[v8killah]

Hi,

I have an '08 335xi AT and while accelerating pretty vigorously, my car went into limp mode. I have a Cobb AP installed with Stage 1, and I used it to check the codes and then reset the ECU/codes. The codes continued to return with very rough idle and limited power. Here are the codes:

-P30BA: injector, power stage
-P29CD: cylinder #1 misfire
-P29CF: cylinder #3 misfire
-P29CE: cylinder #2 misfire
-P29CC: multiple misfires

I've read about fried MOSFETs on the DME, but it seems like only '07s are susceptible to that. Given that there are returning misfires all on the same bank, it makes me think that the problem is not related to plugs/coils/injectors. Anyone have any insight on what else it could be?

Thank you!

[GATORB8]

Relevant bulletin.

[v8killah]

Originally Posted by GATORB8

Relevant bulletin.

Thank you for looking that up for me! So if I'm reading it correctly (I have codes 30BA and 29CC that are mentioned in the bulletin), it's saying to replace all three injectors? What are the odds that all three injectors went bad at the same time? Doesn't seem to pass the common sense test.

[GATORB8]

Originally Posted by v8killah

Thank you for looking that up for me! So if I'm reading it correctly (I have codes 30BA and 29CC that are mentioned in the bulletin), it's saying to replace all three injectors? What are the odds that all three injectors went bad at the same time? Doesn't seem to pass the common sense test.

The injectors are supposed to be replaced in banks, so it could be to eliminate that one injector is bad. It may be part of the replacement deal BMW cut with the DME manufacturer.

Looks like the best next step is to multimeter the DME mosfets and confirm one is bad. If they are all good, then do the injectors. If it's bad, have the mosfet replaced:
https://www.youtube.com/watch?time_c...&v=P0_hFbNscCU

[v8killah]

Originally Posted by GATORB8

The injectors are supposed to be replaced in banks, so it could be to eliminate that one injector is bad. It may be part of the replacement deal BMW cut with the DME manufacturer.

Looks like the best next step is to multimeter the DME mosfets and confirm one is bad. If they are all good, then do the injectors. If it's bad, have the mosfet replaced:
https://www.youtube.com/watch?time_c...&v=P0_hFbNscCU

Thanks again! I think I'm going to pull the DME and give that a try since I have a voltmeter. To have three recurring misfires in cylinders 1-3, wouldn't that mean I would need to have three bad MOSFETs? Isn't that pretty unlikely, especially since they fixed the '07 issue with the MSD80 boards on the '08s?

[GATORB8]

Originally Posted by v8killah

Thanks again! I think I'm going to pull the DME and give that a try since I have a voltmeter. To have three recurring misfires in cylinders 1-3, wouldn't that mean I would need to have three bad MOSFETs? Isn't that pretty unlikely, especially since they fixed the issue with the MSD80 boards on the '08s?

My guess would be it has something to do with 1-3 being on the same bank. Hopefully someone with first hand experience will chime in.

[Koolsilver]

It could also be fuel pump related since it's multiple cylinders at once.

[v8killah]

Originally Posted by GATORB8

My guess would be it has something to do with 1-3 being on the same bank. Hopefully someone with first hand experience will chime in.

Yes, it would be interesting to know for sure. I did read that some '08s have an '07 build date and have the MSD80, so this may be plausible. Thanks again.

[torrque]

I have an 08, and it's still on MSD80 DME... so still susceptible to MOSFET issues. Not saying it's that. In my case it wasn't.

[GATORB8]

Originally Posted by v8killah

Yes, it would be interesting to know for sure. I did read that some '08s have an '07 build date and have the MSD80, so this may be plausible. Thanks again.

Note, you can find your build date by entering your VIN in a decoder, or find the month by entering it on the start page of realoem.com

[v8killah]

Originally Posted by Koolsilver

It could also be fuel pump related since it's multiple cylinders at once.

Good to know if the DME checks out OK. I had my high pressure fuel pump replaced under warranty about a year ago. Thanks

[v8killah]

Originally Posted by GATORB8

Note, you can find your build date by entering your VIN in a decoder, or find the month by entering it on the start page of realoem.com

Thanks, I'm going to try this when I get home from work, as I am using a borrowed car currently.

[v8killah]

Originally Posted by GATORB8

Note, you can find your build date by entering your VIN in a decoder, or find the month by entering it on the start page of realoem.com

Hmm, it says I have an MSD81... A fried DME was the only thing that made sense to me to cause the multiple misfires and the P30BA "injector, power stage" fault.

[v8killah]

Any final ideas before I limp it to the dealer? I am going to mention the fuel pump since they replaced the high pressure fuel pump a little while ago. Other than that, I'm coming up empty for a common cause for all of the misfires...

[GATORB8]

I would check the DME to confirm model, should only take a couple minutes.

If it's the Mosfet's, I assume the dealer won't consider repair and will recommend replacing the DME for at least a couple grand. Three injectors were around a grand at the dealer here IIRC.

I recommend find a reputable local independent if you are going to take it somewhere, hit up the local chapter of BMWCCA on facebook and ask for a recommendation.

[whyzee125]

If your car isn't from 07, it's very unlikely it's your mosfets. I could be wrong but I think I had one coil cause multiple cylinder misfires to occur. Replaced them all. Good luck.

[v8killah]

Thanks again all. Very much appreciated! I'm taking it to an independent import car place to continue the diagnosis...

[v8killah]

Well, it was three fried MOSFETs... Mailing it in for repair and hopefully there's nothing else after that. Thanks all. I wish I would have just pulled it myself, but I lost hope it was a potential problem since I have an '08.

[GATORB8]

Originally Posted by v8killah

Well, it was three fried MOSFETs... Mailing it in for repair and hopefully there's nothing else after that. Thanks all. I wish I would have just pulled it myself, but I lost hope it was a potential problem since I have an '08.

Sometimes just knowing the answer immediately is worth the cost of having someone look at it.

Good that they're working with you on a repair instead of insisting on replacement. Dealer would have hit you pretty hard for a new one.

[v8killah]

Should I change my oil after the misfiring on the cylinders 1-3 bank? With this DME issue, are the injectors expelling any fuel or do they just not work? If they are expelling fuel, I was wondering if any of it is getting into the oil since it is not getting burnt off.

Thanks

[bluemonstr]

Originally Posted by v8killah

Should I change my oil after the misfiring on the cylinders 1-3 bank? With this DME issue, are the injectors expelling any fuel or do they just not work? If they are expelling fuel, I was wondering if any of it is getting into the oil since it is not getting burnt off.

Thanks

Coming into this a little late - but just want to give you a heads up. I went thru this issue earlier this year (last Jan)...I replaced all 6 mosfets with a friend of mine AND I had a dead fuel injector AND coil pack. Apparently sometimes when the mosfets go, they take other things out with them. SO, if after you re-install your DME - and you still get misfire - this may have occured.

As far as your oil change...where oil and gas are concerned, you can never be too safe.

Also - when you sent it out...I hope you told them to replace ALL mosfets. Might as well take care of it now.

[v8killah]

Originally Posted by bluemonstr

Coming into this a little late - but just want to give you a heads up. I went thru this issue earlier this year (last Jan)...I replaced all 6 mosfets with a friend of mine AND I had a dead fuel injector AND coil pack. Apparently sometimes when the mosfets go, they take other things out with them. SO, if after you re-install your DME - and you still get misfire - this may have occured.

As far as your oil change...where oil and gas are concerned, you can never be too safe.

Also - when you sent it out...I hope you told them to replace ALL mosfets. Might as well take care of it now.

Thanks for all of that. All were replaced. We will see what happens once she goes back in (fingers crossed). Noted on the oil change. Will do.