I changed my oil in the 530 xi 2006 how can

The voltage is ok, maybe the pump's fuel pressure check valve is defective and the fuel pressure bleeds off and that causes a hard start.

"Diagram?" Really?
PLEASE BE MORE SPECIFIC. WHAT DIAGRAM??????
Also, try doing a Google search to find what you're seeking.

put the key on acc then push milage to zero and hold it turn key to on and watch milage meter. hope it works. if not take neg post off batt for 20min

how can i clear the code

The battery needs to be registered to reset the energy data that is stored in the vehicle.Without this being done you may run into short battery life and possibly energy consumers shutting down (ie the blower not working at full speed)

The dealer knows the sequence of buttons to push to reset the indicator. It's just a milage counter it doesn't involve any sensors monitoring the oil, it's condition or your oil pressure.

Take it to the dealer, takes about 2 minutes.

BMW uses Casteroil 5W-30 Full Synthetic Oil in all there engines except the M-series. After changing the oil the service light will nedd to be reset by the dealer, this is the only way it can be reset, it is part of the new Condition Based Service (CBS) system. Hope this helps, let me know.

Both, it has an On Board Diagnostic computer, or OBD-II. For giving problem codes. But as far as in tune up wise, only has one for the oil.

Turn the engine off with the key in the the accessory position so you can see the info display. Press the info button until the Oil Change info is shown. Hold down the info button and it will ask to 'clear', press the info button again. Done!
Good luck

The negative number means the car should have had it's oil changed that many miles ago. Oil life starts at 100% for new oil & counts down every 10%. At 15% the display will always show, which means it's near time to change the oil.

usersteve83, your oil may have been changed but the timer not reset. Reset the timer as shown...
1. Turn ignition to the "ON" position. (do not start engine)
2. Press SEL/RESET repeatedly until the oil life indicator is displayed.
3. Press & hold the SEL/RESET for about 10 seconds until it blinks then let go of the button.
4. Press the SEL/RESET again for about 5 seconds or until the oil life indicator resets to 100%.

Wrench = Maintenance Minder: Symbol letter & number...
Symbol A - Relace engine oil.
Symbol B - Replace engine oil & filter, Inspect front & rear brakes, Check parking brake adjustment, Visually inpest the tie rods, suspension components,driveshaft boots, brake hoses & line (including ABS), all fluid levels & their conditions, exhaust system, fuel lines & connections.
Symbol 1 - Rotate tires.
Symbol 2 - Replace air cleaner element (dusty conditions every 15K miles) & replace dust & pollen filter (behind glovebox) every 15K miles if mainly dusty or city driving.
Symbol 3 - Replace transmission fluid.
Symbol 4 - Replace spark plugs.
Symbol 5 - Replace engine coolant.

All above are taken from the 2006 Civic EX owner's manual.