DTC P2096 POST CATALYST FUEL TRIM SYSTEM TOO LEAN (BANK 1)
In order to provide the best possible combination of driveability, fuel economy and emission control, the ECM uses a closed loop air/fuel metering system. It monitors the HO2S signal voltage and adjusts fuel delivery based 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.
If the lambda controller reaches the maximum or minimum threshold, then feedback control is no longer possible and emissions will be increased. The ECM sets DTC P2096 if no proportional post catalyst fuel trim adaptation occurs for a defined time after the lambda controller has reached its maximum threshold.
Possible causes :
1. Air leak in exhaust system.
2. Faulty HO2S
3. Faulty two way catalytic converter.
DTC DETECTING CONDITION
ItemDetecting ConditionPossible Cause
DTC StrategyMonitoring deviation of
down HO2S feedback
Air leakage in exhaust
Lambda control active
No relevant failure
Dynamic fuel trim is
Canister purge valve
not opening or closing
Threshold ValueAdaptation value > 630
Diagnostic Time60 sec.
MIL On Condition2 Driving Cycles
Sunday, March 6th, 2011 AT 2:26 PM