My 2001 T&C LXi FWD 3.8 shows a P0456 code Small Evap Leak.

I did a visual inspection of gas cap, under air box hose, under car hoses, pulled vacuum on vent valve, looking at typical trouble spots based on internet search for similar problem. I did not find a problem.

I reset the code by disconnecting neg battery cable. The P0456 reappeared after few minutes driving.

I took it to a local shop. They came back saying I needed a new Leak Detection Pump. Said they found no leaks so they disconnected LDP did a check and determined LDP bad. Details of check not clear.

I hesitated because I thought there were two checks run by the system on the LDP itself that would have to pass before the system would run the Evap leak test and throw a P0456.

Question to you guys. Can the LDP cause a P0456? If this doesn't make sense then what would you suggest?

Thanks.