2016~2021 Battery drain in 2020 Mazdas

Vertigo88, yes the 3 year/36k mile bumper to bumper warranty covers this repair. Customer service excellent so far, i dropped the car off on friday afternoon, they put me into a new CX-9, received a call this morning for update, shd be done in a few days (waiting for part to come in).
This is great news. Thanks for the update. Please keep us posted if there are any other issues.

I parked my car Saturday night and haven't driven it since. I'll try to start it up tomorrow or Wednesday to see if the battery drained again. If so, it will be going in to the shop (I probably should have taken it in for a full diagnosis already, really).
 
Hi!

I just purchased a CX-9 Signature line (2020). I had the car approximately 1 month, drove it very little due to current teleworking conditions. I drove the car on a Thursday and noticed the liftgate wouldn't open with my foot sensor. By Saturday evening the car would not start. On Sunday morning it was a completely dead battery...had to jump it :( I hadn't even made my first payment.

The dealership is telling me the same (rear tail gate is pulling power). They recommend driving the car every few days to be sure that doesn't happen, which seems unreasonable for any car yet alone one that cost $48K.

Now what? I have to drive the car everyday to keep it running? How can I be sure this is the actual problem and something else won't drain the battery? Did anyone have this problem and have a good outcome (fixed problem, no other issues)? Looking for some advice on questions for Mazda when I pick it up. My husband took the 2016 CX-5 so I could have the newer, more reliable car. Now I'm skeptical on how reliable it will be.

Thank you.
 
Alright, this concerns me now. I put money down for a 2020 CX-9 GT, so it is likely that whatever problems k9cognac had, I may experience too (knocks on wood).

@PTguy - let's say I buy a voltmeter. On the day that I pick up the car, how can I show to the dealership that this car, before I even take delivery, is draining battery, and how can I do that with a voltmeter.
 
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Ottawa, Ontario
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17 Mazda 6 GT
I just purchased a CX-9 Signature line (2020). I drove the car on a Thursday and noticed the liftgate wouldn't open with my foot sensor. By Saturday evening the car would not start. On Sunday morning it was a completely dead battery...had to jump it :( I hadn't even made my first payment.

The dealership is telling me the same (rear tail gate is pulling power). They recommend driving the car every few days to be sure that doesn't happen, which seems unreasonable for any car yet alone one that cost $48K.

Now what? I have to drive the car everyday to keep it running?
What a BS answer from the dealer. Totally unacceptable.

"You have to start and drive it every few days" is their fix?
If this was the answer they gave me for this problem, I'd blow my stack.

Reminds me of what Honda has been telling CR-V owners with the oil dilution problems: Drive the car far enough to fully warm up the engine, no matter where you're actually going.
So if I go in my CR-V to my corner store, which is one mile away, I have to take a ten mile round trip, according to Honda. Same BS. Dealers not accepting responsibility or blame.

For your battery issue: what if you go out of town for a week, or fly somewhere and leave your car at the airport? Are you supposed to hire someone to start your car every second day?
They need to find the problem and FIX IT.
Insist on nothing less.
 
What a BS answer from the dealer. Totally unacceptable.

"They need to find the problem and FIX IT.
Insist on nothing less.
Agreed. This is part of the bumper to bumper warranty. Now to play the devils advocate, every modern car draws power continuously. This is necessary for the keyless entry system to work, the remote locking, unlocking, etc, so if you leave your cars sitting duck for months, then the battery will go dead. But every few days is unreasonable, and even if you use the car once a week or one every 2 weeks it should still start without issues. Letting your car sit longer than that opens the door to a bunch of other issues anyways (Brake disc rusting out, etc). You need to request that the faulty parts be replaced, the car is still under warranty so don’t let a bad dealer turn you around.

You should never need to do this with a brand new vehicle, but if you are nervous about this issue you can buy a battery booster. they are not expensive and pretty compact nowadays and old their charge for a long time.

It is possible to self diagnose the issue, with a voltmeter, but I am not sure which voltage draw Is normal and which one is excessive. You could measure the voltage at the fuse for the rear hatch directly for a more precise evaluatio, but even then a voltage draw may be normal operation.
 
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Actually, just looked and there is a TSB out for this. No identified official fixes yet but it states that a draw higher than 65 mA 40 minutes after engine is off is abnormal. You can also see that this doesn’t seem to be an issue on CX-9 built before oct 2019. (Date of build is on a sticker in the drivers door jamb.)

If you want to test it out yourself, I would recommend popping the hood before the 40 minute wait period. Opening the door to pop the hood may reactivate some circuits and skew the results.

 
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