When you say EVAP pressure sensor, I assume you mean the fuel tank pressure sensor. If you look at the first chart in the attachments, you will see this DTC is set if there is high resistance in the 5 volt reference circuit, or the signal circuit. Also, it is set if there is a signal performance issue which would be the sensor. My guess is, this sensor was fine but there is a connection issue and by the tech removing the connector and putting back on the new sensor, he re-seated it and it worked okay for a while. Again, this is just a guess based on the info provided. I would suggest scanning codes again and confirm you have the same one and then testing the circuitry.
The other possibility is replacing the sensor did not fix it and the tech was able to clear the code. Then it took a little while to reset. The actual cause could be a restriction in the EVAP canister or vent lines could prevent fuel vapor pressure from bleeding off fast enough. If the vent system cannot bleed off pressure fast enough, the re-zero procedure may not complete successfully, which could cause this code to set.
Let me know what you find after you review these documents and we can go from there. Thanks
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Wednesday, April 24th, 2019 AT 8:48 PM