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How much should I expect to pay to replace the ...The following codes: p0171 and p0131
How to diagnose and repair a p0441 obdll code t...The check engine light does stay on it throws the same code every time but goes off and on
Asking this for a friend. Their mechanic says the fuel tank ventilation valve is broken.
What is the fuel tank ventilation valve?
What does it do?
Is it an important part? If yes, Why?
EDIT: In general, could they replace it themselves? Would it be a difficult job?