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2018 TLX Battery Drain Mystery - Dead Overnight!

0

Chris P. · rep 0 · May 22, 4:58 AM · 1 replies · solved · Question

Vehicle: 2018 Acura TLX A-Spec

Hey everyone,

My 2018 Acura TLX A-Spec has developed a really frustrating issue. For the past few weeks, if I leave it parked for more than 12-18 hours, the battery is completely dead. I've had the battery tested at AutoZone, and they say it's good, and the alternator is charging fine.

I'm suspecting a parasitic draw somewhere, but I'm not sure where to even begin looking. Has anyone experienced this with their 2018 TLX or similar Acura models? Any common culprits for electrical drains?

It's getting really annoying having to jump-start it every other day. Any advice would be greatly appreciated!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 22, 4:58 AM

0

ClearTheCode admin answer:

Parasitic battery drains can be tricky to diagnose but are often caused by a module not 'sleeping' properly or a short circuit. Given your battery and alternator tested good, a parasitic draw is highly likely.

Steps to Diagnose:

  1. Perform a Parasitic Draw Test: With the car off and all doors closed (simulate closed with latches if needed), disconnect the negative battery terminal. Connect a multimeter in series between the negative battery post and the negative battery cable. Set the multimeter to measure amps. A normal draw is typically under 50mA (0.05A) after all modules have gone to sleep (can take up to 30-60 minutes).
  2. Isolate the Circuit: If the draw is high, start pulling fuses one by one from the under-hood and interior fuse boxes while monitoring the multimeter. When the amperage drops significantly, you've found the circuit causing the draw.
  3. Common Culprits: For Acura TLX models, common culprits can include the HandsFreeLink (Bluetooth) module, infotainment system components, a faulty door lock actuator, or even a trunk light staying on. Sometimes, aftermarket accessories can also cause this.

Causes:

  • Faulty control module (e.g., HFL, audio unit, body control module).
  • Stuck relay (e.g., accessory relay).
  • Short circuit in a wiring harness.
  • Aftermarket electronics incorrectly wired.

When to See a Shop: If you're uncomfortable performing electrical tests or cannot isolate the circuit, it's best to take your 2018 Acura TLX to a qualified automotive electrical specialist or an Acura dealership. They have specialized diagnostic tools (like a scan tool to check for active modules or fault codes related to power management) and experience with complex electrical systems to pinpoint the exact source of the draw efficiently. Ignoring a parasitic draw can lead to premature battery failure and potential damage to other electrical components.

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