Subaru Legacy 2003 Service Manual page 17

DIAGNOSTIC PROCEDURE FOR IMMOBILIZER INDICATOR LIGHT
Step
1 CHECK POWER SUPPLY CIRCUIT.
1) Disconnect harness connector from key
warning switch.
2) Measure voltage between key warning
switch harness connector terminal and
chassis ground.
Connector & terminal
(B74) No. 2 (+) — Chassis ground ( − − − − ):
Does the measured value exceed the spec-
ified value?
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.
Terminal
No. 1 — No. 2:
Is the measured value less than the speci-
fied value?
3 CHECK KEY SWITCH.
1) Remove the ignition key from the ignition
switch.
2) Measure the resistance between key warn-
ing switch connector terminals.
Terminal
No. 1 — No. 2:
Does the measured value exceed the spec-
ified value?
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:
Is the measured value less than the speci-
fied value?
Value
10 V
1 Ω
1 MΩ
10 Ω
IM-15
IMMOBILIZER (DIAGNOSTICS)
Yes
Go to step 2. Check harness for
open or short
between key warn-
ing switch and
fuse.
Go to step 3. Replace key warn-
ing switch.
Go to step 4. Replace key warn-
ing switch.
Replace IMM ECM Repair harness
<Ref. to SL-36, between key warn-
Immobilizer Con- ing switch and
trol Module.> and IMM ECM.
then replace all
ignition keys
(including the tran-
sponder). Then
perform teaching
operation. Refer to
teaching opera-
tion manual (Pub.
No. S0820GZ).
No