Ethanol-Related Fuel Control (Only Applies To Version FLEXIFUEL)

The vehicle can be driven on anything from pure gasoline to pure E85. E85 of summer quality consists to 85% of ethanol, winter quality consists of approx. 75%. The remaining share is 95 octane gasoline.

Gasoline and E85 have different characteristics regarding energy content, among other things.

The Engine control module (ECM) must adapt the combustion to the fuel's different characteristics through ethanol adaptation.

In order to determine the amount of ethanol a number of checks must be carried out by the Engine control module (ECM) :

• The whole procedure starts by checking if the tank cover has been opened with press of a button, and the actual fuel level is compared with earlier driving cycle.
• Opening the tank cover by pressing the button always results in ethanol adaptation. If the vehicle is filled, but the cover is not opened by pushing the button, ethanol adaptation starts if the change in fuel level exceeds a specific value.
• The vehicle has been stationary long enough for the fuel level to have had time to stabilize.
• The control module checks that the amount of fuel filled is sufficient in volume.

Before the Engine control module (ECM) starts calculating, a number of other conditions must be met.

• The engine temperature must exceed a specific value.
• Fuel trim must be active.

Based on the current fuel consumption (after filling) it's registered while running that the "old" fuel has disappeared from the fuel lines, Adaptations are not completed until a sufficient amount of the "new" fuel has been combusted by the engine (minimum approx. 0.8 liters).

You should also consider: 

• Diagnostic trouble codes on the mass air flow sensor, catalyst monitor sensor and/or fuel adaptations can prevent/impair the adaptations.
• Aim for even acceleration.

First when ethanol adaptation is complete will the normal fuel adaptation start.

For example, if there should be diagnostic trouble codes, or other factors that prevent engine control module (ECM) from starting the calculation, the earlier adapted ethanol content will apply until the ethanol adaptation is allowed to run again.

It is possible to read the current calculated ethanol content via DIAGNOSTICS/VEHICLE COMMUNICATION/Advanced in VIDA.

The actual ethanol content in the fuel can be determined through a special measurement method, or can be known in another way, for example, through the vehicle being consequently filled with a specific fuel composition.

Under DIAGNOSTICS/VEHICLE COMMUNICATION/Advanced it is also possible to program the desired ethanol content, so that the following fuel adaptations can be calculated based on this value. It should be noted that when the tank hatch is opened by pressing the button, a flag is set in the Central electronic module (CEM). This does not disappear until after a certain operating schedule. There is therefore a risk, if the tank hatch has just been opened, that the vehicle will start calculating the ethanol content itself, and the newly programmed value comes to nothing.

For other information, see applicable Diagnostic trouble code information for each diagnostic trouble code information under DIAGNOSTICS/VEHICLE COMMUNICATION/Advanced.