Why do I have to jump my car every day now… even though the battery is good?

I have a 2021 Ford Explorer, and I had the battery tested by AutoZone – it shows as still being good. But a friend told me there could be a different battery under the car for the Auto Start/Stop feature (the little A with the circle). I hate that feature and turn it off every day, but now I’m wondering if that’s causing the issue.

Here’s the thing: my car starts, but the engine won’t turn over. The screen shows messages like ‘Full Accessory Power Mode’ and ‘Check Brake System,’ and the Engine Start/Stop button just blinks green. But, if I jump it, everything works fine. The problem is that I have to jump it every single day. Has anyone dealt with something like this? Is there a fix? The dealer can’t see me for another two weeks, according to Ford Pass Service. Thanks in advance!

I had the same issue with my 2020. One day it was fine, the next day it wouldn’t start. I had to jump it every time, but after replacing the battery, it was fine. It only costs about $300, and the new battery should last you 4-5 years. These cars sometimes show random errors on the dashboard when the battery is dying.

@Zayden
I had a similar experience with my 2015 Ford Escape. The battery tested fine, but it needed to be replaced. I even upgraded to a larger AGM battery, and now I have no issues at all. In my new 2023 Explorer, it came with an AGM battery because of the auto start/stop. If that battery fails in a few years, I’ll just replace it too.

My mom had the same problem with her 2020 Explorer. The dealer and other auto stores tested the battery, but it still wasn’t starting right. After some frustration, I decided to buy and install a new battery myself. All the problems disappeared right after that.

I don’t think regular Ford vehicles have a secondary battery. Some models from other manufacturers, like Jeeps and some GM vehicles, do have smaller backup batteries though.

@Nico
Yeah, there’s no secondary battery in these models. Some cars have a Battery Management System (BMS) that can act up, but more often it’s just that the battery isn’t providing enough power.

@Nico
Oh, that’s good to know! I was surprised at the idea of having two batteries in my car. Sounds like I might need to replace the battery after all. Very thoughtful of you to help your parents!

There’s a fast battery test and a slow one. When AutoZone tested it, did they test the battery under load? Like with the headlights and wipers on? Sometimes a good alternator can hide a bad battery.

Vic said:
There’s a fast battery test and a slow one. When AutoZone tested it, did they test the battery under load? Like with the headlights and wipers on? Sometimes a good alternator can hide a bad battery.

Oh, that’s interesting! The test slip said ‘Battery Test,’ ‘Starting System Test,’ and ‘Charging System Test,’ all of which said ‘Good.’ The car was off when they checked it, and I didn’t have the lights or wipers on.

My newer car batteries seem to only last about 3 years. I’d suggest calling to see if they can fit you in earlier. You could also get something like a NOCO jump pack – I carry one now and check its charge every month. It’s also handy as a power block for phones at get-togethers. One time, I had an issue with the APIM chip in my 2017, which caused the interior screen to stay on even when the car was off. It wasn’t obvious because of the interior light timer, but the accessories were still on.

@Eli
Wow, that sounds really frustrating! Yes, we actually have a jump pack too, the kind you can use without needing another car. It’s been really useful!

There’s no auxiliary battery in regular gas Explorers. If your car’s been running fine until now, it’s probably time for a new battery. If the start/stop feature hasn’t been working, that could be a sign your battery’s weak. A 2021 Explorer should probably have its battery replaced by now. I replaced mine in my 2020 after a year.

@Denali
Thanks for the info! I’ve been putting it off, hoping it’s not a bigger issue, but looks like a new battery might be the solution!

@Denali
It’s not too bad, but you will need to remove some plastic covers to access the battery. Just make sure the positive leads are attached properly when you’re done. I’d recommend getting a battery from Costco or Sam’s Club, as they offer a 3-year warranty without any hassle. Also, be sure all the plastic covers are put back in place, especially the ones near the windshield.

@Denali
I’m definitely not doing the replacement myself! I meant that we can afford it, though. Thanks for all the tips!

I had the same issue with my 2020 Explorer. After about a year, it wouldn’t start in the morning. Even FordPass kept sending me low battery notifications. The dealer kept saying the battery was fine, but I insisted they replace it. Ever since, it’s been running perfectly. Looks like I’ll need another one soon though!

A battery test can miss some issues, especially when it comes to self-discharge problems that happen slowly over time.

I have a 2021 XLT and just replaced the battery at the dealer after 52k miles. Might be the same issue for you.

Ira said:
I have a 2021 XLT and just replaced the battery at the dealer after 52k miles. Might be the same issue for you.

Oh wow, I’ve only got 38k, but we live in Florida where the heat can definitely shorten battery life. That might be the cause!

You could try testing the battery from a friend or family member’s car. I’m not sure how the tests work, but my 2018 Explorer had a similar issue. The dealer said the battery was fine, but I replaced it myself and everything worked perfectly after that.

Don’t trust AutoZone’s battery tester. My car did the same thing. I trickle charged the battery and had AAA come out. Turns out, it had a bad cell. I brought the AAA printout to AutoZone, and they replaced the battery without any issues.