There are times when the Tubby Toaster doesn't work properly and goes crazy. The most well known episode where this happens is Feeding the Chickens (Also seen in Here Come the Teletubbies). Similar events happen in Washing Up (Also seen in Uh-Oh! Messes and Muddles) and Picking Chillies (Spain) (Also seen in Naughty Noo Noo!)
In the reboot, the Tubby Toaster is no longer made out of metal. It is now orange, red and yellow and curved. The pink lights in the middle have been changed to red lights and there are six lights instead of five. It also has yellow lights going around the sides. It does have button to turn it on, but the Teletubbies are never seen pressing it.