Need help

BrazjhanN54

New Member
Feb 13, 2021
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I’m getting these codes

2E7C bit serial data interface , signal
2E8B intelligent battery sensor , signal
2F6C exhaust fumeflap
2D20 accelerator pedal module ,pedal sensor, clause ability between signal one and two (this one comes and goes every now and then when I clear it )
2E84 electric cooling pump communication
2C6D lambda probe behind catalytic converter, aging

Background : I got my water pump and thermostat replaced like 200 miles ago and I got a new pedal from a donor car when the 2D20 code came up the first time, since then the code has been coming in and out. Oh and also lately when I hit a bump or pothole at the right speed, I go into limp and 2d20 comes up. Idk what to do or look for to fix these codes. I’ve replaced the peddle, water pump/thermo, and I’ve even tried to charge the battery. Idk what to do any more
 

Jeffman

Captain
Jan 7, 2017
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You’re N54, correct? Make sure the battery is fully charged. Lots of codes pop up when the battery gets low, which happens more frequently in the cold weather. Since I’m not driving her as much these days I keep her plugged into a battery tender which seems to work great.
 
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NoQuarter

Major
Nov 24, 2017
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Indiana, USA
Ride
Z4 35is, 535xi, X5 35i
Agree on the battery testing or replacement

Have you been under the intake lately?
Maybe remove that and have a look for wires chewed on by critters.
 

BrazjhanN54

New Member
Feb 13, 2021
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Okay I’ll try and replace the battery, but do those codes usually come up with just a dying battery ?
 

NoQuarter

Major
Nov 24, 2017
1,545
960
0
Indiana, USA
Ride
Z4 35is, 535xi, X5 35i
All kinds of weird sh$t happens. It is unpredictable.

It could turn out to not be a battery problem but you can't troubleshoot this if that is out there as a possibility.

New battery, fully charged, clear all the codes. Start from there.
 
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BrazjhanN54

New Member
Feb 13, 2021
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Update. I resolved the battery and after around 20 mins of driving home, those codes came up again and threw me into limp with lots of power loss and peddle barely responds enough for me to get the car home
 

BrazjhanN54

New Member
Feb 13, 2021
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Update. I resolved the battery and after around 20 mins of driving home, those codes came up again and threw me into limp with lots of power loss and peddle barely responds enough for me to get the car home
*ive replaced the battery
 

NoQuarter

Major
Nov 24, 2017
1,545
960
0
Indiana, USA
Ride
Z4 35is, 535xi, X5 35i
Search for videos on replacing DME mosfets (not saying that is a problem here).

Find a video that shows info on how to get to the DME box, remove cable connections, etc.

Look for evidence of water in the box, looks for corroded pins in the cable connections, and so on.
 

Jeffman

Captain
Jan 7, 2017
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At this point you should invest your time and money in a nice set of diagnostic tools and a good OBDII cable if you don’t already have them.
Rheingold ISTA+ is most comprehensive. Search BMW rheingold ista for free installation, and also for training. Lots of YouTube videos etc, like this
 
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JBacon335

Corporal
Nov 7, 2016
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Toms River, NJ
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07 335i Sedan, 1988 Mustang GT
I was thinking maybe look at the wiring by the water pump and thermostat. If I recall correctly, if one of those was broken (I'm thinking the thermostat wire) it would throw all those communication codes
 

BrazjhanN54

New Member
Feb 13, 2021
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Okay so another update I reflashed my backend map on mhd and did a few pulls and it seemed to be working fine. But now today it’s throwing just 2d20 (plausibility between signal one and two) and 2c7b lambda probe behind cat converter 2.