U15AC on 2021 Audi e-tron — Signal Damping Log - Malfunction
1 vehicles · 1 makes
Most Reported On
U15AC is an OBD-II diagnostic trouble code meaning “Signal Damping Log - Malfunction.” A charger-internal diagnostic fault relating to the signal damping log used by the powerline communication (PLC) path in the charging system. Audi lists DTC U15AC00 ("Signal damping log malfunction", also rendered "Signal damping log fault") in TSBs 2061788 and 2062631 as one of the codes stored in high-voltage battery charger J1050 on 2020-2021 e-tron quattro and e-tron Sportback. Audi explicitly attributes these entries to a diagnosis issue in the onboard-charger software (levels 0070/0079/0081/0088) - they are documented "ghost" DTCs, not evidence of failed charging hardware. This code is most commonly reported on 2021 Audi e-tron.
Common Causes
Diagnostic Tools
U15AC does not use the standard P/B/C/U prefix. It may be a manufacturer-specific code, so verify that a scanner supports your exact year, model and module before buying.
FAQ
What does U15AC mean?
U15AC stands for "Signal Damping Log - Malfunction." A charger-internal diagnostic fault relating to the signal damping log used by the powerline communication (PLC) path in the charging system. Audi lists DTC U15AC00 ("Signal damping log malfunction", also rendered "Signal damping log fault") in TSBs 2061788 and 2062631 as one of the codes stored in high-voltage battery charger J1050 on 2020-2021 e-tron quattro and e-tron Sportback. Audi explicitly attributes these entries to a diagnosis issue in the onboard-charger software (levels 0070/0079/0081/0088) - they are documented "ghost" DTCs, not evidence of failed charging hardware.
What are the most common causes of U15AC?
The most common causes of U15AC are: Onboard-charger software diagnosis fault - Audi's documented remedy is the OBC software update via SVM (TSB 2062631), Communication signal degradation on the DC charging PLC path, Charging station-side communication quality issue. The specific cause varies by vehicle.
How much does it cost to fix U15AC?
Repair costs vary widely depending on the root cause and vehicle.
Which vehicles are affected by U15AC?
Au7o has documented U15AC across 1 vehicle models from 1 manufacturers: Audi.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.