[mitchw]

Hello, new 2014 435ix owner here encountering an issue with a few codes from myself and the previous owner. Just wanted to see if I could get some opinions before I start taking parts off the car.

Current codes: (that I'm concerned about)
- 120308: Boost pressure control, plausibility: pressure too low
- 108F01: Intake air system: Suspected leak between turbocharger and intake valves

Causes drivetrain malfunction error in car (reduced power mode, no limp).

Before purchasing, the previous owner informed me of an intermittent but reproduceable over-boost code (don't have the exact code). By his description, car would code when gradually increasing throttle in cooler conditions. This also caused the car to enter a reduced power mode.

The previous owner had the car on MHD Stage 2; the car is now on the stock tune with the hopes that it would clear up the issue and delay any maintenance, but that clearly hasn't worked.

Currently trying to avoid putting the car back on the MHD tune due to cost and also concern over more burning oil than expected.

Known modifications:
- Rev 9 Muffler
- High flow catted downpipe (mfg unknown)
- AFE intake
- Metal chargepipe (mfg unknown)

I've attached a quick log I did this morning using Bimmerlink; it's not great data but it's something for now (0-60mph gradual throttle increase). Sorry for excess data, but I figured the more the better.

I'm a stranger to reading logs, but it appears that the car is exceeding the set boost target and MAF which in my head aligns more with the previous over-boost issue. It also appears that the wastegate is moving past its calibrated fully open position (if I'm interpreting correctly). Unfortunately, it does not seem like Bimmerlink has a wastegate duty cycle parameter to log for this car, so I'm pretty unsure of the EWG data as I have no base point for its positions.

The previous owner suspected that the wastegate actuator needed adjusting, recommending ISTA for a diagnosis and required adjustments.

Looking forward to any thoughts/opinions!

[thejeremyman9]

Upload the log to datazap and post a screenshot of all of the codes. The two you posted are for a boost leak

[mitchw]

Originally Posted by thejeremyman9

Upload the log to datazap and post a screenshot of all of the codes. The two you posted are for a boost leak

https://datazap.me/u/mitchw/435i-n55...1&mark=308-235

Did not know this existed, thats a wonderful tool, thank you!

The overboost code I mentioned was from the previous owner prior to sale; I am yet to record that and have only been met with the attached codes.

Will not be able to get a cleaner log for a bit, doing some travelling for the next week or so.

[thejeremyman9]

Hard to tell anything from that log TBH. Based on the codes, i would do a pressure/smoke test from the turbo forward.

[n55david]

You have a boost leak man.. between the turbo and throttle body. 100%