That code should clear with the batter disconnected. If it came back on then you still have a problem. EVAP codes can be a major pain. You could have a damaged O ring, or other leak in the system. Check the gas cap, check all the vacuum lines from the tank to the engine. The canister could be clogged. Your test of the purge valve will be fine. All you did was go threw it'* motions. The valve is either open, or closed. And you had it do both. You also test the harness and confirmed voltage. So that'* all good. So move on to the next area. Your lines.
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1997,1998,2000,2005 year confused Bonneville SSExi. Stock? ish.
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