Patent ID: 8862316

Claim:
A method for diagnosing the operational state of a motor vehicle internal combustion engine fuel supply system, said fuel being stored in a tank of the vehicle and containing a variable alcohol content, the method comprising: initializing diagnostic parameters, including setting an alcohol content detection parameter at a first value to indicate that the alcohol content of the fuel has not been determined; detecting an addition of fuel to the tank; determining the alcohol content of the fuel; after the determining the alcohol content of the fuel, updating the alcohol content detection parameter to a second value to indicate that the alcohol content has been determined; checking whether the alcohol content detection parameter has been updated to the second value to indicate that the alcohol content has been determined, including authorizing the diagnosing of the operational state of the fuel supply system after the checking determines that the alcohol content has been determined; calibrating the diagnostics parameters based on the alcohol content determined by the determining; and initiating the diagnosing of the operational state of the fuel supply system using the calibrated diagnostics parameters.