My R56 Cooper S's yellow engine warning light came on , the car has suffered from reduced performance and it feels like the turbo isn't working at all. after checking the problem at the workshop this is what we got .
" 28A5 Boost-pressure sensor , plausibility ."
if i change the boost sensor , the problem will be solved ?
thanks for your replies !

 

for the last few month i had a similar experience and took it to the mini dealer, after the 120$ diagnosis they told me my turbo was probably going out and quoted 3800$ for the new one LMAO! so i took the turbo off. No shaft play, no plugged oil lines, spun freely... and the problem was the wastegate. The shaft that closes the wastgate was worn down enough that the wastegate would not seal and therefore not create the boost the ECU was expecting. filled the arm in and welded the flap to the arm so it would create a good seal. Work great! then MCS started having other issues lol, but turbo is strong again.

 

This is a great example of the issue with inexpensive components that fail when attached to expensive components.

I went thru a similar thing and the waste gate was broken. But from a dealer perspective, you are being charged for 5.5 hours of labor to get to the point where the turbo can come off the car (based on my dealer estimate). At that point it was another 2 hours labor to install a new complete turbo plus the cost of the turbo.

Once you are in that deep do you really want to continue to pay more labor to find the $200 part that failed? Wait for it to be ordered and installed etc? Or do you throw in the towel and decide that the whole unit should be replaced since it has been compromised?

Not trying to say the dealer was ripping me off. They were always great to deal with and such. I opted to handle it myself and once I took the turbo out, not only was the WG toast but the impeller shaft seals were worn which allowed oil to blow by into the intercooler and catalytic converter. After 100,000 miles that turbo was done.


As far as the OP issue, a couple of quick checks you can do is to remove the turbo inlet house coming from the airbox to the turbo. Reach in and check the impeller shaft for in/out play. There should be very little. If it is sloppy you have a problem more than likely because the shaft seals are worn.

You can also get a vacuum pump gauge for $30 or so and attach it to the bell housing of the wastegate and put the wg under vac. If it holds then your wg may be ok. If it leaks off, you have a problem there.

Lastly, I bought a cheap usb snake camera, (endoscope) from amazon and removed the O2 sensor from the top of the catalytic converter and used the camera to inspect the exhaust side of the turbo for damage including the wg. I was able to see the wg fail to close because the hinge was broken inside the turbo when using the vac pump.

In my experience the lost boost issue can be maybe 6-8 items I think. But I am not going to buy new parts like MAP sensors etc to find out that they are ok. It was cheaper to spend $50-60 on two tools and spend some time looking around myself for the root cause.

Good luck.

 

It could very well be that a boost tubes are loose. Check the connections to the intercooler and the turbo.

 

I'm having the same problem at 89,000 miles mini will not cover my warranty
my shaft is warn , is there a video or pic i can see the wast gate .Hope I'm not treading please help thanks .

 

+1 on 2x checking the air intake piping first.

I had a similar situation after my noise-maker delete solution popped off the plastic intake pipe, and the turbo boost started flowing out into the engine bay.

Hope this helps,
a

 

+1 on checking the whole intake pipe from airbox to turbo , then turbo to intercooler to the intake manifold.

N14 JCW engine.