I have 3 fault codes showing but cannot get any answers to what they are please help as my bmw e90 330d is not running right codes ar DF 122, DF 031 and DF001

run the fault codes to see what put the engine light on
engine lights operate for engine faults and transmission faults
during the ac repair , a wire could have become disconnected
Consider it as a unrelated problem to the AC

To answer your question, yes it can cause permanent damage. please refer to the below information for more information on what happens during this process. Car Talk How much damage does starting an already running car do

http://www.bmwforums.info/bmw-electrics-ecus/7745-bmw-fault-codes-meaning-bmw-fault-codes-list.html

the error codes are BMW specific and yes an error code would show up as a cam position sensor fault.

IF there is a sleeve around the spark plugs then when replacing the plugs replace the seal under that sleave as well or rocker cover oil will leak out past the plug base.. If you want the correct oil filter you may have to buy genuine . Run fault codes to find the reason for rough idle . It may be a vacuum hose is off or cracked or loose.

Have you run the fault codes first as it may not be the fuel pump. Find out what is faulty before you spend good money on what is not faulty.

df006

The error shows as a "Turbo Charger Bypass Valve Control Circuit High" error. Let me guess, you don't have turbo, right?

Possiblities:

Did you recently "top off" your last gas fill? If so the error might go away on its own.

Is there a lot of moisture where you live? Ignition contact might have gotten wet.

Possibly a piece of carbon blew out of the manifold.

Does the car stall when you stop or while taking turns slowly? Might be cam position sensors.

Sorry for the vagueness but without using a Peake analyzer tool to isolate the problem it makes it difficult to give you the exact reason.

check fuel n air filter if not then u need a shop sorry hard code

How does the car start and run? If Ok, I would make sure the computer housing is properly grounded. Grounds are normally the problem when getting wacky readings.

I bet the car runs fine, Correct?

Good Luck