Hi, I recently purchased a Mazda Demio Skyactiv 2016 (14,000km only) and the engine check button from day 1 was switched on. Spoke to authorised dealer who cleaned the Exhaust gas recirculation and did a reset. However, after three engine start-ups, the warning light returned back and diagnostics showed a fault PO171. Took car back to authorised dealer various times with no success. Can anyone help me by sharing maybe some experience with fault?

 

These engine are known for excessive build of carbon on & around the intake valves.

My advice is to remove the intake manifold ( relatively easy ) and visually inspect the intake valves. Also if they are driven for too long with that code they have a habit of destroying the catalytic convertor.