Have replaced fuses, changed battery, swapped access 4 and access 3 with another truck, tightened all related connections, checked for shorts to frame. Checked for continuity in harness for ed contactor, installed new ed contactor. Truck operates perfectly when first keyed on, but when operator steps off of truck long enough for contactor to drop out then steps back on that it throws code. The contactor pulls in for just a second then drops and codes 345. Battery voltage seems to be good on power cables not the 2.5volt difference that is supposed to trigger code. It doesn't do it every time but probably 1 out of 4. In this warehouse operators constantly on and off of truck so rekeying every time is a nuisance. Any ideas.