I bought this Mini about a month ago and it ran ok but now it has a bad miss and check engine light came on. I changed the oil then added new plugs, coils, exhaust, gas cap and cold air intake and now it is throwing 2 codes and running like crap. I went back and checked my work on everything to make sure everything was plugged back in but nothing was out of place. My scanner is throwing codes A0B2 and A0B5 and I can't see to find out anything about it. I also noticed that the fuse holder that comes off the 2nd battery cable does not have a fuse in it. Any help would be appreciated.

 

A0B2 has to do with power to the Control module Access, it reads the chip in the car's key, your car shouldn't start with this code.
A0B5 is the code for a bad ultrasonic sensor for parking distance control, I don't think that would apply to a MINI.
What do you mean by a fuse holder in the "second battery cable"? Maybe you mean the Intelligent Battery Sensor box on the negative battery cable, it monitors the battery and is the reason that you have to register a new battery.

 

It does start just runs really bad. How do I fix that? Does the battery in the key need to be changed? There is a second cable coming off the positive terminal with a screw type fuse holder that has nothing in it. I looked a couple videos on replacing the battery, which I did, and I see the extra cable connected but don't see my style of fuse holder.

 

If it cranks, it's not the key.

Check your connections that you undid,when you changed all the stuff out. Something may not be plugged in all the way.

 

I have been over and over the connections that I took apart but can't find anything unlooked or not hooked up correctly. Does the A0B2 code narrow things down for me to look at something specific?

 

No, the A0B2 code has to do with the power connection to the control unit for the key interlock. it the car starts, there is nothing wrong with it.

It could be the High Pressure Fuel Pump, or dirty injectors, or a clogged fuel filter. It may not be an electrical issue at all.