2007 MCS JCW lost power
 

I have an 07 MCS with dealer installed JCW pckg with 56,000 miles. My problem is i have the power reduction light coming on. this only comes on when I'm under hard acceleration or punch it in lower rpms. first thought was bad gas so i Seafoamed a tank of 93oct gas and it seemed to help, light was not coming on as soon or as long. Well that still does not satisfy me so i bought the ALTA A/P and read my codes. Im getting a the P28AA (bypass valve error) I have spent the last week searching for this and can not seem to find any info on it. Can somebody tell me what might cause this? The only way to clear the light is to shut car off or clear the code with the A/P.

Would love to help you, but according to my Bentley service manual for the MINI, that P28AA isn't even a valid fault code.
Grab hold of a Bavarian Technic or another approved MINI-protocol scanner to see what turns up.
Reply back with any / all fault codes that are stored in memory.

- Erik

Your DV might be going bad. Not under heard of.

Attachment 162559
After getting the intake cleaned with BG44, I had great boost for about 15 miles of lead footing then I got the CEL and p2885 code. I thought I might have a turbo failure of the wastegate so I checked around for turbos. I also did some troubleshooting of the wastegate and vacuum lines. I put a vacuum hose from the cam operated vacuum pump straight to the wastegate. I got some boost but not enough to satisfy the ECU/MAP. It had to be either a leak on the intake hoses or the diverter valve failed. I made sure there was no leaks on the intake hoses by using homemade plugs and gauges to put some pressure (10 psi) to the hoses before the intake manifold. The diverter valve became the prime suspect but I would not take it off before having a new one on hand. This item is plastic and could break or fall apart when being removed from the turbo housing. I ordered and received a new one from Way Motor Works. Problem solved. JM Turbo Coopers is an excellent source for info and parts also.

I think it's fair to say that I was correct in diagnosing the issue. I must add that I removed the hoses from the turbo and checked the compressor turbines for free operation. I checked the wastegate for proper actuation and closure before making my conclusions on the diverter valve.

The real odd thing is the code. Its P28AA which I have searched high and low and cant seem to find anyone who has posted anything about it anywhere. It does read bypass valve error which leads me to believe its my whole problem just wanted to see if anyone had this problem. I'm new to the whole MINI scene so i apologize for the newbie questions. Where is the valve located? I do appreciate any and all replies!

There's just a handful of archived posts that you'll want to read up on:
* https://www.northamericanmotoring.co...-about-it.html
* https://www.northamericanmotoring.co...g-upgrade.html
* https://www.northamericanmotoring.co...with-pics.html
* https://www.northamericanmotoring.co...ter-valve.html
* https://www.northamericanmotoring.co...hread-105.html

The diverter valve (DV) is mounted on the compressor side of the turbocharger.

- Erik

Well after replacing my bypass valve with the forge unit I am getting alot more boost but the light is still coming on and throwing the P28AA code (bypass valve error) I made sure all connections were tight and no leaks. The car runs at normal temp and not getting hot. I'm starting to run out of ideas.

Might be over boosting with the Accessport. Data log the car and send it into Alta and have them correct the tune for you.

I Have had this problem since before the A/P. Actually the only reason I bought the A/P was to read the codes. I haven't installed a tune yet.

Hmmm sounds like a mechanic is in order to see what is really going on.

Nearest dealers is an hour away i just cant afford to take a day off work for that. People seem very helpful here so I'm hoping between all of us we can figure something out. Thanks for the reply's though guys!

Have you checked all the electrical connectors? Plus where are you?

I'm in Northwest Ohio. During the installation of the Forge valve I rechecked all connections and all hose clamps, everything seemed tight.

Next is to have someone with an approved MINI-protocol scanner (like a Bavarian Technic) to make a visit...
Reason being? You'll be able to pull direct MINI faults and be able to data-log critical values like duty cycle of the DV and other components.

In the mean time, complete a full inspection and pressure test of the vacuum tubing system AND a pressure test on the intake tract (boost pipes, intake manifold).

- Erik

How close to Detroit? You could go see Chad.

Boost/fuel cut will not throw codes fyi.

Well I figured it out! After some frustration of not clearing the problem with the new BV. I searched all night and found a picture of a bad stock BV, and noticed a ring that I did not see on mine when I took mine out. So I tore the Forge unit back off today and sure enough the plastic ring from the stock BV was still in the turbo. Pulled it out and BAM! No more light and no more power cuts. Big thanks for all the reply's though!