A code p0455 most likely means one or more of the following has happened:
-A loose or improperly affixed gas cap
-A non-conforming gas cap (i.e. not factory/original brand)
-Other leak or damaged piece in EVAP system
With a p0455, the most common repair is to:
-Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
-Otherwise, replace the gas cap, and/or
-Inspect the EVAP system for cuts/holes in tubes/hoses (you may hear a vacuum noise or smell fuel), repair if necessary
As for P0201, the causes could be any of the following:
-Bad injector. This is usually the cause of this code but doesn't rule out the possibility of one of the other causes
-Open in the wiring to the injector
-Short in the wiring to the injector
- First, using a DVOM check the resistance of the injector. If it isn't within specs, then replace the injector.
- Check for voltage at the fuel injector connector. It should have 10 volts or more.
- Visually check the connector for damage or broken wires.
- Visually check the injector for damage.
- If you have access to an injector tester, activate the injector and see if it operates. If the injector operates, then you likely have either an open in the wiring, or a blocked injector. If you do not have access to a tester, swap the injector with another one and see if the code changes. If the code changes, then change the injector.
- At the PCM, remove the driver wire from the PCM connector and Ground the wire. (Make sure you have the correct wire. If you're not sure, do not attempt) The injector should activate
- Replace the injector