General Information

Engine Control

P2272 O2 Sensor Signal Stuck Lean (Bank 2 Sensor 2) - General Information

Component Location





General Description

The rear heated oxygen sensor is mounted on the rear side of the Catalytic Converter (warm-up catalytic converter) or in the rear exhaust pipe, which is able to detect catalyst efficiency. The rear heated oxygen sensor (HO2S) produces a voltage between 0 V and 1 V. This rear heated oxygen sensor is used to estimate the oxygen storage capability. If a catalyst has good conversion properties, the oxygen fluctuations are smoothed by the oxygen storage capacity of the catalyst. If the conversion provided by the catalyst is low due to aging, poisoning or misfiring, then the oxygen fluctuations are similar to signals from the front oxygen sensor.

DTC Description

ECM set P2272 code if output signal is too low at DOWN O2 sensor when AIR-FUEL ratio is under thick condition.

DTC Detecting Condition





Specification





Diagnostic Circuit Diagram





Signal Waveform & Data




Fig.1) Normal waveforms of front HO2S (the upper) and rear HO2S (the lower)
After warming-up, if accelerator pedal is released suddenly around 4000 rpm, the HO2S signal reading will be lower than 200 mV resulting from Fuel cut-off for the moment. Conversely, if suddenly accelerator pedal is depressed, HO2S signal reading will be around 0.6V ~ 1.0 V. At idle, Normally HO2S signal will switch from lean to rich with 3 Hz. And as racing, Its frequency rises.