[sowbmw]

Can anyone please provide some insights?

I have several codes that have come up and the occasional check engine light during WOT.

Codes: 29D0,29D2,2BC1,2774,28A0

The car drives fine at low speeds. On the highway (>100km/h(60mph)) the car drives fine however when I gently tap on the accelerator, I would hear the turbo spool up (highly audible) then "blow off". Car also lack power when the check engine light is on.

In the past I replaced the boost solenoid with a pierburg unit from fcp euro.

I've cleaned the MAF and TMAP. All ignition coils have been replaced.

I just performed a smoke test and there was a minor leak at the lower bung of the vrsf charge pipe, tightened it up and no luck.

I need to replace the vacuum hose from the boost solenoid to the waste gate actuator, but don't see any visible cracks. Will also perform the sib that says disconnect purge valve and let car run for 15 min.

When I clear codes, car drives fine (has power as well).

Any help would be much appreciated.

[TunafishE93]

The first two codes are directly related to the intake temperature sensor and two following could be collateral damage from the first two codes. You can log your air intake temperature to see if you are getting any funny readings when you go into fault.
The air intake temperature (TMAP) sensor is on the charge pipe.

[sowbmw]

I cleared the codes and then tried to replicate the check engine light, but it did not come on.

However, the first two codes are gone, and these are the codes that remain: 28A0, 2774, 2BC1

My code reader says that:
28A0 - Throttle valve opening angle-intake pipe absolute pressure, comp arison Pressure too high
2774 - Air mass, plausibility: Air mass too high
2BC1- Mixture control: Fuel-air mixture too rich

Is it possible there could be a crack in the intercooler pipes/turbo inlet that wouldn't be detected by a smoke test?

Also I replaced the boost solenoid about 4 years ago. Could it have gone bad? It seems kinda bizarre it would go bad so quickly.

[TunafishE93]

So all the codes, even before has the TMAP sensor in common. I would trace wires, maybe even get a new sensor.
Attached is the N55 error code cheat sheet. It gives some troubleshooting hints. You will also notice that some of the BMW codes have multiple meaning, this is where the P codes are actually more relevant than the BMW codes.

[sowbmw]

I pulled some values from a free app called Car Scanner ELM OBD2. I will go through the tmap sensor wiring today.

I've attached pics of the readings. Hope they're readable (Sorry for the large photos, will try to resize them)

[sowbmw]

Did another smoke test and visually inspected pipes again. Doesn't seem like there are leaks.

I can drive the car at 2k rpm or less and the check engine light won't be triggered (code 28a0 still present). When I drive hard, stop the car, then turn it on the next day, a check engine light comes up.

I will order a new map sensor. Should I order both (charge pipe and intake manifold)?

[sowbmw]

I’m thinking a boost leak or failed boost solenoid. I vacuum tested the system, but I’ve read that may not be enough. I replaced the boost solenoid 4 years ago with a pierburg unit so I’m having a hard time accepting that it would fail after 5 years ( 2 of which the car was running)