Hello all. Just got this code on Saturday. Fuel cap looks good. What should be my next steps to find the culprit? 2019 Scat Thx
Not sure what a P0456 code is but if it does relate to the gas cap I wouldn't go by looks. Get a new OEM to rule out the problem or solve it.
The Powertrain Control Module (PCM) at different times performs various tests on the EVAP system. OBD II Enhanced EVAP systems are in place to keep fuel tank vapors from venting into the atmosphere and, instead, purges them into the engine to be burned. Regular pressure tests are conducted by the PCM to monitor the sealed system for leaks. The PCM monitors the EVAP system pressure by watching the fuel tank pressure (FTP) sensor. When the sensor indicates a small leak in the EVAP system, this code is set. There will likely be no noticeable symptoms other than the Malfunction Indicator Lamp (MIL). This is because the EVAP system is a closed system and only controls fuel tank vapors, not engine management. I once encountered this code on my 2009 SRT because of a defective (new) Stant locking gas cap. When I put my OEM cap back on, the code disappeared. So, I would try a new gas cap first, as the easiest solution. If that is not the problem., you will need a scan tool to determine the cause. Using this tool, you must activate the vent solenoid, sealing the system. Then you must monitor the fuel tank pressure (FTP) sensor. If the system is sealing properly, the number will stay consistent. If it isn't, the pressure sensor will show that. If the system slowly leaks, use a smoke machine and watch for smoke exiting the system at any EVAP component. Anywhere there is smoke exiting the system, that is the faulty component. Do not pressurize the EVAP system with air pressure. Doing so can damage the purge and vent solenoids.
