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Some of the 2016 4 Cyl engines did have to have the front 02 sensor replace. An air intake leak after the AMM will also set a P0171 and/or 02 code. Inside the red circle is a one way check valve. Hose 4 or 5 goes from the oil trap 1 to this one way check valve. This is how engine oil vapors get re-burnt back into the engine. This one way check valve will become coated with oil vapor gunk and not seal at idle. This can set the code. #1 PCV box valve will fail and set the same code(s). If the engine S/N label is on the top of your pcv box, it is original. Pcv box 1 has a high failure rate.
You need to replace #14 pipe to get the check valve. Hose 4 or 5 will crack where it goes into the check valve. The above is the same for a supercharger engine. You may end up replacing all 4 parts, 02 sensor, #1, #14, #4 or #5 to keep the light off. Also, you need to go into VIDA, ECM adaptations and reset the adaptation values. A battery cable reset should be done also, this will erase the stored short term memory. The only way to test the one way check valve is smoke test thru hose 11 and see if smoke exits out thru the one way valve. You can remove the hose at the check valve. If you see dirty oil gunk on the one way valve, replace fresh air pipe #14. Do not use these part #'s to order parts for you car. Let the dealer order parts using your VIN.

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