Subaru Legacy 2002 Service Manual page 3357

DIAGNOSTICS CHART FOR IMMOBILIZER INDICATOR LIGHT
Immobilizer (Diagnostics)
No.
1 CHECK POWER SUPPLY CIRCUIT.
1) Disconnect harness connector from key
warning switch.
2) Turn ignition switch ACC or LOCK position
(The key inserted).
3) Measure voltage between key warning
switch harness connector terminal and chas-
sis ground.
Connector & terminal
(B74) No. 2 (+) — Chassis ground (−):
2 CHECK KEY SWITCH.
1) Insert the ignition key to the ignition switch.
(OFF or ACC position)
2) Measure the resistance between key warn-
ing switch connector terminals.
Connector & terminal
No. 1 — No. 2:
3 CHECK KEY SWITCH.
1) Remove the ignition key from the ignition
switch.
2) Measure the resistance between key warn-
ing switch connector terminals.
Connector & terminal
No. 1 — No. 2:
4 CHECK HARNESS BETWEEN KEY SWITCH
AND IMM ECM.
1) Disconnect harness connector from key
warning switch.
2) Disconnect harness connector from IMM
ECM.
3) Measure resistance between key warning
switch harness connector terminal and IMM
ECM harness connector terminal.
Connector & terminal
(B74) No. 1 — (B141) No. 4:
Step
Is the voltage more than 10
V?
Is the resistance less than
1 Ω?
Is the resistance more than
1 MΩ?
Is the resistance less than
10 Ω?
IM-12
Check Yes
Go to step 2.
Go to step 3.
Go to step 4.
Replace IMM
ECM <Ref. to
SL-35, Immobi-
lizer Control Mod-
ule.> and then
replace all ignition
keys (including
the transponder).
Then perform
teaching opera-
tion. Refer to
teaching operation
manual (Pub. No.
S0820GZ).
No
Check harness for
open or short
between key
warning switch
and fuse.
Replace key
warning switch.
Replace key
warning switch.
Repair harness
between key
warning switch
and IMM ECM.