Upshifts To O/D From 3RD While Engine Is Cold

Check O/D switch and O/D OFF indicator light circuit. See O/D SWITCH, O/D OFF INDICATOR LIGHT CIRCUIT chart in TESTS W/CODES article.
Check water temperature sensor. See CODE 22 in TESTS W/CODES article.
Check transmission for mechanical failure.
Check ECU. See SYSTEM/COMP TESTS article.