The largest online repair guide library for every car

About us
Contact support
FAQ
Sign up
Sign in

2020 CX-5 Battery Draining Fast - Electrical Issue?

0

Mike T. · rep 0 · May 24, 2:34 PM · 1 replies · solved · Question

Vehicle: 2020 Mazda CX-5 Grand Touring

My 2020 Mazda CX-5 Grand Touring has been having battery issues lately. Over the past few weeks, if I leave it parked for more than a day, the battery is completely dead. I've had to jump-start it multiple times, and it's getting really frustrating.

The battery itself is only about a year old, so I'm not sure if it's that or something else draining it. There aren't any warning lights on the dash, but it definitely feels like something electrical is drawing power when the car is off.

Has anyone else experienced a parasitic drain or similar battery problems with their 2020 CX-5? Any ideas on what I should check first before taking it to the dealership?

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 24, 2:34 PM

0

ClearTheCode admin answer:

It sounds like you're dealing with a parasitic battery drain, which is a common but often tricky electrical issue. Here are some steps and potential causes to investigate:

  1. Test the Battery and Charging System: Even a relatively new battery can fail. Have your battery professionally tested at an auto parts store to rule out an internal short or weak cells. While there, ask them to check your alternator's output to ensure it's charging the battery correctly when the engine is running.
  2. Perform a Parasitic Draw Test:
    • Ensure all accessories are off, doors are closed, and the vehicle is locked (as if you were leaving it overnight).
    • Disconnect the negative battery terminal.
    • Connect a multimeter in series between the negative battery post and the disconnected negative terminal. Set the multimeter to measure amps (A).
    • Wait at least 15-30 minutes for all vehicle modules to 'go to sleep.' A normal draw should typically be under 50 milliamps (0.05A). If it's significantly higher, you have a drain.
  3. Isolate the Circuit: If a high draw is detected, start pulling fuses one by one from the fuse box (both under the hood and inside the cabin), observing the multimeter. When the amperage drops significantly, you've found the circuit responsible for the drain.
  4. Common Culprits for Parasitic Drains:
    • Aftermarket Accessories: Anything added to the vehicle (stereo, alarm, dash cam) can sometimes cause a drain if wired improperly.
    • Faulty Modules: Infotainment systems, body control modules (BCM), or even a navigation unit can sometimes fail and remain active when the car is off.
    • Sticking Relays: A relay that doesn't fully disengage can keep a circuit powered.
    • Lights: Glove box, trunk, or vanity mirror lights staying on due to a faulty switch.

OBD Codes: While a parasitic drain itself doesn't usually trigger a direct OBD-II code, the faulty module causing the drain might have stored diagnostic trouble codes (DTCs). Using an OBD-II scanner to check for any stored or pending codes in all modules (not just the engine) can provide clues.

When to See a Shop: If you're uncomfortable performing the multimeter test, can't isolate the draining circuit, or suspect a complex module failure, it's best to take your 2020 Mazda CX-5 to a qualified Mazda technician. They have specialized diagnostic tools and expertise to efficiently pinpoint and repair the exact source of the electrical drain.

Menu

Help & account