Subaru forester 2004 Service Manual page 15

Diagnostics Chart for Immobilizer Warning Light
Step
1 CHECK POWER SUPPLY CIRCUIT.
1) Disconnect the harness connector from key
warning switch.
2) Measure the voltage between key warning
switch harness connector terminal and chassis
ground.
Connector & terminal
(B74) No. 2 (+) — Chassis ground (
2 CHECK KEY WARNING 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:
3 CHECK KEY WARNING 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:
4 CHECK HARNESS BETWEEN KEY WARN-
ING SWITCH AND IMM ECM.
1) Disconnect the harness connector from key
warning switch.
2) Disconnect the harness connector from
IMM ECM.
3) Measure the resistance between key warn-
ing switch harness connector terminal and
IMM ECM harness connector terminal.
Connector & terminal
(B74) No. 1 — (B141) No. 4:
Check
Is the voltage more than 10 V? Go to step 2.
−
):
Is the resistance less than 1
Ω?
Is the resistance more than
1 MΩ?
Is the resistance less than 10
Ω?
IM-13
IMMOBILIZER (DIAGNOSTIC)
Yes
Check the harness
for open or short
between key warn-
ing switch and
fuse.
Go to step 3. Replace the key
warning switch.
Go to step 4. Replace the key
warning switch.
Replace the IMM Repair the har-
ECM <Ref. to SL- ness between key
37, Immobilizer warning switch
Control Module.> and IMM ECM.
and then replace
all ignition keys
(including the tran-
sponder). Then
perform teaching
operation. Refer to
teaching opera-
tion manual (Pub.
No. S0820GZ).
No