Subaru 2002 IMPREZA Service Manual page 587

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
Step
1 CHECK ANY OTHER DIAGNOSTIC TROU-
BLE CODE (DTC) ON DISPLAY.
Check
Is any other DTC displayed?
EN-155
ENGINE (DIAGNOSTICS)
Yes
Inspect the rele- Replace the rear
vant DTC using oxygen sensor.
"List of Diagnostic <Ref. to FU-47,
Trouble Code Front Oxygen (A/
(DTC)". <Ref. to F) Sensor.>
EN-83, List of
Diagnostic Trou-
ble Code (DTC).>
NOTE:
In this case, it is
not necessary to
inspect DTC
P0139.
No