[triax37]

Christmas tree appeared yesterday. From searching and reading other threads (thank you, search!), it's likely the alternator, voltage regulator, or the battery. Any opinions or experience? Below are the errors (from ISTA). Thanks!!!

2A3F - DME: Valvetronic, actuator motor: power supply
2DEB - DME: Power management, vehicle electrical system
2E85 - BSD, message: electric coolant pump: Missing
2E98 - BSD, message: alternator: Missing
571D - EGS: Supply voltage: overvoltage
581A - EGS: signal fault, wheel circumferential velocity front left from DSC
581B - EGS: signal fault, wheel circumferential velocity front right from DSC
581C - EGS: signal fault, wheel circumferential velocity rear left from DSC
581D - EGS: signal fault, wheel circumferential velocity rear right from DSC
5DF7 - DSC: system voltage too high
931D - KOMBI - undervoltage or overvoltage
93D1 - MRS: overvoltage
940A - MRS: overvoltage during self-test
9C6C - IHKA: Supply, switch center, center console 12v
A0B5 - CAS: Fault, road speed signal
A6CF - JBE: AUC Sensor
C910 - No message, receiver JBE, transmitter IHKA
CD95 - Message (operations, cruise control/ACC, 0x194), faulty, receiver DME, transmitter
D364 - Message (KOMBI, 0x194) missing, receiver DSC, transmitter KOMBI
D373 - Message (steering column switch cluster, 0xC8, 0xC9) missing, receiver DSC

[Welcome to NBA Jam]

Start with the battery. It's the easiest and cheapest thing to change. After that, go with the voltage regulator.

[triax37]

Originally Posted by Welcome to NBA Jam

Start with the battery. It's the easiest and cheapest thing to change. After that, go with the voltage regulator.

There is a voltage regulator near me for $20, so much less than the cost of a battery (which is also not near me). I would appreciate hearing any other experience with power related codes.

[Mark963]

If you have the codes, don't you also have the voltage while running? If the charge voltage is low, that's a possible sign of a failed regulator.

[gbalthrop]

Originally Posted by triax37

Christmas tree appeared yesterday. From searching and reading other threads (thank you, search!), it's likely the alternator, voltage regulator, or the battery... Below are the errors (from ISTA). Thanks!!!
...
2A3F - DME: Valvetronic, actuator motor: power supply
2DEB - DME: Power management, vehicle electrical system
571D - EGS: Supply voltage: overvoltage
5DF7 - DSC: system voltage too high
931D - KOMBI - undervoltage or overvoltage
93D1 - MRS: overvoltage

Uh... You have AT LEAST 6 Fault Codes for "Over-voltage" or Alternator Output voltage with engine running in the 16V to 17V range.

Change the Voltage Regulator on your Alternator. If this is a 2007 E91 with N52K engine, that has 180-Amp Bosch Alternator, and this is the $33 part you need:
https://www.autohausaz.com/pn/BS-12317561939

If you look at Fault Details Tab (click on Fault row in ISTA "Fault Memory" screen and you get a "Details" Tab) you SHOULD see actual "Freeze Frame Data" Voltage Value, e.g. 17.2V, for SOME of the Faults above. That is the actual Voltage at the moment that fault code was saved. You do NOT need to retest measuring system voltage with motor running.

Here are several examples of info from BMW Fault Code Lookup, including links to "Fault Information" sheet:

https://bmwfault.codes/
2A3F | DME: Valvetronic, actuator motor: power supply | msv80
https://bmwfault.codes/XMLDiagView?d...IAOQAyADAANAA=

2DEB | DME: Power management, vehicle electrical system | msv80
https://bmwfault.codes/XMLDiagView?d...UANQA1ADAANAA=

Learning HOW to Diagnose, and taking the TIME to Diagnose, $AVE$ TIME & Money throwing parts. You have ISTA. That basically gives you what you need, at least with Forum Help on HOW to best use it.
George

[triax37]

Originally Posted by gbalthrop

Uh... You have AT LEAST 6 Fault Codes for "Over-voltage" or Alternator Output voltage with engine running in the 16V to 17V range.

Change the Voltage Regulator on your Alternator. If this is a 2007 E91 with N52K engine, that has 180-Amp Bosch Alternator, and this is the $33 part you need:
https://www.autohausaz.com/pn/BS-12317561939

If you look at Fault Details Tab (click on Fault row in ISTA "Fault Memory" screen and you get a "Details" Tab) you SHOULD see actual "Freeze Frame Data" Voltage Value, e.g. 17.2V, for SOME of the Faults above. That is the actual Voltage at the moment that fault code was saved. You do NOT need to retest measuring system voltage with motor running.

Here are several examples of info from BMW Fault Code Lookup, including links to "Fault Information" sheet:

https://bmwfault.codes/
2A3F | DME: Valvetronic, actuator motor: power supply | msv80
https://bmwfault.codes/XMLDiagView?d...IAOQAyADAANAA=

2DEB | DME: Power management, vehicle electrical system | msv80
https://bmwfault.codes/XMLDiagView?d...UANQA1ADAANAA=

Learning HOW to Diagnose, and taking the TIME to Diagnose, $AVE$ TIME & Money throwing parts. You have ISTA. That basically gives you what you need, at least with Forum Help on HOW to best use it.
George

George! I was hoping you would see this thread and share your expertise. I checked the 2A3F and 2DEB codes and the voltage at Terminal 87 was 17.5-17.6. ISTA also shared that my battery over the past 5 days peaked at 58% after two hour-long drives, and reached a low of 36% when these errors started appearing. Does that lead anyone to think more about the voltage regulator or the battery? The battery is currently holding at 12.5v.

And yes, I'm certainly learning to diagnose, and ask questions, and have no interest in throwing parts at a solution. Thank you to the great members of the forum that help answer questions and guide people who want to learn (like me!).

[gbalthrop]

Originally Posted by triax37

... I checked the 2A3F and 2DEB codes [I presume you mean "Details" or FF Data?] and the voltage at Terminal 87 was 17.5-17.6. ISTA also shared that my battery over the past 5 days peaked at 58% after two hour-long drives, and reached a low of 36% when these errors started appearing. Does that lead anyone to think more about the voltage regulator or the battery? The battery is currently holding at 12.5v.

Your Battery is FINE! Get the correct Voltage Regulator for your vehicle, after checking to make sure you have the original Bosch 180-Amp alternator, and NOT some off-brand. At $33 or so, that should be the ONLY part to throw at it. Battery CANNOT cause Over-voltage. That is a condition that occurs when engine is running and Alternator is charging the battery.

Using the "Water Pressure Analog" for Electrical Voltage, water/electrons flow from Higher pressure/level to Lower. Alternator is putting out 13.5V to 15.0V during normal operation/ Engine running. That higher "Pressure/Potential" "pushes electrons" into the battery. As long as the Alternator Diodes (electrical Check-Valves) are OK, those electrons do NOT flow back to the Alternator from the Battery after engine shutdown.
George