Boost_Crazy
Boost_Crazy Dork
2/27/24 3:23 p.m.

My 2019 Expedition is at the dealer for warranty work. They have had it a week or so to fix some oil leaks. Now they are supposed to check out a hard shifting issue with the transmission (replaced under warranty last year.) They said they can't diagnose the transmission issue until they address "a bunch of low voltage codes." They want to replace the battery at $300+. It's an AGM, so I know they are expensive, but it has shown zero signs of a battery issue. There were no codes, stored or pending, the week before I took It in. Coincidentally, I used the Expedition to demonstrate how to use my code reader that I was lending out. It's a mid grade reader, but it should have shown any codes, right? And I can't find any info on "codes", just one low voltage code, which in my brief research is usually not the battery. 

I don't want to spring for a new battery if it's not needed. No symptoms of a bad battery before. It has around 50,000 miles on it, and has been in use for just over 4 years (Sold originally at the end of 2019.) An AGM should last longer than that?

I'll find out what codes they are talking about. I wouldn't be surprised if a battery cable wasn't tightened after recent work. They did fix an oil leak at the timing cover, I'm guessing the alternator needed to be removed? It's against my religion to pay a dealership to change a battery, but I'm kind of stuck- it took months to schedule this appointment and secure a loaner car. I don't want the Expedition back until it's done. What do you guys think my next step should be? 

RacetruckRon
RacetruckRon GRM+ Memberand SuperDork
2/27/24 4:19 p.m.

Download FORSCAN and get an appropriate cable so you can read BMC level codes and diagnose accordingly.

sevenracer
sevenracer HalfDork
2/27/24 10:18 p.m.

Don't know about throwing codes, but my 2017 f150 started giving me warnings on the screen occasionally plus not ever allowing start stop operation, and shutting down earlier than the 30 minute timeout for engine off, accessories on. 

No other symptoms of a weak battery. Drove it like that for over a year, but replaced it before a big trip. I measured voltage at like 12.2 volts. 

All that was to say, your battery could actually be weak per the vehicle's parameters. I've heard anecdotally of 3-4 years lifespan for the agm in f150's. I paid around 250 for a Ford agm from advance auto. If it's original, I'd likely let them change it to keep them focused on the bigger transmission issue.

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Boost_Crazy
Boost_Crazy Dork
2/27/24 10:26 p.m.

In reply to RacetruckRon :

That would be a good idea, but it's at the dealer now. I either pick it up as is, address the battery myself, and try to make another appointment and get a loaner car to finish diagnosing the tranny. This took over a month the last two times. Or I pay them for a battery it may not need and they take care of the tranny. 
 

The car showed no signs of battery issue before it went to the dealer. No codes, auto stop start still worked (I think this is automatically disabled if battery voltage is low.) They said it starts, and they "drove it around a bit to try to charge the battery." I thought a large Ford dealer would have a better battery charging option than that. They texted me the codes. Hard to read their blurry pics of the computer screen-

Should any of these codes been apparent, either with a check engine light or with my scan tool? I have a hard time believing all of these codes were there before we dropped it off. 

Boost_Crazy
Boost_Crazy Dork
2/27/24 10:45 p.m.

In reply to sevenracer :

Don't know about throwing codes, but my 2017 f150 started giving me warnings on the screen occasionally plus not ever allowing start stop operation, and shutting down earlier than the 30 minute timeout for engine off, accessories on. 

No other symptoms of a weak battery. Drove it like that for over a year, but replaced it before a big trip. I measured voltage at like 12.2 volts. 

All that was to say, your battery could actually be weak per the vehicle's parameters. I've heard anecdotally of 3-4 years lifespan for the agm in f150's. I paid around 250 for a Ford agm from advance auto. If it's original, I'd likely let them change it to keep them focused on the bigger transmission issue.
 

Thanks, that helps. I expected more than 4 years, but if that's normal, it could be due. It would be strange to me that a bad battery would give no other signs.

Datsun240ZGuy
Datsun240ZGuy MegaDork
2/27/24 10:51 p.m.

Four years is what I get on my batteries.  Pay them the $300 and have them fix the warranty issues.

Boost_Crazy
Boost_Crazy Dork
3/6/24 11:47 p.m.

Well I paid the dealer to change the battery. That hurt. But at least they were able to finish the transmission diagnosis. They believe the battery solved the issue. I'm not optimistic, but fingers crossed. I am disappointed that after buying a very expensive new battery that is not known for a long life- the dealer neglected to reinstall the  battery heat shield! No wonder I have such little faith and trust in the average person to do a job correctly. And this wasn't an average shop, this was the Ford dealer! 

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