[Vinnief96]

07 328xi with 156k miles. Recently 4x4 light, dtc, and abs light have been periodically popping up. Accompanied a few days later by the radio shutting off and the windows not working. Assuming this is a battery fail safe. Pulled codes and got 2E98 and 2E81. Alternator missing, cooling pump deviation. Read a lot and hear this could be alternator issue or battery as they are ran of the BSD bus. All alternator connections seem fine all grounds look good no corrosion. Tested battery with car running it checked in at 13.4v. with car off and battery out tested with 12.26-12.35. Is this possibly a bad battery not holding load/charge causing these codes? A Bmw buddy of mine said he thinks it would pop more codes if it was a battery. Not entirely sure and don't want to spend $200 for it to not be the issue. TIA

[ctuna]

If your getting messages from the water pump it usually means it's on the
way out . No communication is what happens when it fails along with overheating.

I would physically check the battery area.
Be sure there is not water in the battery area.

Measure the battery in the morning before the first start.

[vilord]

the lights popping on and windows stopping working while driving kinda sounds like a short somewhere in one of the can buses, not a battery issue... though that would throw some hidden codes too.
What are you using to read the codes? You'll probably want to scan it with something like protools if right now you're just using a basic code scanner...

[Vinnief96]

Originally Posted by vilord

the lights popping on and windows stopping working while driving kinda sounds like a short somewhere in one of the can buses, not a battery issue... though that would throw some hidden codes too.
What are you using to read the codes? You'll probably want to scan it with something like protools if right now you're just using a basic code scanner...

I'm using a Bmw scanner hence the hex codes given… isn't the water pump on the same bus as the alternator? so would both those codes indicate the water-pump specifically? I took the entire battery out and saw no signs of water. I don't see any corroded or messed up wires either. These are the codes I'm reading on my scanner. I only read dme specific

[Vinnief96]

Originally Posted by ctuna

If your getting messages from the water pump it usually means it's on the
way out . No communication is what happens when it fails along with overheating.

I would physically check the battery area.
Be sure there is not water in the battery area.

Measure the battery in the morning before the first start.

Tbh, I have a hunch that this code may be due to low coolant…. Just checked it and it's kind of low.

[ctuna]

Cooling Pump deviation is a water pump error code.

[Vinnief96]

Originally Posted by ctuna

Cooling Pump deviation is a water pump error code.

It's also known to pop up with low coolant which I did in fact have. Coolant pump deviation doesn't necessarily mean specific to the coolant pump either imo since again several things run of the same bsd bus including the alternator. I can't rule it out since an issue with one thing on the bsd bus can cause a code for something irrelevant also on the bsd bus from what I'm told. since I have 4x4 lights dtc, abs, and radio randomly shuts off, it Just doesn't correlate to actually being a water pump issue. My main question concern was if 13.4v is too low for a battery with an engine running

[ctuna]

13 to 14.5 is the normal range.
I would put a full long slow charge on the battery
to see if it makes any difference.

Too test the water pump you could run the purge procedure
which exercises the pump to get the air bubbles out of the
cooling system . It runs for maybe 10 minutes . Before you do it
make sure you have a fully charged batter and/or a charger standing by.

[StradaRedlands]

Originally Posted by Vinnief96

I'm using a Bmw scanner hence the hex codes given… isn't the water pump on the same bus as the alternator? so would both those codes indicate the water-pump specifically? I took the entire battery out and saw no signs of water. I don't see any corroded or messed up wires either. These are the codes I'm reading on my scanner. I only read dme specific

The BSD has water pump, alternator, and oil level sensor. Maybe more, but those for sure. A problem with one can throw codes in all of the above. Windows and radio aren't on it though.

[Vinnief96]

Originally Posted by ctuna

13 to 14.5 is the normal range.
I would put a full long slow charge on the battery
to see if it makes any difference.

Too test the water pump you could run the purge procedure
which exercises the pump to get the air bubbles out of the
cooling system . It runs for maybe 10 minutes . Before you do it
make sure you have a fully charged batter and/or a charger standing by.

Yesterday battery with engine running tested at 13.4v. Today the battery with engine running tested at 12.7. Leaning towards alternator- battery was load tested fine

[ctuna]

Yep that seem's low.
Where are you measuring the Voltage .
Another thing that happens with these is the ground strap
from Engine to Chassis Rots causing a Voltage drop between
the battery and engine components.

[Vinnief96]

Originally Posted by ctuna

Yep that seem's low.
Where are you measuring the Voltage .
Another thing that happens with these is the ground strap
from Engine to Chassis Rots causing a Voltage drop between
the battery and engine components.

I did check the ground straps and they are still good. I actually replaced them about 30k miles ago due to them being rotted through. I checked the voltage directly at the battery terminals

[Vinnief96]

UPDATE TO THIS POST IN CASE ANYONE ELSE HAS THIS ISSUE (SO FAR SO GOOD): had a hunch it was the alternator, so went ahead and replaced that. Lights stopped popping up all issues (fingers crossed) are gone. Been a little over a week