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Battery Drain Issues - 2016 Audi A4 Quattro Premium Plus

0

Mike T. · rep 0 · May 25, 3:14 AM · 1 replies · solved · Question

Vehicle: 2016 Audi A4 Quattro Premium Plus

Hi all,

I'm having a persistent problem with my 2016 Audi A4 Quattro Premium Plus. The battery keeps dying, sometimes overnight, sometimes after just a couple of days of not driving it. I've replaced the battery twice in the last year, thinking it was just a bad battery, but the issue keeps coming back.

I've noticed that sometimes the interior lights stay on for too long, or I hear a faint humming sound even after locking the car. I'm worried there's a parasitic draw somewhere, but I'm not sure where to even begin looking. It's incredibly frustrating to wake up to a dead car, especially when I need to get to work.

Has anyone else dealt with a similar battery drain on their A4? What was the culprit? Any advice on how to track down the source of the drain would be greatly appreciated!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 3:14 AM

0

ClearTheCode admin answer:

Parasitic battery drains are one of the most challenging electrical issues to diagnose, especially in modern Audis with their complex electrical systems. Here's how to approach it:

Troubleshooting Steps:

  1. Measure Parasitic Draw: You'll need a multimeter capable of measuring amperage. Connect it in series with the negative battery terminal. Close all doors, ensure all lights are off, and let the car 'go to sleep' (this can take 20-60 minutes). A normal draw is usually under 50 mA (0.05 Amps). If it's significantly higher, you have a drain.
  2. Fuse Pull Test: Once you've confirmed a high draw, start pulling fuses one by one from both interior and engine bay fuse boxes. Watch the multimeter; when the amperage drops significantly, you've found the circuit causing the draw.
  3. Module Isolation: If a fuse points to a specific system (e.g., MMI, comfort control, door modules), you may need to further isolate components within that system.

Common Causes:

  • Faulty Control Modules: Many modules (e.g., MMI, comfort control, gateway, telematics) can fail internally and remain 'awake' or draw excessive current even when the car is off. OBD codes like B100000 - Control Module - Faulty or specific communication errors can sometimes point to these.
  • Aftermarket Accessories: Improperly installed aftermarket stereos, alarms, dash cams, or remote starters are common culprits.
  • Stuck Relays: A relay that doesn't de-energize can keep a circuit active.
  • Lighting Issues: Trunk lights, glove box lights, or vanity mirror lights that don't turn off completely.
  • Door Lock Actuators: A faulty door lock mechanism or microswitch can prevent the car from entering sleep mode.

When to See a Shop:

If you're uncomfortable performing electrical tests, or if the fuse pull test doesn't clearly identify the source, it's best to take your A4 to an Audi specialist. They have advanced diagnostic equipment to pinpoint the exact module or component causing the draw, often using thermal imaging or specialized current clamps to find the 'hot' spot. A persistent parasitic draw can damage new batteries and other electrical components over time.

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