U15AC on Audi
Signal Damping Log - Malfunction
U15AC on Audi vehicles indicates signal damping log - malfunction. Au7o has documented this code across 1 Audi model — most commonly on e-tron. 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.
Common Causes of U15AC
- •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
U15AC on Audi by Model
Audi e-tron(1 issue)
- 2021 e-tron Charging Interruptions with Onboard-Charger Software 0070 - Diagnosis Required2021
Audi TSB 2061788/2 covers model-year 2021 e-tron quattro and e-tron Sportback vehicles with specified AC/DC charging interruptions, charging-flap operation problems, or an app request for auxiliary heating that does not pre-heat the vehicle when matching DTCs are stored in high-voltage battery charger control module J1050. Audi attributes the documented condition to onboard-charger software and identifies old software level 0070, not a proven failed charger module.
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View U15AC across all makes →Frequently Asked Questions
What does U15AC mean on Audi?▼
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. On Audi specifically, this code is documented across 1 model.
What causes U15AC on Audi vehicles?▼
Common causes on Audi: 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. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix U15AC on a Audi?▼
Repair costs vary widely depending on the root cause and specific Audi model.
Which Audi models have U15AC documented?▼
Au7o has documented U15AC on 1 Audi model: e-tron.