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Home >> Pontiac >> 2007 >> Grand Prix Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls & Fuel - 3.8L - DTC P0341 To P0507 >> DTC P0420 >> Repair Procedures

Repair Procedures

IMPORTANT: A new converter with less than 100 miles on it may set DTC P0420 due to out-gassing of the internal matting. Operating the vehicle at highway speeds for approximately 1 hour may correct the condition.