P0455 large leak detected

Question

P0455 OBD code shows large emission leak. I have replaced the first possible part, the gas cap. Light was reset and a few weeks later the light came back again. I scanned the car and the same code shows the same issue, large emission leak detected. I'm afraid in taking it to the dealer and be charged an arm and a leg to fix.
Can you help me find a solution.

Answer 1

P0455 Evaporative control system Large leak detected

There a TSB that Mazda has produced that may just apply to your situation, TSB # 01-019/12. This is for the FTP (Fuel tank pressure) sensor, If the FTP reports the incorrect fuel tank pressure/vacuum you would set a P0455.