Hi,

I have a 07 Mini Cooper S. Few weeks ago,I installed a racechip box and encountered code 2885 (boost deviation plausibility error). Chip was removed but error persisted. I am having boost cuts in high gears/rpm.

First, pressure controller was changed but still having boost cuts.

I installed a GFB dv+ secondly. Boost holding felt better but code still came back. I also checked for leaks and everything seems correct.

My car is not mapped and only mod I have on the car actually is a k&n air intake.

Does anyone one have any idea? Is it the solenoid of diverter valve failing?

 

There are two pressure sensors: one in the boost tube, and one on the manifold. Both of those sensor signals are compared, and if the difference is not whats expected, you get the boost plausibility code. Either one or both of the sensors can go out and cause the code. Best to replace both of them.

Item #5 here:
https://www.realoem.com/bmw/enUS/sho...diagId=13_1206

Item #10 here:
https://www.realoem.com/bmw/enUS/sho...diagId=11_3933

 

Also check your vacuum lines between vacuum pump, vacuum reservoir, boost pressure converter and vacuum motor for the wastegate. They can fail by collapsing or softening with age. All are sold together as a single part number.

 

Get the codes read by a shop with a quality scan tool, 2885 is a companion code associated with limp mode in the turbo cars, so if there is another reason for the fault that puts you into limp mode you will also have a 2885 code.

If the fault appeared after installing a piggyback and no other work performed I might venture to say that whatever you installed caused electrical fault somewhere in the air metering department.

 

Thirdly, I swapped in a new diverter valve. Check all turbo hoses, vacuum hose (reservoir too) and two pressure sensors: one in the boost tube, and one on the manifold and everything is correct. I am still having boost cuts when i floor it. I will check the wastegate soon. I am scared that it might be the turbo but i don't have blueish smoke. I have a small play in the turbo shaft though. Can you please guide me and advise me on how to eliminate this 2885 issue?

 

Should be ZERO play in the turbo shaft. Until you get around to replacing expensive parts, try down-shifting before hard acceleration --- get the RPM's up to 3.5 - 4K before flooring it.

 

This might help-
http://jmtcperformance.com/publicati...ibility-error/

 

That is NOT correct! Even a new turbo will have readily observable play at either end of the shaft.


While it is true that loss of boost has a number of causes, one of the most likely is a leaking wastegate. Leaking is caused by a worn wastegate bushing/shaft. The only practical solution is replace the exhaust housing or the entire turbo.

 

 

Only if there are multiple causes for the fault tripping the 2885 code. It would be good practice to replace the boost controller vacuum lines as well.