Q: Engine Code P0016

The P0016 code is most likely due to the engine sludge build up as the VVT (variable valve timing) system is control with oil pressure. In regards to the engine flush, I whole heartedly agree with Toyota. The number of possible passages to clean and remove sludge from is scary. Once you begin to dislodge the oil sludge from the engine, it will simply move to another location. It is almost impossible to clean a motor internally in this fashion without clogging another artery.

With that said, it could be worth the effort, although I recommend doing in yourself and giving yourself a lot of time. Be as patient as you can. The biggest challenge will be removing the sludge that you hope will eventually make it to the oil pan. It can get stuck in the pan and clog the oil pickup screen. When this happens, you must remove the sludge to run the motor or the motor will be starved of oil and internally damaged. In addition to removing sludge from the oil pan, you will need to remove parts of the VVT system that has oil screens. They tend to clog over time with good maintenance. In this case, as you free the sludge inside the motor, it will clog those screens very quickly.

It can be done, but it often requires the removal of the oil pan on multiple occasions as well as every part that has a screen. If you have the money, it is much much simpler to simply replace the motor.

Good luck!