2001 E320 4matic not upshifting

[RollinK2]

Help! It's a 2001 E320 4matic, 62,000 miles. Several times today the car would not upshift out of 1st gear when in drive, when leaving from a standing start. Also the selector indicator on the dash says 4, not D when this happens. It also wont manually shift when it's stuck in 1st. The only way to reset and get it back into D is to shut the car off, then try again. Now the check engine light is on, but no codes in the dash display. Any ideas where to start on this, is there a shift position sensor telling the ECU that trans is in 4th gear when it's really in first? It's also making VERY hard upshifts from time to time over the last week or so. Thanks Rollin