Hi all,
I am totally new to Minis, and just got my 2009 MCS. It has 77K mile on it.

When I went to test drive the car, it was pleasant to drive. Picked it up the next day, and after few miles, the half shaded engine light came on, and I felt the car does not accelerate as it did the day before. The oil it had was very bad, so I changed it, bit things did not really improve much. Well, the light comes on and off, but stays on most of the time. When it is off, the car drives fine. No CEL at all. I used my scanner, and went to Autozone, and codes registered.

I got a gadget that displays sensors. The boost pressure ranges between -11 and +2.8 PSI. It pretty much never go beyond 2.8 PSI. That is the case whether the Limp mode light is on or off.

I asked the previous owner, who is an old gentleman, and he said pretty much the only thing it needs is a new oil. Also, he just replaced the theromstat housing few days before the sale.

I searched, and I see suggestions to check: boost solinoid, vvt solinoid, diverter valve, MAP/MAF sensor, vacum/boost hoses, ...

Kindly, I would appreciate and suggestions on where to start based on my description.

Many thanks.

 

Check the hose connection on the passenger side of the car at the intercooler and work way back to throttle body. If everything is good then it’s most likely the diverter valve on the turbo.

 

Thanks.

Looked at the lines, and could not tell if they are bad or not.
Opened the diverter valve, and it does not seem to be bad. The outer gasket (o-ring) seems dry a bit, though.

Putting an order for a new diverter valve. Will see if that solves the issue. Will report back next week.