Writer and philosopher George Santayana wrote, “Those who cannot remember the past are condemned to repeat it.” This can apply to many things these days, but in this case it’s a class action lawsuit against Subaru for batteries that won’t hold a charge. According to CarComplaints.com, the problem isn’t the batteries themselves, but a parasitic drain that continues to draw power from the battery even when the car is turned off.
Electrical system defects reportedly fail to correctly manage power consumption when a vehicle is shut off. The plaintiffs claim at least one electronic control module fails to put the vehicle into a low power sleep mode which allows the parasitic battery drain. This can manifest out of nowhere and leave the battery too weak to function before it finally dies.
This lawsuit covers almost every model Subaru has on sale:
- 2021-2022 Subaru Outback
- 2021-2024 Subaru Forester
- 2021-2023 Subaru Legacy
- 2021-2023 Subaru WRX
- 2021-2022 Subaru Ascent
- 2019-2023 Subaru Crosstrek
- 2019-2024 Subaru Crosstrek Hybrid
- 2022-2025 Subaru Forester Wilderness
- 2019-2023 Subaru Impreza
In each of these cases, the problem was initially diagnosed as a dead battery, but problems persist even with a replacement because the power drain issue keeps killing the battery, including replacements. Subaru has issued a service information bulletin with the proper diagnostic procedures to follow rather than assuming the problem lies in the Data Communication Module (DCM). There does not appear to be a standard known cure for these issues at this time.
History repeating
The reason Subaru techs tend to assume a faulty DCM is causing the power drain goes back to an earlier class action lawsuit for the same behavior on older models. This was one of the side effects of shutting down the cellular 3G network, which was how many cars provided features and connectivity at the time. Subaru’s Starlink system (which has nothing to do with Elon Musk’s satellite network of the same name) was one of them, and the excessive power drain comes from its constant attempts to connect to the 3G network that no longer exists. According to The Autopian, Subaru granted an extended warranty of the DCM, including its removal or replacement in cars diagnosed with this problem. This is why Subaru techs needed the guidance to actually look for the problem instead of assuming it’s another DCM issue, because newer DCMs don’t have this problem.
Having already gone through one significant power drain issue, one might think that Subaru would make an effort to avoid similar issues in future vehicles. Unfortunately, that doesn’t seem to be the case, and unlike the DCM there is no specific known cause of these latest problems. As the great Shirley Bassey sang, “It’s all just a little bit of history repeating.”
