Subaru 2009 IMPREZA Service Manual page 735

Diagnostic Trouble Code (DTC) Detecting Criteria
C: DTC P0030 HO2S HEATER CONTROL CIRCUIT (BANK 1 SENSOR 1)
1. OUTLINE OF DIAGNOSIS
Detect functional errors of the front oxygen (A/F) sensor heater.
Judge as NG when it is determined that the front oxygen (A/F) sensor impedance is large when looking at en-
gine status such as deceleration fuel cut.
2. COMPONENT DESCRIPTION
(1) (2) (3) (4)
(1) Element cover (outer)
(2) Element cover (inner)
3. ENABLE CONDITIONS
Secondary Parameters
Condition established time
Battery voltage
Heater current
Control duty 35 %
After fuel cut
4. GENERAL DRIVING CYCLE
Perform the diagnosis continuously after 42000 ms seconds or more have passed since the engine started.
(5)
(3) Sensor element
(4) Ceramic heater
Enable Condition
42000 ms
10.9 V
Permitted
Experienced
20000 ms
GD(H4SO)-11
GENERAL DESCRIPTION
(5) Sensor housing
EN-01683