Persistent P0401 code after cleaning

2011 3rd gen 600,000kms

Cleaned the entire egr system, intake channels, valve, cooler, etc, also replaced intake manifold gasket. Intake was so clogged there was 0 flow in 1&2.

no code before cleaning

now have a P0401 that appears after about 70kms of driving. If i clear it, it comes back after 60-70kms or so. (At least the engine runs smoother and better eco)

Also, not sure if I’m hallucinating this yet but i think i can hear engine knock (pre det pinging) once the check engine light appears. Then it goes away when i clear it. Not sure if the ecu makes any adjustments only once the light is on.

To try:
replace gaskets on pipe between egr valve and intake.
Clean mafs

Any other things to try?

 

looks like it could the the ‘ski jump’ on the egr magnet. It looks quite worn tbh

 

MAYBE FIXED

90kms after replacing the egr magnet (slope on new magnet is worn but it still stop the magnet from turning)

no more p0401
Fuel economy is now 4.1L/100 (57mpg)
Up from 5-5.3 (engine must have been running rich?)

hopefully its fixed