If the vehicle is certified to meet California Emissions Standards, it is designed to operate on fuels that meet California specifications. See the underhood emission control label. If this fuel is not available in states adopting California emissions standards, the vehicle will operate satisfactorily on fuels meeting federal specifications, but emission control system performance might be affected. The malfunction indicator lamp could turn on and the vehicle might fail a smog-check test.
See Malfunction Indicator Lamp. If this occurs, return to your authorized dealer/retailer for diagnosis. If it is determined that the condition is caused by the type of fuel used, repairs might not be covered by the vehicle warranty.
Chevrolet Cobalt Service & Repair Manual. Motor Vehicle, Inspection
A visual inspection must always
be performed to confirm the presence of aftermarket components, potential
collision damage, or areas of concern.
1.
Inspect service history of vehicle.
2.
Inspect engine oil level.
...