I took my car (1996 Honda Civic) to get it smoged, (I dont think all states need smog but my state does) and it failed the smog test, He said it was throwing up P0452 on his computer, but there was (For some reason) no CEL and there was some sort of emission leak. He told me i could take it in on Saturday but im afraid they might charge me a high price for something i might be able to fix my self. And ideas on what to check, where to start, or what to do? i appreciate the help!

 

P0452 Fuel Tank Pressure (FTP) Sensor Circuit Low Voltage

You can try a new gas cap! reset the ECU by unplugging the battery for a few mins.

Also look at the Evap sensor plug for any damage and or replace the sensor!
Buy a OBD2 scanner from harbor freight its less than $20 for the basic reader, use this to scan the ECU after and reset the monitors and codes and drive around for a few hundred miles until the systems show ready! then you should be able to pass if all goes well.

 

Ive Reset the ECU by unplugging the battery (I had to replace my battery) and i have a scanner, its not throwing up any codes, ill double check just in case though. Ill start with the gas cap and probably clean it (I heard you can clean it with WD-40) Then ill move on to the FTP sensor. where exactly is that located? as well as the evap sensor plug.

Thank you for your help and time!