20 Most Recent 2004 BMW 3 Series - Page 3 Questions & Answers

there should be a large plastic cover on the engine , sometimes these don't get replaced as the vehicle gets older and more people work on it , you will see where the spark plugs are screwed into the engine as there will be wires at even intervals , these are the plug leads , pull them off , some times there is a screw/bolt that needs to be removed, you will then have access to the plug

YOU NEEDTO scan for security breach. THE SCANNER will give you a code referring to failed security point. IT COULD BE A BAD KEY.It could be quite a number of things that cause it since all the doorsincluding the hood and trunk havesensors. If there are no codes relating to security then look for a mechanical failireif the shift mechanism on the transmission end or thesensor on thegearshift end.

Check PCV valving to the intake manifold most often the diaphragm is broken which allows extreme vacuum to be applied to the crankcase.Will cause many codes relating to lean fuel mixture bad map readings fuel trims way off. With the engine idling remove the oil fill cap and note the vacuum. It should be very slight.;almost undetectable. I know there are specs relation to in/hg but if you don't have the tester the spec is unusable. Replacing the valve is difficult/expensive. I have replaced many and they never get easier.

thermostat or headgasket

Take the car to an AutoZone IF it's driveable, ask for the free check on "alarms" and they can set it up to reset.