Limp mode/charge pressure

[Iftekar]

This is driving me crazy. Every time I floor it on higher gears, engine malfunction light comes up and engine goes to limp mode.
To be specific this happens when I am on 5th or 6th gear and I floor it. Then if I restart the car, everything comes back as normal. Engine starts fine. When it goes to limp mode, I don't hear any noise at all.

Car is 2011 335i E93 6spd. Miles =93k.

So far these things were checked/done

-dealer replaced air flow sensor under warranty
- charge pipes replaced under warranty
- hpfp replaced 2 yrs ago
- spark plugs and coils replaced 8 months ago
-no codes for misfire or hpfp
- intake valve cleaning performeda year ago

If I floor it on any other gear (1/2/3 etc) it pulls up just fine. Only happens when I am on 5th or 6th. (Speed around 70mph)

Onlything I haven't done yet is to clean/inspect the vanos valves. I tried to take them out but for some reason on this N55, they aren't easy to get out. I saw plenty of videos but they are based in N54. Not sure if anything changed on N55 but I couldn't take them out. They are so so stuck that I couldn't pull them out.

Codes(Every time the same code)

Charge pressure control, plausibility: Pressure too high
Code: 002C56
Charge pressure control, shutdown: pressure build-locked
Code: 002C58

Any pointers/suggestions will be greatly appreciated.

Thanks.

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[White94RX]

My first guess would be the pressure converter. This is the black box on the right side of the engine with the vacuum lines going to it. One from the valve cover (vacuum source), and one going to the wastegate actuator. This is what opens the wastegate when the boost hits a certain psi.

[Iftekar]

My first guess would be the pressure converter. This is the black box on the right side of the engine with the vacuum lines going to it. One from the valve cover (vacuum source), and one going to the wastegate actuator. This is what opens the wastegate when the boost hits a certain psi.

Oh I forgot to mention. Pressure converter was also replaced by dealer under warranty.

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[White94RX]

Start by measuring how much vacuum is coming off the nipple of the valve cover going to the converter. Then use a vacuum pump to put 20+ vacuum to the wastegate actuator and see how much it moves and if it moves properly.

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[Iftekar]

I was just going through my repair notes.
I see that they had also replaced pressure sensor. But the part number mentioned is confusing me.
13627585493
When I looked up onlone-this part number is for N54 engines and N55 has a different one. Will that make any difference ?

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[Iftekar]

My first guess would be the pressure converter. This is the black box on the right side of the engine with the vacuum lines going to it. One from the valve cover (vacuum source), and one going to the wastegate actuator. This is what opens the wastegate when the boost hits a certain psi.

I misunderstood this one. I rechecked the repair paper and it was actually " pressure sensor" they had mentioned - MAP sensor.
I ordered one from ECS tuning and should arrive by this weekend. Let's see.
Also I noticed, oil leaking from my oil pressure sensor and the connector is fully oiled. I ordered that part also but just wondering if I should clean the connector with the brake cleaner fluid may be ?

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[Iftekar]

I replaced the pressure converter or waste Gate actuator valve. Was real easy job.
I noticed some difference while WOT- it seems to pull hard. No problems in any gear till 5000 rpm. I think this will work but I will do more tests to confirm.

Thanks for pointing me to the right direction.

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[White94RX]

No problem. Good luck.