(diag)-2, Basic
Diagnostic Proce-
dure.>
Repair the con-
nector.
No
Replace the ambi-
ent sensor.
Go to step 3.
Go to step 6.
Repair the open
circuit in harness
between body inte-
grated unit and
ambient sensor.
Repair the open
circuit in harness
between body inte-
grated unit and
ambient sensor.
Go to step 7.
Replace the A/C
control module.