[Jayphil]

Hi guys,

Since last summer I am having trouble with my car having frequent drive train malfunction errors.

First time it was related to the water pump which was changed. This improved the situation but still had some error after that. After logging I realize my car was not hitting boost (around 3-8 psi max). The error at that time was boost pressure too low...


I went to the dealer (in fully stock form) and they cleaned all sensor, changed the boost pressure valve and the diverter valve next to the turbo. After that the car was hitting boost hard but still got the drive train malfunction.

Today I did some log and the car hit 22 psi even if the car request stock boost ~10psi (JB4 map 4), WGDC show 0... The issue is not JB4 related because it was removed from the car since last summer.

My car is back to stock except JB4 map 4 for logging only.

Logs are attached.


Codes are:
120208 Boost pressure control. Upper: boost pressure too high
120408 Reduced power mode
122108 BOV plausibility - Ignore, tuner code

Any idea where to look next. Issue with the Wastegate?

Thanks in advance!

[Jayphil]

After a year all resolved now!

BMW give it a try to rechange the boost pressure converter under warranty, reset all sensor, position / adapdation etc.

The car is running perfectly in Map 0 and Map 1, boost constrol follow targets etc.

What a relief.

[OnlyGerman]

Originally Posted by Jayphil

After a year all resolved now!

BMW give it a try to rechange the boost pressure converter under warranty, reset all sensor, position / adapdation etc.

The car is running perfectly in Map 0 and Map 1, boost constrol follow targets etc.

What a relief.

Nice! Seems like just replacing it is cheap maintenance. BMW extended the warranty for that specifically.