Dubuc

Evap
I have a 2000 Cherokee with a evap problem I've been trying to chase down for a while I've changed the gas cap and some hoses had a smoke test done and the shop said evening was ok up to the purge valve but I've replaced that awhile ago thay said that thay could not test the return side of the line so I tested the purge valve with my battery and it is still working then I tested the plug for The purge valve and it had voltage on both sides positive and negative on the positive side it was 11.4 volts and on the negative side it was 4.2 volts wen I tested it I had the multimeter grounded on the negative battery terminal I don't know if that is normal if anyone can help it would be much appreciated