Buick Repair Questions? Ask a Mechanic for Answers ASAP
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PO442 is a small evap leak, that can be caused by a defective gas cap,
a leak in the evap system, a faulty vent solenoid valve.
the evap system should be smoke tested before any parts are replaced. then if no leak is found the vent solenoid should be replaced, if leaks are found then they should be repaired.