Subaru Impreza 2003 Service Manual page 1314

DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)
ENGINE (DIAGNOSTICS)
Step
1 CHECK ANY OTHER DTC ON DISPLAY.
2 CHECK EXHAUST SYSTEM.
NOTE:
Check the following items.
•Loose installation of front portion of exhaust
pipe onto cylinder heads
•Loose connection between front exhaust pipe
and front catalytic converter
•Damage of exhaust pipe resulting in a hole
Z: DTC P0134 — O
SENSOR 1) —
NOTE:
For the diagnostic procedure, refer to DTC P0130. <Ref. to EN(H4DOTC)-135, DTC P0130 — O
CIRCUIT (BANK 1 SENSOR 1) —, Diagnostic Procedure with Diagnostic Trouble Code (DTC).>
Is any other DTC displayed?
Is there a fault in exhaust sys-
tem?
SENSOR CIRCUIT NO ACTIVITY DETECTED (BANK 1
2
EN(H4DOTC)-138
Check
Inspect the rele-
vant DTC using
"List of Diagnostic
Trouble Code
(DTC)". <Ref. to
EN(H4DOTC)-75,
List of Diagnostic
Trouble Code
(DTC).>
NOTE:
In this case, it is
not necessary to
inspect
P0133.
Repair the exhaust
system.
Yes No
Go to step 2.
DTC
Replace the front
oxygen (A/F) sen-
sor. <Ref. to
FU(H4DOTC)-44,
Front Oxygen (A/
F) Sensor.>
SENSOR
2