Subaru Legacy 2002 Service Manual page 3364

DIAGNOSTICS CHART WITH TROUBLE CODE (DTC)
C: DTC P1574 KEY COMMUNICATION FAILURE
DIAGNOSIS:
¼ Failure of IMM ECM to verify key (transponder) ID code
No.
1 CHECK IMM ECM FUNCTION.
Insert the key to ignition switch (LOCK
position), measure changes in voltage
between antenna connector.
Connector & terminal
(B142) No. 1 — No. 2:
2 CHECK IGNITION KEY (TRANSPONDER).
1) Remove the key from ignition switch.
2) Start engine using other keys that have
undergone the teaching operation, furnished
with vehicle.
Step
Is the voltage −30 to 30 V?
(Approximately 0.1 second
after inserting the key.) Is
the voltage 0 V? (Approxi-
mately 1 second after
inserting the key.)
Does engine start?
IM-19
S009811H47
Check Yes
Go to step 2.
Replace ignition
key (including the
transponder).
Then perform
teaching opera-
tion. Refer to
teaching operation
manual (Pub. No.
S0820GZ).
Immobilizer (Diagnostics)
No
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).
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).