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Persistent Battery Drain on my 2020 G70 - What's going on?

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Emily N. · rep 0 · May 22, 6:24 AM · 1 replies · solved · Question

Vehicle: 2020 Genesis G70 3.3T Sport

Hey everyone,

I'm having a really frustrating issue with my 2020 Genesis G70 3.3T Sport. For the past few weeks, if I leave it parked for more than a day or two, the battery is completely dead. I've had to jump-start it multiple times, and I'm worried about damaging the electrical system or the battery itself.

I've checked the obvious things like making sure all the lights are off, and nothing seems to be left on. I don't have any aftermarket accessories installed, so it's all factory. Has anyone else experienced a persistent battery drain issue with their G70, especially around the 2020 model year?

What could be causing this? Is it a known issue with a specific module or component? Any advice on what I should check or look for before taking it to the dealership would be greatly appreciated. I'm trying to figure out if this is a common reliability concern.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 6:24 AM

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ClearTheCode admin answer: A persistent battery drain, often referred to as a "parasitic draw," is a common and frustrating issue. It means something in your 2020 Genesis G70 is drawing power even when the vehicle is turned off. This can lead to premature battery failure and unreliable starting.

Here's a breakdown of potential causes and diagnostic steps:

  1. Common Causes of Parasitic Draw:

    • Infotainment System/Navigation: Software glitches or a module not properly shutting down can keep these systems partially active, consuming power.
    • Faulty Relays: A relay that sticks in the "on" position can continuously power a circuit, such as for the fuel pump or cooling fan.
    • Trunk/Glove Box Lights: A light that stays on due to a faulty switch, even if it's not immediately visible.
    • Body Control Module (BCM) Issues: The BCM controls many electrical functions; a fault here can lead to various electrical problems, including battery drain.
    • Alternator Diode Failure: A failing diode in the alternator can allow current to flow back to ground, slowly draining the battery.

  2. Initial Diagnostic Steps You Can Take:

    • Check for Visible Lights: Ensure all interior lights, trunk lights, and glove box lights are off when the doors are closed and the car is locked.
    • Perform a Parasitic Draw Test:
      • Charge your battery fully.
      • Disconnect the negative battery terminal.
      • Connect a multimeter in series between the negative battery post and the negative battery cable (set to amperage, typically 10A or 20A range). Ensure the doors are closed and the car is locked.
      • Wait for the vehicle's systems to "go to sleep" (this can take 15-30 minutes). A normal draw is usually under 50mA. If it's significantly higher, you have a draw.
      • If the draw is high, start pulling fuses one by one from the fuse box, observing the multimeter. When the draw drops significantly, you've found the circuit responsible.

  3. When to See a Professional Shop:

    • If you're uncomfortable performing electrical diagnostics yourself, as improper testing can damage electrical components.
    • If you've identified a high draw but can't pinpoint the exact component on the circuit, or if the draw is intermittent.
    • If the issue persists after basic troubleshooting, as it may indicate a more complex electrical fault or a failing module that requires specialized diagnostic tools (like a scan tool to check for fault codes related to specific modules, though direct OBD codes for parasitic draw are rare).
    • Consider checking with a Genesis dealership for any relevant Technical Service Bulletins (TSBs) or recalls related to battery drain for your 2020 G70 model. Sometimes software updates are available to address these issues.
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