Fuel System Monitor (EVAP Leak Check Model)

OBD System Description - Fuel System Monitor (EVAP Leak Check Model)

Fuel System Description / Monitoring Procedure

As fuel system components age or otherwise change over the life of the vehicle, the adaptive fuel strategy learns deviations from stoichiometry while running in closed loop fuel. These learned corrections are stored in keep alive memory as long term fuel trim corrections. They continue to be changed and stored until they exceed normal limit or if a malfunction occurs, the long term fuel trim values will reach a rich or lean limit where the adaptive fuel strategy is no longer allowed to compensate for additional fuel system changes. Long term fuel trim corrections at their limits, in conjunction with a deviation in short term fuel trim, indicate a rich or lean fuel system malfunction.

Post Catalyst Fuel Trim System Description / Monitoring Procedure

The ECM monitors the A/F sensor characteristic offset by monitoring the feedback condition of HO2S. When the sum of correction factor of HO2S system exceeds higher or lower value, the ECM will set DTC.

DTC Description / Detecting Condition / Confirmation Procedure

P0171, P0172

Refer to P0171 DTC P0171 / P0172.

P2096, P2097

Refer to P2096 DTC P2096 / P2097.

Fuel System Monitor

Operation









Enable conditions





Typical malfunction thresholds