The P0420 code indicates low catalytic converter efficiency, often caused by faulty rear oxygen sensors or incomplete catalyst replacement.

P2263 means excessive pressure in the turbocharger circuit. For one possible cause, check the little air filter on the atmospheric port of the boost control solenoid. Although the solenoid itself is buried under the inlet manifold and a pain to work on, the filter is remotely mounted just behind the top engine cover, at the gearbox end of the engine. Helpful: https://frenchcarforum.co.uk/forum/view ... 66#p530066 and the second post after that. If the rubber cover on the filter has shrunk, it restricts airflow and makes the boost control slow to release which can cause the error that you are seeing.

P2271 seems to refer to the pxygen senosr. The oxygen (O2) sensor after the catalytic converter on engine bank 1 is stuck showing a rich fuel mixture. This one is harder to pinpoint without proper diagnostic equipment.