Battery issues with 2019 CX-5

Sorry if this has been discussed to death. I'm not too familiar with forums (or cars) but I'm at my wits end.

My Mazda constantly seems to be having battery issues/issues related to battery. I have only had it since the end of 2021. It had one owner before me and really low kms (12k ish). Within a couple of months, the rear hatch stopped opening. Read online somewhere that if I disconnected and reconnected the negative post of the battery for a few minutes, it would fix it, and it did. That's happened several more times over the years.

It feels like I'm constantly having to replace my keyfob battery. It frequently tells me my key fob battery is low. But not consistently. It'll say it once, but after I start it, that won't happen again for a few days/weeks/months. I don't think I've ever had to replace a keyfob battery in my life before owning a mazda. I find I can go weeks without replacing it after it starts intermittently telling me it's low. Usually I don't replace it unless I get the error twice in a short time period. Mazda owed me a second key fob so I finally got that a couple of months ago. When the technician was setting up the key, he noticed that my battery was draining significantly and mentioned it to me. I told him about the other issues I'd been having and he said all of it could be a result of an old battery (my rear hatch actually wasn't working at the time as well). So I went and got a new battery that same day, and paid for the second best one they had. Somehow that didn't fix my rear hatch even though usually disconnecting/reconnecting the battery has been the fix. On top of that, it didn't seem to affect how often my car randomly tells me the key fob battery is low.

Also, maybe unrelated, but if I don't drive my car for a couple of days my brakes are so seized that I have to use all my strength to press the brake enough to start it.

I've really never had a vehicle with issues at all before, and this is my first "new" vehicle, so it's pretty disappointing, cos I've wanted a Mazda SUV ever since we rented one back in 2017. Now after perusing this forum it looks like Mazda's are rife with issues like this that have no actual solution.
 
Curious, what type of battery did you buy and do you know if the car has any history on it from before you owned it?

On the key, I've been driving these cars since 2017 (this is my third one) and I only get low battery messages when my key is in battery saver mode. You would know it because you have to hold it near the start button.
 
Has it thrown any ecu codes? Has anyone (like a dealer!) tried to diagnose the issue?
 
Read a story here by someone else.
The prior owner installed a device that kept draining battery.
The new owner did not know about it.
Something to check.
 
There was a problem with the rear hatch draining the battery. Not sure what year but this forum has a search feature that you can use.
Also, ceric brings up a good point about an aftermarket device draining battery. You need to do a little checking and see if there's anything connected that could be causing the problem.
You also need to have the car battery checked with a load test. If it's the original battery it's probably due to be replaced.
 
Rear power lift gate module IIRC was a problem on some of the 2020 draining battery. If you installed a new battery and still having issues, might need to have a mechanic check / run down parasitic draw.

Change your key fob battery next time to a 2032 model instead of the listed 2025 and that'll be the end of that problem. (It's .7mm thicker and the little internal cover doesn't close but the key fob itself will still snap together)

As far as the stuff brake pedal at start, do you have the normally aspirated engine or the turbo? I think the turbo has some type of electric brake boost. (Just saying that this could be related to your battery issues) .

Mazda's being rife with issues? 🤷‍♂️ Probably less than many brands. You've gotta remember, forums are a magnet for people with problems. I have a 2019 2.2 diesel signature with 95k flawless miles on it even though "forums" are all doom and gloom about it. My brother's 2019 turbo gas signature has been flawless as well. All of our Mazda 3's have been flawless (a 2015 touring hb, and two 2018 gt hatches) .
 
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Sorry if this has been discussed to death. I'm not too familiar with forums (or cars) but I'm at my wits end.

My Mazda constantly seems to be having battery issues/issues related to battery. I have only had it since the end of 2021. It had one owner before me and really low kms (12k ish). Within a couple of months, the rear hatch stopped opening. Read online somewhere that if I disconnected and reconnected the negative post of the battery for a few minutes, it would fix it, and it did. That's happened several more times over the years.

It feels like I'm constantly having to replace my keyfob battery. It frequently tells me my key fob battery is low. But not consistently. It'll say it once, but after I start it, that won't happen again for a few days/weeks/months. I don't think I've ever had to replace a keyfob battery in my life before owning a mazda. I find I can go weeks without replacing it after it starts intermittently telling me it's low. Usually I don't replace it unless I get the error twice in a short time period. Mazda owed me a second key fob so I finally got that a couple of months ago. When the technician was setting up the key, he noticed that my battery was draining significantly and mentioned it to me. I told him about the other issues I'd been having and he said all of it could be a result of an old battery (my rear hatch actually wasn't working at the time as well). So I went and got a new battery that same day, and paid for the second best one they had. Somehow that didn't fix my rear hatch even though usually disconnecting/reconnecting the battery has been the fix. On top of that, it didn't seem to affect how often my car randomly tells me the key fob battery is low.

Also, maybe unrelated, but if I don't drive my car for a couple of days my brakes are so seized that I have to use all my strength to press the brake enough to start it.

I've really never had a vehicle with issues at all before, and this is my first "new" vehicle, so it's pretty disappointing, cos I've wanted a Mazda SUV ever since we rented one back in 2017. Now after perusing this forum it looks like Mazda's are rife with issues like this that have no actual solution.


First ever post...

Post a complete description of your car, please.

How far away from your car do you keep your key fob at night? There is supposition that the car and fob keep communicating, draining the battery.

You have deadly issues with the brakes, but haven't immediately gone to a dealer? Why?
 
First ever post...

Post a complete description of your car, please.

How far away from your car do you keep your key fob at night? There is supposition that the car and fob keep communicating, draining the battery.

You have deadly issues with the brakes, but haven't immediately gone to a dealer? Why?

What else do you need to know? It's a 2019 CX-5 Touring.

My car is in my detached garage and my keyfob is probably about 20 feet away inside my house.

I have taken it to mazda and another mechanic. Both told me if the negative battery post fix works then that's cheaper than replacing parts. The dealership told me it's normal for the brakes to be somewhat seized after sitting in disuse for more than 24 hours and made it sound uncertain as to whether there was any solution, so I didn't want to spend hundreds and lose my car for a day for something they didn't know how to fix. What about the brakes being seized is "deadly"? Maybe my terminology is off.
 
Rear power lift gate module IIRC was a problem on some of the 2020 draining battery. If you installed a new battery and still having issues, might need to have a mechanic check / run down parasitic draw.

Change your key fob battery next time to a 2032 model instead of the listed 2025 and that'll be the end of that problem. (It's .7mm thicker and the little internal cover doesn't close but the key fob itself will still snap together)

As far as the stuff brake pedal at start, do you have the normally aspirated engine or the turbo? I think the turbo has some type of electric brake boost. (Just saying that this could be related to your battery issues) .

Mazda's being rife with issues? 🤷‍♂️ Probably less than many brands. You've gotta remember, forums are a magnet for people with problems. I have a 2019 2.2 diesel signature with 95k flawless miles on it even though "forums" are all doom and gloom about it. My brother's 2019 turbo gas signature has been flawless as well. All of our Mazda 3's have been flawless (a 2015 touring hb, and two 2018 gt hatches) .
No turbo. I'll try the 2032 battery.
 
Remote start.
I do have a remote start, but it's a borderline necessity in the prairies in Canada. I've had remote starts on every car I've had and have never had battery issues from it. Maybe a parasitic draw, but never actual problems arising from it.
 
Has it thrown any ecu codes? Has anyone (like a dealer!) tried to diagnose the issue?
I have taken it to the dealer. As far as the rear hatch they told me if disconnecting/reconnecting the battery works then that's a cheaper solution than replacing parts. As far as the brakes they told me it's normal.
 
Curious, what type of battery did you buy and do you know if the car has any history on it from before you owned it?

On the key, I've been driving these cars since 2017 (this is my third one) and I only get low battery messages when my key is in battery saver mode. You would know it because you have to hold it near the start button.
It is a Motomaster 640CCA.

The fobs go into battery saver mode? My dash just tells me the battery is low and to hold it near the start button, but occasionally I can't unlock my door with it either. And a few times it's happened after I've already driven my car that day.
 
It is a Motomaster 640CCA.

The fobs go into battery saver mode? My dash just tells me the battery is low and to hold it near the start button, but occasionally I can't unlock my door with it either. And a few times it's happened after I've already driven my car that day.
Make sure it is not in battery saver mode by pressing lock on the key 4 times, then holding lock for 1.5 seconds. This toggles its ability to transmit.
 
I was having similar fob issues with my 2020 GT, fixed by using name brand (Duracel) battery in fob instead of cheapo off brand purchased on internet.
 
The "Mazda's are rife with issues" comment cracks me up. I had a 2019 GT from 19-21 and never had an issue. I have had my '21 GTR since May of 21 and also have had no issues other than shuddering brakes. Very reliable cars. I would definitely consider having the rear hatch module replaced and see if it fixes the issue. Maybe you could swap it yourself with the TSB instructions? Also, maybe try another dealer if you have that option.
 
Mazda's being rife with issues? 🤷‍♂️ Probably less than many brands. You've gotta remember, forums are a magnet for people with problems. I have a 2019 2.2 diesel signature with 95k flawless miles on it even though "forums" are all doom and gloom about it. My brother's 2019 turbo gas signature has been flawless as well. All of our Mazda 3's have been flawless (a 2015 touring hb, and two 2018 gt hatches) .
You got that right. Just like the dragging rear calipers on the 2016's. I've had my 16 for 8+ years now and never a problem with the rear brakes. Actually never had any problems at all.
Also our 19 GTR is rock solid.
Doom & Gloom.
 
The dealership told me it's normal for the brakes to be somewhat seized after sitting in disuse for more than 24 hours and made it sound uncertain as to whether there was any solution, so I didn't want to spend hundreds and lose my car for a day for something they didn't know how to fix. What about the brakes being seized is "deadly"? Maybe my terminology is off.

My car can sit for up to a month. The brakes are as perfect as when I last drove it.

You have a *problem* with your brakes. That means they can *fail*. *Deadly*.

The key fob communicates with the car. People have said that if the key is too close to the car at night, that the car computer stays away, using power.
 
⋯ I would definitely consider having the rear hatch module replaced and see if it fixes the issue. Maybe you could swap it yourself with the TSB instructions? Also, maybe try another dealer if you have that option.
The Special Service Program (SSP) C2 for battery drained-out problem caused by poor software logic in power liftgate control unit is for 2020 CX-5 and 2019~2020 CX-9. OP’s 2019 CX-5 isn’t affected. And his visit to the Mazda dealer would result the automatic replacement of the control unit under the SSP C2 if his 2019 CX-5 qualifies.

Mazda CX-5 Special Service Program (SSP) C2

Honestly nothing described by OP indicates there’s a parasitic draw or battery drain-out problem to me.
 
My car can sit for up to a month. The brakes are as perfect as when I last drove it.

You have a *problem* with your brakes. That means they can *fail*. *Deadly*.

The key fob communicates with the car. People have said that if the key is too close to the car at night, that the car computer stays away, using power.
I had the same brake problem the first couple of years into the life of my 2019. Maybe not quite as bad as the OP but there were a couple times it was difficult to get the green light to come on the start button. It only did it after sitting all night. You just had to push the brake pedal extremely hard.
It did not affect braking and it was not deadly. It eventually went away. Sounds like the same problem the OP is having. Could be hydraulics, air, whatever.
 

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