Just some FYI for folks with a DTC31. Don't ignore it. It'* probably just a loose PRNDL switch (sits on transaxle toward back)....but if the switch is defective, it will slightly alter your idle and it puts the trans into D4 mode regardless what gear you select(other than reverse). It'll still shift normal, but can't be held in a gear....and your reverse lights/cruise control won't work properly.....so for $80 just get a new one!