Yesterday I just pulled 2 codes they were -
p1242 - Secondary upstream manifold air pressure sensor too high in deceleration
p1238 - Secondary upstream manifold air pressure sensor high input

I know these are over boost codes but how the heck am I throwing codes with a 17% pulley and a JCW head!?

Day Conditions when i got the code - 40f cold

Could someone tell me what's going on?
What should I do?
Get a higher flowing head?

 

Make3 sure the boost control valve is functioning properly.
Make sure when the car is off. The boost vale somes to rest @ its stop.

 

What do you mean boost vale rest? like goes to 0? I don't understand.

 

By pass valve (BPV), looking at the intercooler, place your hand to the right of the intercooler output duct and follow it down toward the intake manifold, the BPV has a small plastic arm attached to a lever, actuate (press) the little arm with your finger and feel for ease of movement, it should spring back contacting the end stop. If it doesn’t operate freely or doesn’t return, it will need replacement; it is a warrantee item.

My BPV failures manifested themselves at lower rpm but it's worth a look.

 

Just checked that and it was all springy. Looked fine. Any other sugestions?

 

After I chased around and changed both the TMAP and MAP sensors, thinking it was the BPV all the time, it was actually due to a vacuum leak. Find someone to do a "smoke test" on your intake.

Good Luck

 

A "smoke test" ? Could The MINI Center do this? Could you elabrate more on what this is?