In order to provide the best possible combination of drivability, fuel economy and emission control, the ECM/PCM uses a closed loop air/fuel metering system. The ECM/PCM monitors the HO2S signal voltage and adjusts fuel delivery based it in closed loop fuel control. Changes in fuel delivery will be indicated by the long-term and the short-term fuel trim values. The ideal fuel trim value is around 0%. The ECM/PCM 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/PCM 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 amount reaches excessive levels because of a lean or rich condition.
ECM/PCM assumes Lambda sensor is out of control and shows P2195 when upstream O2 sensor displays rich condition in spite of continuous correcting by downstream O2 sensor.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Check the revised air-fuel-ratio | 1. Poor connection 2. S1 3. Blocking of intake system 4. Fuel leakage in injector 5. Improper fuel pressure |
Enable Conditions |
•
Engine speed 1120~3000rpm
•
480℃ < Catalyst temp.(model) < 800℃ | |
Threshold Value |
•
Deviation value of air fuel ratio control < - 0.07 | |
Diagnostic Time |
•
- | |
MIL ON Condition |
•
2 driving cycles |
