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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Mazda CX-9 Grand Touring 2016
A voltmeter's voltage readings can help convince the dealership that you have a problem, and helps you know when the lazy bums have actually fixed it. You can note the voltage when you first start the car...or try to start it...each day. The rate of drop off of the voltage is a big clue. Does the accessory function energize the electrical outlet? If so, don't start the engine. Without your foot on the brake pedal, push the start button. That's the accessory function. Everything else off (radio, etc.) note the voltage reading. Now start the engine and go about your business.

k9 needs to have a heart-to-heart talk with the manager of the service department. The actual service manager, not just one of the service writers. The answer they gave you is total B.S. As Youri says about that technical service bulletin, something changed after October, 2019. They used different components, or parts from a different supplier, something, that malfunctions and draws down the battery. It can be fixed. It must be fixed. Or they must buy the car back.

A TSB technical service bulletin is not a recall. It is a report telling how to identify and repair certain problems.
 
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CX9
I have to agree that the dealership's response is unsatisfactory. My 2019 CX-9 GT (built prior to October) sits for 3-4 weeks at a time (I'm retired) without being started and has no problems. They owe you a better explanation.
 

singlemalt_18

My Way IS the Highway
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2018 CX-9 Signature Silver & 2007 CX-7 GT AWD Liq Platinum
My 2018 Sig has sat idle for weeks at a time without being started or moved and I haven't had any problems; for the new models, it certainly seems to be a issue with the tailgate foot sensor. I assume that is what the TSB addresses.
 
Update.. My dealer replaced the tail gate module last week (under warranty). Have not had any issues with battery drain since, tho its only been a week. Will update this thread if battery dies again.
 

GT4GT

2020 AWD GT, 2008 FWD GT
I purchased my 2020 CX-9 GT within days of the original post. Other than driving it home and moving it in and out of the garage to install some things, I didn't drive it much. On the second night, I was playing around with the all the car's Infotainment features for about 45 to 60 minutes and the battery drained to a dangerously low level. The lights were working but the Infotainment became disabled. The car would not start. I hooked it up to a battery tender for 24 hours and that fixed the problem.

I've now been driving the car every few days for 3 weeks. So far, no signs of low battery but will have the TSB checked out by the dealer in a few weeks.
 
I purchased my 2020 CX-9 GT within days of the original post. Other than driving it home and moving it in and out of the garage to install some things, I didn't drive it much. On the second night, I was playing around with the all the car's Infotainment features for about 45 to 60 minutes and the battery drained to a dangerously low level. The lights were working but the Infotainment became disabled. The car would not start. I hooked it up to a battery tender for 24 hours and that fixed the problem.

I've now been driving the car every few days for 3 weeks. So far, no signs of low battery but will have the TSB checked out by the dealer in a few weeks.
GT4GT - when was the month/year of manufacture for your car?

You can find it on the driver side door.
 
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.
So the dealer acknowledged that your rear tailgate is pulling power and suggested you drive your car more frequently rather than actually repair the problem? Was your vehicle properly diagnosed by your dealer or do they suspect the tailgate is drawing power based simply on your description of the problem and their service experience?
 

GT4GT

2020 AWD GT, 2008 FWD GT
GT4GT - when was the month/year of manufacture for your car?

You can find it on the driver side door.
The manufacture date was 11/19.

It happened again. Tonight I was installing seat covers. I had the car radio playing and dome lights on for 45 minutes. I did not fiddle with any controls. The headlights were off. At the end of that, I could not start the car.
 
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2010 CX-9 GT
The manufacture date was 11/19.

It happened again. Tonight I was installing seat covers. I had the car radio playing and dome lights on for 45 minutes. I did not fiddle with any controls. The headlights were off. At the end of that, I could not start the car.
You need to keep taking it back to the dealer until they fix it or you meet the lemon law criteria in your state. I'd print out that TSB number and give it to the service writer. Having to start the car every couple of days to charge the battery is clearly not normal or acceptable. A call to the Mazda regional manager may also be in order.
 
I had this same mysterious parasitic draw problem causing a dead battery with my 2020 CX 5 Signature back in early April. I must have been among the first owners to report the issue. It took several weeks to sort things out. My dealer consulted with Mazda tech support and the issue was resolved by replacing the rear lift gate control module. The battery problem has not recurred since. The rear lift gate control unit part number is KBG6626H0C. The part number for the original and the new replacement is the same, however the replacement has a white paint dot in the upper right corner to distinguish it. The problem affects certain CX 9s as well as the CX 5. A TSB initially issued on 4/30/20 was recently updated with the VINs of affected CX 9 and CX 5 vehicles.
 

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A TSB initially issued on 4/30/20 was recently updated with the VINs of affected CX 9 and CX 5 vehicles.
Thanks for that valuable info. So, theoretically, Mazda has identified the vehicles by VIN that have that defective part and only need to check your vehicle's VIN against that list?
 
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Mazda CX-9 Grand Touring 2016
Apparently the manufacturer of this module either produced defective parts or parts with a bad design. And, apparently, Mazda has identified the production run of bad modules. Mazda Motor Corp. really needs to send notification to every owner of cars with this group of modules, but maybe they first need to get an adequate supply of good modules in the warehouses and dealerships.
 
Thanks for that valuable info. So, theoretically, Mazda has identified the vehicles by VIN that have that defective part and only need to check your vehicle's VIN against that list?
Yes, you just need to check to see if your VIN is among those that are affected. If your vehicle has the parasitic draw / dead battery issue and you’re VIN is not on the TSB let your dealer know. They only discovered this in April and I had to push my dealer to elevate it to get Mazda to acknowledge the problem. They may still be learning the extent of it.
 
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