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Battery Drain & Random Warning Lights on 2017 LaCrosse

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Mark S. · rep 0 · May 22, 3:54 AM · 1 replies · solved · Question

Vehicle: 2017 Buick LaCrosse Premium

Hello,

I'm dealing with a really annoying problem with my 2017 Buick LaCrosse Premium. The battery keeps dying, sometimes after just sitting for a couple of days. I've had to jump-start it multiple times. On top of that, I've noticed random warning lights (like ABS, StabiliTrak, or even check engine) briefly flashing on the dash, then disappearing.

I've replaced the battery once, but the problem came back. Could this be a parasitic draw, or something else electrical? Any insights from other 2017 LaCrosse owners would be greatly appreciated!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 3:54 AM

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ClearTheCode admin answer:

Battery drain combined with random warning lights on your 2017 Buick LaCrosse Premium points strongly to an underlying electrical issue. This isn't just a bad battery problem, especially since you've already replaced it. Here's what needs to be investigated:

  1. Parasitic Draw: This is the most likely culprit for a battery that dies while sitting. A parasitic draw occurs when an electrical component continues to draw power even when the vehicle is off. Common sources include:
    • Faulty infotainment modules (as mentioned in another thread).
    • Aftermarket accessories wired incorrectly.
    • Stuck relays.
    • Faulty body control module (BCM) components.
    • Glove box or trunk lights not turning off. Diagnosing a parasitic draw requires a multimeter and systematically checking circuits by pulling fuses.
  2. Alternator Output: While less likely to cause a dead battery after sitting (it would usually die while driving), a failing alternator might not be fully charging the battery. Have the alternator's output tested to ensure it's providing adequate voltage (typically 13.5-14.5 volts).
  3. Faulty Battery (Even New Ones): Though you replaced it, a new battery can sometimes be defective. Ensure the battery terminals are clean and tight.
  4. Grounding Issues: Loose or corroded ground connections can cause a myriad of electrical problems, including intermittent warning lights and poor charging.
  5. Body Control Module (BCM) or Communication Issues: The random warning lights suggest a potential issue with the BCM or the vehicle's communication network (CAN bus). Faulty modules can cause erroneous signals or remain 'awake' when they shouldn't, leading to draw. OBD-II codes related to communication issues (U-codes like U0100, U0140) might be present.

When to See a Shop: Given the complexity of diagnosing parasitic draws and intermittent electrical faults, it's highly recommended to take your LaCrosse to a qualified automotive electrician or a Buick dealership. They have the expertise and specialized tools to perform a comprehensive parasitic draw test and diagnose communication network issues. Explain all symptoms, including the specific warning lights you've seen.

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