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 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 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 amount reaches excessive levels because of a lean or rich condition.
DTC Description
ECM sets DTC P2191 if ECM monitors and detects fuel adaptation value is higher than specifications while vehicle is not in idle condition.
DTC Detecting Condition
Item | Detecting Condition | Possible Cause |
DTC Strategy | Check the revised air-fuel-ratio
| Air leakage
Improper fuel pressure
PCV valve stuck
Clogging of injector
|
Enable Conditions | 30% = load = 75%
1200 = Engine speed = 3520rpm
40kg/h = Mass of air flow= 200kg/h
|
Threshold Value | Long Term FT (multiplicative) > 1.23
|
Diagnostic Time | 30 sec
|
MIL ON Condition | 3 driving cycle
|