General Information

General Description

In order to provide the best possible combination of drivability, fuel economy, and emission control, the ECM uses a closed loop air/fuel metering system. The ECM monitors the HO2S signal voltage and adjusts the fuel delivery based on the HO2S signal voltage in closed loop fuel control. Changes in fuel delivery will be indicated by the short-term and the long-term fuel trim values. The ideal fuel trim value is around 0%. The ECM will add fuel when the HO2S signal is indicating a lean condition. Additional fuel is indicated by fuel trim values that are above 0%. The ECM will reduce fuel when the HO2S signal is indicating a rich condition. Reduction in fuel is indicated by fuel trim values that are below 0%. The DTC relevant to fuel trim will be set when the value reaches excessive levels because of a lean or rich condition.

DTC Description

The ECM monitors the trim of lambda control by the rear HO2S signal in addition to the HO2S monitoring. The trim value calculation is based on the difference of rear HO2S signal from desired value. The ECM sets DTC P2097 if either trim value or the difference of rear HO2S from desired value is reached to the minimum threshold.
If the same error code is set in the next driving cycle, the ECM illuminates the MIL.

DTC Detecting Condition





Schematic Diagram





Signal Waveform