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Roger, BMW Master Tech
Category: BMW
Satisfied Customers: 5882
Experience:  10 yrs. experience as BMW Master Technician, shop foreman and dealer.
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2003 bmw 325i: I got a misfire code..auxillary..entail..spark plugs

Resolved Question:

I got a misfire code on 2003 bmw 325i and an auxillary input in and out code what does this entail and how do I get to the spark plugs
Submitted: 8 years ago.
Category: BMW
Expert:  Roger replied 8 years ago.

Hello. I will try to help you with this. I will provide the instructions for replacement of the spark plugs but a misfire can be caused by many reasons and a code reader might be needed to diagnose this problem. The first thing to check would be to see if you have bremi or bosch coils installed on this vehicle as you are getting to the spark plugs. If you see bremi then most likely you have a bad coil but a bad bosch could be likely as well. We have a know issue with bremi's so let me know if you find them. You will see the name on the top of the coil at the connector.

It could just be spark plugs, or you could have a leaking injector, or a mechanical defect in the engine like a bad valve. The first step is to suspect the coil. Find out what cylinder has the fault like misfire in cyl 3 and then swap that coil to say cyl. 1 to see if the fault then moves to cylinder 1. If it does then you know it is a bad coil. You can also do that with a fuel injector say the misfire is in 3 and you already moved the coil then swap the injector to cyl. 2 and see if the misfire moved to cyl. 2. Also it would not hurt to change the spark plugs if they have not been changed.

GRRA1212-05Cover of ignition coil cover: Unclip cover caps from screws and release screws. Remove sealing cap (1). Remove cover from ignition coil cover. Screw cap (1) back into cylinder head cover.

Switch off ignition.

GRRA0000-INFORemove cover for ignition coils.
GRRA5012-028Version with single-spark ignition coils: Unlock connector of ignition coils. Disconnect connector from ignition coils.
GRRA1212-13Unfasten screws on ignition coil. Pull out ignition coil. Installation: Screw down grounding strap (1) to cylinder head cover mounting and to ignition coil for cylinders 1 and 6. On metal covers: Screw down grounding strap of cable duct to cylinder head cover mounting between cylinders 2 and 3.
GRRA1204-01Installation: M52 plastic cover: Screw down grounding strap (1) of cable duct with connecting plate (2) of ignition coils.
GRRA1108-29Installation: Plastic cover M52TU, M54: Screw down grounding strap (1) of connecting plate of ignition coils with retaining pin of ignition coil of cylinder 1. Screw down grounding strap (2) of cable duct with connecting plate of ignition coils between cylinders 2 and 3.
GRRA1213-61Version with rod-type ignition coils: Unlock plug retainer of ignition coil (1) and disconnect plug. Pull ignition coil (1) up and out.
GRRA1213-62Installation: Check that rubber seal of ignition coil (1) is correctly seated.
GRRA0000-HINWEISNote: Interrogate fault memory of DME control unit. Check stored fault messages. Now clear the fault memory.

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Customer: replied 8 years ago.
Thanks for the answer. The car does have bosch coil packs but my parts store doesn't carry them. The car is running fine every time I check it out but my wife says that in the mornings when she cranks up it runs OK for a minute, then starts missing really bad. I don't know if it is because she is allowing the car to warm-up while she idles or not. Could that be a problem? I read in the owners manual to not allow the car to idle when you first start-up. It said to just drive at a moderate speed until the car is warm. Any additional information you could give me on this matter would be greatly appreciated.
Expert:  Roger replied 8 years ago.

Hello. It is always a good idea to let the vehicle warm up before starting off to prevent engine wear. Their are other two things it could be beside the items I described earlier. The VANOS unit could be failing-this would take a dealer to diag. The check is to unplug both the inlet and exhaust solenoid valves on a cold start to see if it runs good. If it does then the VANOS is not working properly and the fix can be a bit expensive. The other item is also expensive and would involve the HVAC's or hydaulic valve actuators (camshaft lifters). The sometimes bind under cold start and can cause a misfire issue on cold start. These items are for your information as the basics should be performed before faulting these items. The basics would be spark (plugs/coils) ,fuel(pump pressure/regulator/injectors), air(no air leaks, mass air flow sensor, clogged engine air filter). If the problem is good when the veh. warms up that might be the best thing to just let it warm up. Also one bit of advise I would have is to perform an oil service even if it is not due--if the lifters are binding sometimes this will help with the problem. I would also double the oil changes from the normal reading. Thank you and let me know if I can help you further.

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