Subaru 2002 IMPREZA Service Manual page 1317

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK ANY OTHER DIAGNOSTIC TROU-
BLE CODE (DTC) ON DISPLAY.
Check
In any other DTC displayed?
EN(TURBO)-157
ENGINE (DIAGNOSTICS)
Yes
Inspect the rele- Replace the rear
vant DTC using oxygen sensor.
"List of Diagnostic <Ref. to
Trouble Code FU(TURBO)-46,
(DTC)". <Ref. to Rear Oxygen Sen-
EN(TURBO)-75, sor.>
List of Diagnostic
Trouble Code
(DTC).>
NOTE:
In this case, it is
not necessary to
inspect DTC
P0139.
No