Hi mate. this may be worth a look (thanks to devon aygo a man in the know) There is a TSB ( technical service bulletin ) from Toyota ref # EG-0004T-0110-EN which describes: (note the bulletin only relates too T180 2.2 diesel Rav4, Verso, Avensis & Auris with Diesel particulate filters ) "DESCRIPTION OF PHENOMENON Some customers may explain about intermittent white smoke from the exhaust" There is a specific set of checks which need to carried out, checking the correct operation of: If a DT