1.9 TDI 2V / 2.0 TDI 2V Exhaust Emission Warning Light P0101 16485 G70 (Solution)

Problem:
Check engine light is on. Event log entry: P0101 16485, Mass airflow sensor (G70), implausible signal. Additionally, a lack of acceleration may occur up to approximately 2200 RPM.
Reports have also surfaced regarding the addition of Diesel Particulate Filters (DPFs) later on.

Cause:
The oil filler cap has fallen off the pivot lever shaft. Due to the resulting oil loss, the oil pressure in the cylinder head decreases, causing the valves to only open partially.

Solution:
Remove the cylinder head cover and check if the aluminum plugs are present on both sides of each rocker arm shaft. If one or more plugs are missing, remove them from the cylinder head. Always replace both rocker arm shafts.