DTC P2096: Post Catalyst Fuel Trim System Too Lean (Bank 1); DTC P2097: Post Catalyst Fuel Trim System Too Rich (Bank 1) [06/2016 - 12/2017]: Description
The sub fuel trim is related to the feedback compensation value, not to the basic injection time. The sub fuel trim consists of both the short-term and the long-term fuel trim between the front catalyst and rear catalyst.
The short-term fuel trim is fuel compensation that is used to constantly maintain the air fuel ratio at stoichiometric levels. The signal from the air fuel ratio sensor indicates whether the air fuel ratio is rich or lean compared to the stoichiometric ratio. This triggers a reduction in the fuel injection volume if the air fuel ratio is rich and an increase in the fuel injection volume if it is lean.
Factors such as individual engine differences, wear over time and changes in operating environment cause short-term fuel trim to vary from the ideal theoretical value. The long-term fuel trim controls overall fuel compensation. The long-term fuel trim compensates for long term deviations of the fuel trim from the ideal theoretical value. These long term deviations result from the corrections made by the short-term fuel trim.
If both the short-term fuel and long-term fuel trim are lean or rich beyond predetermined values, it is interpreted as a malfunction, the ECM illuminates the MIL and sets a DTC.
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| P2096 | With warm engine and stable air fuel ratio feedback, sub fuel trim considerably in error to lean side. (2 trip detection logic) |
|
| P2097 | With warm engine and stable air fuel ratio feedback, sub fuel trim considerably in error to rich side. (2 trip detection logic) |
HINT:
- When DTC P2096 is set, the actual air-fuel ratio is on the lean side. When DTC P2097 is set, the actual air-fuel ratio is on the rich side.
- If the vehicle runs out of fuel, the air-fuel ratio is lean and DTC P2096 may be set. The MIL is then illuminated.