Engine warning light?

[butch]

A yellow engine warning light continues to illuminate periodically in my 2007 335i. It's been on and off for a few weeks. The check engine soon message was also displayed for a few days last week. I made an appointment and left the car wth the dealer however neither of the warning lights were on when I dropped her off. The dealer was not able to determine the problem claiming that the lights need to be illuminated in order for the computer to locate the cause. They did "change the cylinders" (not sure what that means) in an attempt to correct the problem. Unfortunately, the warning light came on again yesterday.
This is my 3rd BMW and I've never encountered any service issues that weren't handled promptly and to my satisfaction. I guess what I'm wondering is shouldn't the dealer be able to figure this thing out without me having to roll into their service bay with the warning light shining? For a second I felt like I was talking to the service tech at a Chevy dealer. This isn't a plea to diagnose what's wrong with my ride. I'm just wondering if their position is valid or is it time for a more animated discussion with the Service Manager. Your opinions/advice are really appreciated.
thanks,
butch

[zibby]

I would talk to service manager ASAP.Actually blinking "check the engine light" indicates more serious problem than steady one(if happens often, engine damage may occure).

[Dirty_Tool]

SES lamp will normally leave a code stored in the engine module which can be pulled up after the fact. Same thing with general check control messages.. they are stored in history. Since they said they "swapped cylinders" im wondering if you had a misfire fault but it was not currently present so maybe they swapped coils, plugs and or injectors to another cylinder to see if when the fault returns it moves to whichever cylinder they swapped it to. Do you have any other symptoms besides the light? Misfiring, shaking, hard start etc. Also make sure with that car that you always run 91 octane or higher "top tier" fuel.
Best Regards,
DT

[Steve@ASPTuning]

Sometimes the "yellow check engine light" means your gas cap isn't tight. Tough you think its tight like I did myself but really un screw it, and then like hold it down towards your gas tank tightly, and screw it tight.

See if that goes away after a few hours. Generally the yellow engine light has to do with your emissions systems.

Hope that helps.

Steve
ASPTuning

[darkhorse737]

in an OBD2 system, a blinking CEL always means misfire in one or more cylinders. Eventually after a # of misfires, the CEL will remain steadily on if the misfire hasn't corrected

And yes, irregardless of whether CEL is lighted or not, the ECM has a memory that stores the car's faults...