Lean codes after battery death & replacement N55

vdwlkr · 03-14-2024, 09:21 AM

2011 335xi N55 MHD stage 2+ e30 blend AT
Data log: https://datazap.me/u/vdwlkr/2011-335...13-17-18-19-20

A few days ago, my battery died and I replaced with a new Diehard Plat AGM battery. The thing is, for the past 2 years the wrong battery was installed. My old AGM I bought the car with died in 2021, and being broke at the time, I bought a battery off FB marketplace. Being stupid, I was bamboozled into thinking it was an AGM by a fake label placed on the outside, but it was actually a diehard gold lead acid. Devious, and definitely tricked me. That being said, I assumed since it was an even swap, no coding or registration was necessary. The battery had continuous issues for the past year, and began dying a few weeks ago. Last week I jumped it, had it on trickle all week, and was welcomed to a dead battery a few days ago. Jumping wouldn't revive it this time, so I went off and got the new one. Coded to 70ah AGM in BimmerCode & registered it on MHD.

I took the car for 3 drives before I got an SES.
Active codes: 2BC0 Mixture control, fuel air mixture too lean - 36FD DME main relay, plausibility, prematurely dropped out - 387C Power management, battery total discharge - 3887 vehicle voltage, working area: voltage too low. The battery codes are likely from when the old one died, as I didn't clear the codes since; but the mixture control one was new.

Shadow codes: 2C42 Mixture control, multiple fault - 2D45 Valvetronic, adjustment range, stop not taught in due to ambient conditions

Driving, I can see small spikes in the AFR from 14.7 to 16.2 occasionally at bumper-to-bumper traffic speeds (thanks DC). WOT pulls hard initially, but felt like it tapered off weirdly - which is evident in the low peak boost numbers. On other less-formal autologs I hit 18PSI, but typically I see 21 at max. Idle feels good, WOT just feels a little weak on the upper-range, slow driving is intermittently sluggish and choppy.

Any ideas on where to start here? Planning to clean MAF & MAP tonight, and have heard fuel rail sensor & HPFP sensor can cause this.

03-14-2024, 09:21 AM	#1
vdwlkr New Member 0 Rep 11 Posts Drives: 2011 bmw 335xi Join Date: Aug 2020 Location: Virginia iTrader: (0) Garage List 2011 BMW 335xi [0.00]	Lean codes after battery death & replacement N55 2011 335xi N55 MHD stage 2+ e30 blend AT Data log: https://datazap.me/u/vdwlkr/2011-335...13-17-18-19-20 A few days ago, my battery died and I replaced with a new Diehard Plat AGM battery. The thing is, for the past 2 years the wrong battery was installed. My old AGM I bought the car with died in 2021, and being broke at the time, I bought a battery off FB marketplace. Being stupid, I was bamboozled into thinking it was an AGM by a fake label placed on the outside, but it was actually a diehard gold lead acid. Devious, and definitely tricked me. That being said, I assumed since it was an even swap, no coding or registration was necessary. The battery had continuous issues for the past year, and began dying a few weeks ago. Last week I jumped it, had it on trickle all week, and was welcomed to a dead battery a few days ago. Jumping wouldn't revive it this time, so I went off and got the new one. Coded to 70ah AGM in BimmerCode & registered it on MHD. I took the car for 3 drives before I got an SES. Active codes: 2BC0 Mixture control, fuel air mixture too lean - 36FD DME main relay, plausibility, prematurely dropped out - 387C Power management, battery total discharge - 3887 vehicle voltage, working area: voltage too low. The battery codes are likely from when the old one died, as I didn't clear the codes since; but the mixture control one was new. Shadow codes: 2C42 Mixture control, multiple fault - 2D45 Valvetronic, adjustment range, stop not taught in due to ambient conditions Driving, I can see small spikes in the AFR from 14.7 to 16.2 occasionally at bumper-to-bumper traffic speeds (thanks DC). WOT pulls hard initially, but felt like it tapered off weirdly - which is evident in the low peak boost numbers. On other less-formal autologs I hit 18PSI, but typically I see 21 at max. Idle feels good, WOT just feels a little weak on the upper-range, slow driving is intermittently sluggish and choppy. Any ideas on where to start here? Planning to clean MAF & MAP tonight, and have heard fuel rail sensor & HPFP sensor can cause this.
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