Mixture Preparation Self-Adaption

The Lambda control system determines fuel injection duration precisely so that the fuel/air ratio is kept constant at Lambda level 1 (equals 14.7 kg air to 1 kg fuel) under all operating conditions.

Should malfunctions occur in the form of:

- Intake air teaks,
- Injector wear or carbon build-up,
- Engine wear,
- Contact resistance in mass air flow sensor,
- Defective diaphragm pressure regulator,
- Defective purge switchover valve,

the engine control module automatically corrects the fuel/air mixture by adjusting the fuel injection duration.

The degree of correction is constantly calculated and permanently stored if the following conditions are satisfied:

- Engine coolant temperature < 52 °C at start.
- Engine coolant temperature between 80 and 100 °C while driving,
- Intake air temperature between 0 and 55 °C.


Air/fuel mixture self-adaptation occurs at idle and under partial load. The maximum degree of correction towards rich or lean is 25%. After fuel injection system or engine repair work is performed, the engine control module will automatically adapt itself after approx. 10 trips. After eliminating a malfunction or after trial installation of an engine control module from another vehicle, the self-adaptation feature must be reset (see "Resetting and Reactivating ECM Memory").