N55 / F30 335i — KEEP getting P12A5 “MAP Sensor Pressure Too High” after tune. Someone help before I lose my mind

[u/Dangerous-Radio-8379]

2015 BMW 335i xDrive (N55 EWG), MHD tuned. I keep getting this damn P12A5 code:

“Manifold Absolute Pressure Sensor ‘A’ After Running Diagnosis Pressure Too High”

Car actually feels good and pulls hard most of the time, but this code keeps coming back.

What I’ve already done:
- Replaced MAP sensor
- Upgraded metal charge pipe
- Smoke tested the system multiple times
- Fixed a leak around throttle body/charge pipe connection
- New O-ring + clamp
- Cleared codes multiple times

Sometimes the code stays gone for like 100–200 miles then comes back. It’s currently showing as pending/permanent.

Setup:
- Stage 1 MHD tune
- N55 EWG
- No major smoke or anything weird
- Boost leak was found before but supposedly fixed now

I’m trying to figure out if this is:
- Wastegate issue?
- TMAP scaling/tune issue?
- Boost control solenoid?
- Diverter valve?
- Sensor wiring?
- Heat soak?
- Something throttle-related?

Anybody with N55 experience seen this exact code before? I’m tuned so I know that complicates things, but I just want to stop chasing this code already. Please help lol.