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2020 Crosstrek Battery Draining Overnight - Parasitic Draw?

0

Mike T. · rep 0 · May 25, 2:19 AM · 1 replies · solved · Question

Vehicle: 2020 Subaru Crosstrek Limited

Hey everyone,

I'm having a persistent problem with my 2020 Subaru Crosstrek Limited. The battery keeps dying, sometimes overnight, sometimes after sitting for just a couple of days. I've already replaced the battery once, thinking it was just old, but the new one is doing the same thing. It's incredibly frustrating to wake up to a dead car.

I've made sure all lights are off, doors are closed, and nothing is plugged into the charging ports. Could this be a parasitic draw? I've heard about issues with the Starlink system or Eyesight draining batteries on newer Subarus. Has anyone else experienced this, and what was the fix?

Any tips on how to diagnose this myself before taking it to the dealer would be greatly appreciated!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 2:19 AM

0

ClearTheCode admin answer:

It sounds like you're dealing with a parasitic battery drain, which is a common and frustrating issue, especially with modern vehicles that have numerous electronic modules constantly drawing power. Your suspicion about Starlink or Eyesight is valid, as these systems can sometimes be culprits.

Here's how to approach diagnosing and resolving the issue:

  1. Common Causes for Subaru Battery Drains:

    • Starlink DCM (Data Communication Module): This module, responsible for telematics services, can sometimes fail to enter sleep mode, continuously drawing power. Subaru has issued TSBs and software updates for this.
    • Eyesight System: While less common, a faulty Eyesight component or its associated wiring could cause a drain.
    • Aftermarket Accessories: Anything added to the vehicle (dash cams, remote starters, audio systems) that's not properly wired can cause a drain.
    • Faulty Relays or Fuses: A 'stuck' relay or a short in a circuit can keep components powered on.
    • Infotainment System Glitches: The head unit itself can sometimes stay partially awake.

  2. Basic DIY Diagnostic Steps (Parasitic Draw Test):

    • Tools Needed: A multimeter capable of measuring amperage (Amps).
    • Procedure:
      1. Ensure the car is off, doors closed, and hood open (latch may need to be pressed to simulate closure if it has a switch).
      2. Disconnect the negative battery terminal.
      3. Set your multimeter to measure Amps (start with a high range, like 10A or 20A, then switch down).
      4. Connect the multimeter in series between the negative battery post and the disconnected negative battery cable. (Red lead to cable, black lead to battery post).
      5. Wait for modules to 'go to sleep' (this can take 20-60 minutes). A normal parasitic draw should be around 20-50 milliamps (0.02-0.05 Amps). Anything significantly higher indicates a problem.
      6. Once you have a high reading, start pulling fuses one by one, watching the multimeter. When the current draw drops significantly, you've found the circuit with the drain.

  3. When to See a Shop:

    • If you're uncomfortable performing the parasitic draw test yourself, or if you identify a circuit but can't pinpoint the specific component (e.g., the 'Radio' fuse drops the draw, but you don't know if it's the head unit or the DCM), it's time to visit a dealership or a specialized auto electrical shop.
    • Subaru dealerships have specific diagnostic tools and access to TSBs related to known battery drain issues, especially concerning Starlink. They can perform software updates or replace faulty modules. While no specific OBD codes directly indicate a parasitic draw, persistent low voltage can sometimes trigger various U-codes (Network Communication) or C-codes (Chassis) if modules are not communicating correctly due to insufficient power.
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