Subaru 2009 IMPREZA Service Manual page 880

Diagnostic Trouble Code (DTC) Detecting Criteria
GENERAL DESCRIPTION
CI: DTC P1152 O2 SENSOR CIRCUIT RANGE/PERFORMANCE (LOW)
(BANK1 SENSOR1)
1. OUTLINE OF DIAGNOSIS
Detect that value remains low.
Judge as NG when lambda value is abnormal in accordance with
running conditions such as vehicle speed, amount of intake air, engine coolant temperature, sub feedback
control, etc.
value = Actual air fuel ratio/Theoretical air fuel ratio
> 1: Lean
< 1: Rich
2. COMPONENT DESCRIPTION
(2)
(4)
(A) Electromotive force
(D) Rich
(1) Atmosphere
(2) Exhaust gas
(3)
(1)
(2)
(B) Air fuel ratio
(3) ZrO
2
GD(H4SO)-156
value of front oxygen (A/F) sensor and
(A)
(C)
(C) Lean
(4) Ceramic heater
(B) (D)
EN-01693