Fiat FIORINO Owner's Handbook Manual page 40

WARNING
5) Regardless of the last fuel system used,
at the following engine starting, after the
initial petrol stage, the system will
automatically switch to methane.
6) At the time of the switching request
there will be a metallic noise from the
valves which are pressurising the circuit
(more obvious with the ignition key in
the MAR-ON position). For the switching
logic described above, a delay between the
valve ticking and the switching off of the
instrument panel indication is completely
normal.
7) Do not switch between the two
operating modes whilst starting the engine.
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