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2019 Discovery Sport HSE - Persistent Battery Drain Mystery

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Christine P. · rep 0 · May 22, 6:32 AM · 1 replies · solved · Question

Vehicle: 2019 Land Rover Discovery Sport HSE

Hey everyone,

I'm tearing my hair out over a persistent battery drain issue on my 2019 Land Rover Discovery Sport HSE. It's been happening intermittently for the past few weeks. I'll park it overnight, and sometimes in the morning, it's completely dead, needing a jump start. Other times, it's fine for days.

I've checked all the obvious things – no lights left on, doors are shut properly, no aftermarket accessories plugged in. The battery itself is relatively new, replaced about 8 months ago, and tests show it's healthy. It just seems like something is staying awake and drawing power when it shouldn't be.

Has anyone else experienced this with their Discovery Sport or similar Land Rover models? Any specific modules or common culprits I should be looking into? It's driving me crazy not knowing if I'll be able to start my car each morning.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 6:32 AM

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ClearTheCode admin answer:

Persistent battery drain, also known as a parasitic draw, is a common and frustrating issue, especially in modern vehicles with complex electrical systems like your 2019 Land Rover Discovery Sport HSE. Pinpointing the exact cause requires systematic diagnosis.

Here are steps and common causes to consider:

  1. Perform a Parasitic Draw Test:

    • Ensure the vehicle has been off for at least 30 minutes to allow all modules to 'go to sleep.'
    • Disconnect the negative battery terminal and connect a multimeter in series between the negative battery post and the negative battery cable. Set the multimeter to measure amperage (amps).
    • A normal draw should be less than 50 milliamps (0.05 amps). If it's significantly higher, you have a draw.
    • Begin pulling fuses one by one from the fuse box (both under the hood and inside the cabin) while watching the multimeter. When the amperage drops significantly, you've identified the circuit causing the draw.

  2. Common Causes in Land Rovers:

    • Infotainment System/Telematics Module: These systems can sometimes fail to shut down completely, staying awake and drawing power. This is a frequent culprit.
    • Door Latch Modules: A faulty door latch sensor can incorrectly signal that a door is ajar, keeping modules awake.
    • HVAC Blower Motor Resistor: A failing resistor can cause the blower motor to run intermittently or stay on at a very low speed.
    • Faulty Relays: A relay that is stuck closed can keep a circuit energized.
    • Battery Monitoring System (BMS): While less common for direct drain, a faulty BMS can sometimes mismanage charging or reporting.

  3. OBD Codes: A direct OBD code for 'parasitic draw' is rare. However, if a specific module is failing and causing the draw, it might log a communication fault (e.g., a U-code like U0140 - Lost Communication With Body Control Module) or an internal fault code (B-code) related to that module.

When to See a Shop: If you're uncomfortable performing electrical diagnostics or if the draw is difficult to isolate (e.g., it's intermittent or on a complex circuit), it's best to consult a qualified Land Rover specialist or an automotive electrical shop. They have specialized diagnostic tools and experience with these complex systems to accurately identify and repair the issue.

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