I know there are plenty of problems associated with this code, but all the symptoms lead to either replacing the Bypass Valve or the throttle body or even the harmonic stabilizer.

Basically my car has the same effect of the code. The car suddenly goes into limp mode, not going above 2k rpm and it also starts starts to shake. It's as if there are only 2 cylinders firing instead of all 4. The check engine light comes on, along with the EML and traction light as well. Restarting the car fixes the limp problem up until it occurs again.

After a couple cycles, the CEL would turn off and the car would drive but it would have very little boost. So little that I could barely hear the supercharge whine up until 5k rpm, and it would have a very consistent low whine as well. It's as if theres a very small amount of boost being fed into the SC. Could this still be the result of a bad Bypass valve?

The CEL code I have comes up with this description pointing to some pressure sensors. Maybe this can point me in the right direction.




I noticed the problem would occur when I had a lot of electronics on at once. Not sure if that's just a coincidence or if its a random occurrence.

When all the symptoms were pointing to the BPV, I decided to start there first. But upon inspection, I was bummed to see that the BPV was in good standing condition so now I have to dwell deeper into the issue. The spring seems to be giving enough resistance and the valve is closing all the way.



Maybe irrelevant, but there's another tube that goes along into the intake. If not, then it must've been the previous owners doing. Not sure what the point of that is..

 

Most the time when you get this code and it goes into limp mode it is the crank pulley failing. Sometimes you can even smell burning rubber if it's real bad. We just replace it with the ATI damper
https://www.waymotorworks.com/super-...ulley-r53.html

The extra vacuum line coming off your bypass valve is for the JCW intake. Often we just remove it and remove the flap from the box as they slide off all the time.

 

How many miles on the car? On the crank pulley; 1.) Need to pull the passenger side tire. 2.) Use a jack stand to support the car. 3.) Take the pressure off the belt 4.) If the crank pulley/harmonic dampener is going, you should be able to push the pulley in so that the inner portion hits the motor, or, there is rubber residue around the pulley. If the crank pulley is slipping the supercharger will hiccup and the lack of pressure usually throws the code.

You may also have a bad leak around the BPV. I have found the euro style clamps, there are two at the BPV, to allow a good flow. You should also check the throttle body. Remove the plug on the driver side, check to make sure the pins are not bent. When you put back in, use some dielectric grease. You should also spray some carburetor cleaner on the round throttle key (remove the body and put a rag under so the cleaner does not run down in the black plastic supercharger duct.

Last but not least, you should check that black sc duct as well. The easiest way is to pressure test the system. You can buy them on line or make your own with a 2 1/2" PVC cap, a water pump type pressure gauge and a tire valve. If you do, be sure to have good clamps where the air box tube mates to the throttle body.

 

The mini is at 64k miles and its an 06. I thought the crank pulley was redesigned on the 05-06 mini's? Is there a way I can tell that it's the crank pulley? I was just about to buy a new BPV, but then again the code's description points to MAP sensor 2 at high voltage.

Could it be just the MAP sensor not showing correctly?

64k miles on it. I didn't notice any signs of leakage around when I removed the BPV. I'll put some carb cleaner on the TB because there was a bit of dirt on flippy switch thing.

 

Yes they changed the crank pulley design on the 05-06 cars. Which is actually worse as they are more prone to failure than the earlier ones. That is why I suggest it first.
Don't buy a BPV as that is not likely it we've very rarely if ever see them fail. The internet makes it out to be they all fail, but that's just not the real case.
It is possible for the MAP sensor to be bad, but no way to tell without testing it out.

 

What would essentially be easier to fix, sensor or the harmonic balancer? Maybe this'll help diagnose the symptoms.

When I'm accelerating hard, sometimes my exhaust would give out multiple popping sounds, it's the same sound that happens when I let off the gas pedal. Could this somehow be of any help to figuring out what the issue is before I start splurging out my cash?

 

Sounds like you are working with only half of the puzzle. Would assume that with a Bentley Manual, mine is on order, you could do some tests on the MAP to see if it is the problem. As I stated in a past post, the crank pulley comes into the picture if it is really going as when it slips, the supercharger hiccup causes the code.

Without the Bentley, and if you have also checked the others items I previously noted, I would replace the MAP. If this did not work and the pulley looks/sounds ok, I bite the bullet and take the car to a shop. I would not chance spending $200-$400 on a pulley and then have the issue still occur.