2nd Gen R56 Cooper S Most liked posts in thread: Half Yellow Engine Light without Error Codes?

My experience has been that if there is a leak from the airbox to the turbo that you'll get a check engine light on the center console, not the half-engine one. I busted my inlet hose and learned that one. That was a simple fix.

So far for me the half engine light has only come on for issues in the turbo itself (busted waste-gate) or a massive oil leak (it bled out on to the street one day all at once).

I'd start by looking at the fittings from the airbox to the turbo, see if they're all tight and that you have no cracks or loose connections. Check the crank case vent hose as well, as it can get loose sometimes. It branches from the inlet hose to the top of the engine.

After those simple checks, you'll need advice from someone with more expertise than me.

 

I'm not familiar with Torque, but generic OBD2 scanners won't see proprietary MINI codes. You'll need to find a tool designed specifically for the MINI to see all of the codes.

 

Check all your connection, make sure there is a not a small leak in the intake system.

 

Make sure these fittings are tight.

I'm still kind of leaning to something a bit more serious though. Hopefully someone with more skill will chime in.