Frost1712

No problems with the alternator were noticed. The battery charge remains high (80+%) at all times. I did not check the charging voltage physically, but according to VCDS, it is a constant 14+V. The car is used every day in the city, averaging 50-70 km. It also stays in the garage for about a week every two months, as I go on business trips. Upon my return from a business trip, the battery remains charged at 12.6 V. I will check the alternator charge with a multimeter today, but I don't think there will be any problems.

Thanks for the idea! A small clarification: all several times the car stood for about 20 hours from the moment of closing. Also, about 12 hours after closing the car, the error U140B00 appeared Energy management system is enabled (I found this in the archive records after connecting to the car) I heard that the generator can give such an effect, but can it be so rare (once every 1-1.5 months)? How can I check the generator for such a problem?

A completely logical question. Yes, this is a regular diesel without 12-48v hybrid batteries. It did not occur to me to measure the current that the car consumes immediately after the battery is discharged, but since a completely serviceable battery is discharged overnight, it means that the current is at least 1-2 amperes. This is also indicated by the fact that the battery increases its voltage from 4-5 to 7v when disconnected.

Hi, Gareth Yes, that's right. After disconnecting the battery from the car, the voltage on the battery rises to about 7 volts. After that, I immediately put it on charge

Good afternoon! Four months ago I bought an Audi A4 B9 Allroad 2020. About a month after the purchase, one morning the car did not open with the key fob, only with a mechanical key. Having measured the voltage on the battery, I got about 4-5 V. The battery was still original, so I decided that it was out of order (internal short circuit) and replaced it with a new one from Varta, completely suitable in characteristics, and registered it through VCDS. About a month after that, I got the same result - after standing for about 20 hours, the battery has about 4-5 V. The battery was replaced again and again about a month later, the same problem. After that, I conducted several tests and reread a lot of information. I also contacted auto electricians who did not find any faults in my car. The leakage current is 30-40 milliamps in sleep mode. The battery voltage practically does not drop during the night. As far as I understand, the problem is that periodically one of the units comes out of sleep mode and drains the battery with a high current (more than 1 ampere). Of the constant errors, there is only one U142100 Control unit of the emergency call module and communication unit, no communication. Tell me, how can I identify the unit that drains the battery with such a rare frequency? Perhaps I can check something else? I will be happy to consider any clarifications and applications. Thanks in advance!