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Mystery Battery Drain on my 2017 LaCrosse Premium

0

Mike T. · rep 0 · May 25, 2:48 AM · 1 replies · solved · Question

Vehicle: 2017 Buick LaCrosse Premium

I'm having a persistent issue with my 2017 Buick LaCrosse Premium where the battery keeps draining overnight or after sitting for a couple of days. I've replaced the battery twice in the last year, thinking it was just a bad battery, but the problem persists. It's incredibly frustrating to wake up to a dead car.

I've checked for obvious things like lights left on, but can't find anything. Could it be a parasitic draw from a module or something electrical? What's the best way to track down a phantom drain like this?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 2:48 AM

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  1. Understand Parasitic Draw: A parasitic draw is when electrical components continue to draw power from the battery even when the vehicle is turned off. All modern cars have some level of parasitic draw for things like the clock and computer memory, but an excessive draw will drain the battery quickly.
  2. Perform a Parasitic Draw Test: This is best done with a multimeter. Connect the multimeter in series between the negative battery terminal and the negative battery cable. With the car off and all doors closed (allowing modules to "sleep"), observe the amperage reading. A healthy draw is typically under 50 milliamps (0.05 amps). Anything significantly higher indicates a problem.
  3. Identify the Culprit Circuit: Once an excessive draw is confirmed, the next step is to systematically pull fuses, one by one, while monitoring the multimeter. When the amperage drops significantly after pulling a specific fuse, you've identified the circuit where the draw originates. Common culprits include the infotainment system, OnStar module, body control module (BCM), glove box lights, or aftermarket accessories.
  4. Check for Faulty Modules: Sometimes, a module fails to "sleep" properly, continuously drawing power. This could be due to internal faults or software glitches. A diagnostic scan tool can sometimes identify modules that are not shutting down correctly.
  5. When to See a Shop: Tracking down an intermittent parasitic draw can be time-consuming and requires patience and electrical knowledge. If you're not comfortable with multimeter testing and fuse pulling, or if the draw is difficult to pinpoint, it's best to consult a professional automotive electrician or a Buick dealership. They have specialized diagnostic equipment and experience with these types of issues. While there may not be specific OBD-II codes for a battery drain, related electrical issues could trigger codes like U0100 (Lost Communication with ECM/PCM) or B1325 (Device Power Circuit Fault) if a module is failing or losing power intermittently.
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