hmmmm......... I scraped this off the Internet ..........( which makes it FACT ....
)
However, it sounds about right to me.
"Nothing new, all of Toyota's D4D engines have this. The "self cleaning" is simply the engine switching between direct and port injection depending on what's optimal? As a side affect by going into the port injection system it helps clean some of the excess carbon build up left by the direct injection."
humfrz