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These codes are directly related. The P1457 sees a "leak" in the EVAP system, while P0453 is pointing to the Fuel Tank Pressure Sensor. So, more than likely, the FTP Sensor IS the source of said "leak". Carefully inspect the vacuum lines to the FTP sensor for any cracks, holes or loose/missing connections. If the visual inspection checks ok, replace the FTP, making sure it seats correctly and tightly. Best access to the FTP is from under the vehicle, driver's side, towards the rear:
Yes, the cube just above the solenoid. Should just "pull" off. Unfortunately, no Honda testing procedure provided. That I know of, yes, Dealer item, however, NAPA has been getting in more EVAP related parts lately, can't hurt to call and ask.
Yep! Sounds like that is going to be the problem! I bet that harness is what controls the FTP sensor. I bet when the harness is repaired, so will the 2 codes!