Subaru Legacy 2002 Service Manual page 3360

DIAGNOSTICS CHART WITH TROUBLE CODE (DTC)
Immobilizer (Diagnostics)
B: DTC P1572 IMM CIRCUIT FAILURE (EXCEPT ANTENNA CIRCUIT)
S009811H46
DIAGNOSIS:
¼ Communication failure between IMM ECM and ECM
WIRING DIAGRAM:
B6M1650
IM-15