2007 Mini CooperS Code P0012
In almost all cases a code P0012 is either a failing Vanos solenoid valve or to a lesser extent a failing Vanos itself. We have run into this scenario many, many times. But this one had us stumped. We also had what we thought was the normal loud timing chain rattle. We replaced the solenoid and Vanos with known good parts and the code would return almost instantly. We had great oil pressure at the oil pressure sensor in the cylinder head. We removed the front cam cap just behind the Vanos and found that the cam bearing had oil but the channel to the Vanos was dry. After getting a copy of the oiling diagram it was clear what the problem was. The non-return check valve in the cylinder head was stuck shut and starving the Vanos for oil. That passage also feeds the timing chain tentioner but oil passages for the lifters and cam bearing branches off before the non-return check valve. We replaced the non-return check valve and solved our P0012 problem and the chain rattle went away too. So if you get a Mini Cooper with a code P0012 and you have tried everything else, pull the front cam cap and check the Vanos feed channel for oil. You may have a sticking non-return check valve.
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