Subaru Impreza 2004 Service Manual page 15

Step
1 CHECK FUSE.
1)Turn the ignition switch to OFF.
2)Remove the fuse No. 2 from main fuse box.
3)Check the condition of fuse.
2 CHECK FUSE.
1)Turn the ignition switch to OFF.
2)Remove the fuses No. 9 and No. 17 from
fuse & relay box.
3)Check the condition of fuse.
3 CHECK A/C CONTROL MODULE POWER
CIRCUIT.
1)Pull out the A/C control module connector.
2)Measure the voltage between A/C control
module connector terminal and chassis ground
when turning ignition switch to OFF.
Connector & terminal
(B283) No. 1 (+) — Chassis ground ( − − − − ):
4 CHECK A/C CONTROL MODULE POWER
CIRCUIT.
Measure the voltage between A/C control
module connector terminal and chassis ground
when turning the ignition switch to ACC.
Connector & terminal
(B283) No. 2 (+) — Chassis ground ( − − − − ):
5 CHECK A/C CONTROL MODULE POWER
CIRCUIT.
Measure the voltage between A/C control
module connector terminal and chassis ground
when turning the ignition switch to ON.
Connector & terminal
(B282) No. 8 (+) — Chassis ground ( − − − − ):
6 CHECK A/C CONTROL MODULE GROUND
CIRCUIT.
Measure the resistance of harness between A/
C control module and chassis ground.
Connector & terminal
(B283) No. 12 — Chassis ground:
7 CHECK POOR CONTACT.
Check poor contact in A/C control module con-
nector.
Diagnostics for A/C System Malfunction
Is the fuse blown-out?
Is the fuse blown-out?
Is the voltage more than 10 V? Go to step 4.
Is the voltage more than 10 V? Go to step 5.
Is the voltage more than 10 V? Go to step 6.
Is the resistance less than 5
Ω?
Is there poor contact in con-
nector?
AC(diag)-13
HVAC SYSTEM (AUTO A/C) (DIAGNOSTICS)
Check
Replace the fuse.
Replace the fuse.
Go to step 7.
Repair the con-
nector.
Yes No
Go to step 2.
Go to step 3.
Repair the short
circuit in harness
for power supply
line.
Repair the short
circuit in harness
for power supply
line.
Repair the short
circuit in harness
for power supply
line.
Repair the short
circuit in harness
for ground line.
Replace the A/C
control module.