[lcasale]

So I just gotten my 2008 335xi back from the dealership last week where they did a walnut shell blasting and vacuum hose replacement (to fix a boost leak). I immediately reinstalled the JB4 and on my way to the airport Friday, during a hard acceleration, limp mode was triggered and the CEL was blinking and the transmission light turned on.

I've never seen the blinking CEL before but after reading it's just a safety feature of the JB4. So when I flew back Sunday I was expecting the car to run normally again, however the car was still in limp mode without any warning lights. I thought I blew up my chargepipe. When I got home I took a look but couldn't see anything wrong with the CP. I pulled up the codes and here's what I had...

29D1 Misfirings, cylinder 5
29D2 Misfirings, cylinder 6
29D0 Misfirings, cylinder 4
2B2C No Description Found
30FF Boost under target -- possible boost leak
0000 Unknown Fault

This morning I cleared the codes and removed the chip ready to take it back to the dealership, but the car drove fine.

When I was removing the chip, I noticed the green flap that holds the power plug in place was loose and the power cable may have come out. But I can't confirm whether or not this happened from hitting a bump (gotta love the roads around LaGuardia) vs. me pulling the cable out of the harness. But would the power cable coming loose cause this? Or would it be much worse?

I'm going to postpone the dealership visit but does anyone have any idea what might have happened? I ran the car hard this morning without the chip and didn't have any issues.

[The1ontop]

We'll the flashing light is because there are multie misfires and in your case I would consider the fact that you could need new plugs or coils for cylinders I got the wallnut blast and installed the jb and I needed new plugs and a cpl new coils short after. it is common to only have symptoms while the jb is engaged because you are running higher leves then stock so your symptoms won't show up when your stock start with plugs then coils if your problem persists

[lcasale]

Whoops, should have mentioned that I just swapped out all the plugs less than 1000 miles ago. I'll definitely swap and check out the coils next. I guess I just found it strange that I was still in limp mode after a car restart and got the 2B2C and 0000 codes. A few bad coils wouldn't cause that, would they?

[Fillyo75]

^^^^ absolutely

[lcasale]

But wouldn't the car go back to normal after a restart and then go back into limp mode if another misfire happens?

edit: Or would the car stay in limp mode until those codes cleared?

Sorry if it's a dumb question, I'm just trying to expand my knowledge.

[Jhe]

If your pwr wire isn't secure, It most definitely could cause issues. I would start by securing that as best you can.... If it is loose, you'll create an arching effect, Kinda like a plug in your house not plugged in all of the way. This will cause un even pwr delivery, also pose a threat of electric fire or frying your circuit board, especially under load in a 12 volt system.

[2blu4u]

bro I litteraly did the same thing and got the same codes, 4,5,6 misfires then I got another one for multiple misfires and it ended up being my turbos were bad and intake valves needed to be cleaned. I had a lot of fuel in my oil too because from a friend (master bmw tech) said that the misfires shut the cylinder down as a safety feature but the injectors kept dumping fuel in.