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Persistent Battery Drain on my 2017 MKZ Reserve - Driving me crazy!

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Mike T. · rep 0 · May 25, 4:30 AM · 1 replies · solved · Question

Vehicle: 2017 Lincoln MKZ Reserve

Hey everyone,

I'm having a really frustrating issue with my 2017 Lincoln MKZ Reserve. For the past few weeks, if I leave it parked for more than a day or two, the battery is completely dead. I've had the battery tested at AutoZone, and they say it's good, but it just keeps dying.

I've tried charging it up, and it starts fine, but the problem always comes back. It's getting really annoying having to jump-start it all the time. Has anyone experienced a parasitic draw on their MKZ or other Lincoln models? What should I be looking for?

Any tips on how to diagnose this myself before I take it to the dealer would be greatly appreciated. Thanks!

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 4:30 AM

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ClearTheCode admin answer:

A persistent battery drain, or parasitic draw, is a common issue that can be tricky to diagnose. It means something is drawing power even when the car is off. Here's how to approach it:

Diagnosis Steps:

  1. Confirm the Draw: Fully charge your battery. 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 (A). A normal draw should be under 50 milliamps (0.05A) after about 30 minutes (allowing modules to 'go to sleep'). If it's higher, you have a draw.
  2. Fuse Pull Method: With the multimeter still connected and showing a high draw, start pulling fuses one by one from the fuse box (both under the hood and inside the cabin). Watch the multimeter. When the amperage drops significantly, you've found the circuit responsible.
  3. Identify the Component: Once you've isolated the circuit, consult your owner's manual or a service diagram to see which components are on that circuit. Common culprits include:
    • SYNC/Infotainment system (APIM module)
    • Door lock actuators or modules
    • Glove box or trunk lights staying on
    • Aftermarket accessories (dash cams, remote starters)
    • Faulty body control module (BCM)

Common Causes for Lincoln MKZ:

  • SYNC 3 Module (APIM): Sometimes it doesn't fully shut down.
  • Door Ajar Switches: A faulty switch can trick the car into thinking a door is open, keeping modules awake.
  • Faulty Relays: A relay stuck in the 'on' position can power a component continuously.

When to See a Shop:

If you're uncomfortable with electrical testing or can't locate the source after trying the fuse pull method, it's best to take your 2017 Lincoln MKZ to a qualified technician. They have specialized diagnostic tools that can pinpoint the exact module causing the draw, especially if it's an internal module fault or complex wiring issue. They can also check for any relevant diagnostic trouble codes (DTCs), though parasitic draws don't always trigger specific OBD-II codes directly related to the draw itself, but rather low voltage codes like P0562 (System Voltage Low).

Addressing this promptly will prevent premature battery wear and ensure reliable starting.

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