Subaru forester 2004 Service Manual page 24

Diagnostics Procedure with Diagnostic Trouble Code (DTC)
IMMOBILIZER (DIAGNOSTIC)
Step
1 CHECK ANTENNA CIRCUIT.
1) Turn the ignition switch to OFF.
2) Disconnect the harness antenna connector
from IMM ECM. <Ref. to SL-38, Immobilizer
Antenna.>
3) Measure the resistance of antenna circuit.
Connector & terminal
(B142) No. 1 — No. 2:
2 CHECK ANTENNA CIRCUIT.
Measure the resistance between antenna har-
ness connector and chassis ground.
Connector & terminal
(B142) No. 1 — Chassis ground:
3 CHECK ANTENNA CIRCUIT.
Measure the resistance between antenna har-
ness connector and chassis ground.
Connector & terminal
(B142) No. 2 — Chassis ground:
4 CHECK ANTENNA CIRCUIT.
1) Turn the ignition switch to ON. (engine
OFF.)
2) Measure the voltage between antenna har-
ness connector and chassis ground.
Connector & terminal
(B142) No. 1 (+) — Chassis ground(
5 CHECK ANTENNA CIRCUIT.
Measure the voltage between antenna har-
ness connector and chassis ground.
Connector & terminal
(B142) No. 2 (+) — Chassis ground(
6 CHECK IMM ECM FUNCTION.
1) Turn the ignition switch to OFF.
2) Connect the antenna harness connector to
IMM ECM.
3) Insert the key to ignition switch, measure
changes in voltage between antenna harness
connector.
Connector & terminal
(B142) No. 1 (+) — No. 2 (
7 CHECK IGNITION KEY (TRANSPONDER).
1) Remove the key from ignition switch.
2) Start the engine using other keys that have
undergone the teaching operation, furnished
with vehicle.
Is the resistance less than 10
Ω?
Is the resistance less than 10
Ω?
Is the resistance less than 10
Ω?
Is the voltage 0 V?
−
):
Is the voltage 0 V?
−
):
Is the voltage −30 to 30 V?
(Approx. 0.1 second after
inserting the key)
Is the voltage 0 V?
(Approx. 1 second after insert-
ing the key)
−
):
Does the engine start?
IM-22
Check
Go to step 2.
Replace the
antenna. <Ref. to
SL-38, Immobi-
lizer Antenna.>
Replace the
antenna. <Ref. to
SL-38, Immobi-
lizer Antenna.>
Go to step 5.
Go to step 6.
Go to step 7.
Replace the igni-
tion key (including
the transponder).
Then perform
teaching opera-
tion. Refer to the
teaching opera-
tion manual (Pub.
No. S0820GZ).
Yes No
Replace the
antenna. <Ref. to
SL-38, Immobi-
lizer Antenna.>
Go to step 3.
Go to step 4.
Replace the
antenna. <Ref. to
SL-38, Immobi-
lizer Antenna.>
Replace the
antenna. <Ref. to
SL-38, Immobi-
lizer Antenna.>
Replace the IMM
ECM <Ref. to SL-
37, Immobilizer
Control Module.>
and then replace
all ignition keys
(including the tran-
sponder). Then
perform teaching
operation. Refer to
the teaching oper-
ation manual (Pub.
No. S0820GZ).
Replace the IMM
ECM <Ref. to SL-
37, Immobilizer
Control Module.>
and then replace
all ignition keys
(including the tran-
sponder). Then
perform teaching
operation. Refer to
the teaching oper-
ation manual (Pub.
No. S0820GZ).