[khadzok]

Hi Everyone,

I have a 2011 535i with ~110k running MHD stage 1
Started the car one morning on a damp rainy day after it's been sitting for about a week. It started fine but I could feel minor vibrations at idle which cleared out once engine reached operating temps. After about a half hour drive, stopped and parked it for the next 4 hours. On the way back home, while cruising around 40mph, CEL started to blink, and cluster got stuck at 1000rpm, speedometer was still working, no other changes in the way car drove.

I pulled over, read the codes with generic obd reader which showed nothing.
Then remembered I had the wireless mhd adapter with me. Read the codes again and got these 4:
120208 Charge pressure too high
120308 Charge pressure too low
120408 charge pressure control switch-off
213301 power management: central over voltage

Cleared the codes in MHD app, restarted the car. CEL started to blink immediately, but again there were no codes per mhd, yet RPM needle was showing a constant 1000 no matter the engine speed.
Unlocked cluster, it also reads exactly 1000rpms at all times.

While CEL was still flashing, I just took the car on highway and drove home and parked.
About an hour later, googling for these symptoms, went back and restarted the car. No CEL, no funny running, and no codes stored, RPM works fine.

By the way, couples weeks ago I changed boost control solenoid, and all related drivability issues, which is not the topic of this thread got resolved, but I never cleared the codes, so those 120xxx codes might just be old stuff.

Any ideas what might have happened?

[95blkmax]

you have MHD, did this happen while you were cycling the BC button on your turn signal stock?

MHD has a feature of map switching that you hold down the BC button to select which you want to run- regardless of you having multiple maps flashed or not. The way it lets you know you are in this "map selection mode" is that the RPMs drop to 1000 and hold, and the CEL blinks". Just hold down the BC again and it goes back to normal.

As for the codes, they could have been there from prior and just never cleared

[95blkmax]

to clarify- the BC button still functions as normal. Normal Click makes the info on the gauge cluster cycle. Long click is how you access this MHD feature. And it will stay there until you long click it again.

[khadzok]

Thank you so much. That must be it.
I now remember resetting consumption on cluster, which involved holding BC approximately 2 seconds.

I feel so dumb yet so relived and happy at the same time.