[desertman123]

2014 BMW 528i (F10) with ~41k mi on it. Posted this on the F10 forums but I'll probably get more answers here.

So I got a CarlyBMW scanner and I did some coding for my parents' car. Disabled auto start/stop, got rid of the lawyer warnings and a few other things.

I scanned the car for faults just to see what would pop up, and to my surprise the car came back with cylinder 2 and 3 misfires! No CEL/SES.

 Misfire, a plurality of cylinders: detect
        Code: 140010
      Misfire, cylinder 3: detected
        Code: 140310
      Misfire, cylinder 2 detected
        Code: 140210
      Misfire, a plurality of cylinders: harmful exhaust after startup
        Code: 140002
      Misfire, cylinder 3: harmful exhaust after startup
        Code: 140302
      Misfire, cylinder 2: exhaust harmful after startup
        Code: 140202

My mom noted the car felt fine, no vibrations, but feels her gas mileage isn't as good as it should be (which corroborates a misfire -- and this is before I disabled AS/S).

I cleared the engine faults (among a bunch of other random ones) and drove it around, flooring it to redline a few times, but they didn't return. Although I did only drive it about 10-15mi, so I don't know if that's enough time to allow the codes to reappear.

I'll be back at my parents' next weekend, so I'll rescan it then, and if the codes appear I'll send it to BMW (it's still under warranty.) Might just need spark plugs and a walnut blast, but it seems early for all that.

[XKxRome0ox]

why would you clear the codes when the car is under warranty? should have taken it to the dealership immediately

[desertman123]

Originally Posted by XKxRome0ox

why would you clear the codes when the car is under warranty? should have taken it to the dealership immediately

No CEL and basically no symptoms.

What should I tell them? My 3rd party BMW scanner is telling me I have issues?

Although you do have a point.

[XKxRome0ox]

Originally Posted by desertman123

No CEL and basically no symptoms.

What should I tell them? My 3rd party BMW scanner is telling me I have issues?

Although you do have a point.

you take it in, tell them the codes you found
let the dealership verify and put it in their service record

that way, if the car does get a CEL and/or experience other problems within the warranty period, you have more records to support a potential lemon law claim

[X2 Monstah]

My 328i had a drivetrain malfunction a couple of weekends ago. When the dealership checked it out, they found codes for cylinder 2 misfiring. They pulled the spark plugs and found them to have fairly heavy carbon deposits. They cleaned the plugs and I have had no issues since then (although I just got the car back on Monday). I did notice a decrease in gas mileage between the time I got the malfunction and when they fixed the issue (drove 500+ miles before the car was taken in, as I was out of town). Since getting it back, my gas mileage has been great (again, only a few days).