Auto Start/Stop Not Working

[TomZ]

I have a 2017 Fusion SE with the 1.5 liter engine purchased new as a leftover in March of 2018. The start/stop feature no longer seems to be working and the indicator light is still showing on. Even during normal weather with a minimum of accessories on, the engine won't turn off at a traffic light or a vehicle stop anymore.  The car has the original battery which now has 5 years of use on it plus the time it sat on a dealers lot unsold.

 

Looking around on the internet, it was suggested the battery might not have the capacity anymore for this to work. Is there a way to find out or should I just replace the battery because

of the age?

[andyross]

Just replace the battery. 5 years is an extraordinary lifetime for car batteries these days. I'm not sure if start-stop vehicles use a different deep-cycle battery.

[alcohenusa]

6 hours ago, andyross said:

Just replace the battery. 5 years is an extraordinary lifetime for car batteries these days. I'm not sure if start-stop vehicles use a different deep-cycle battery.

 

8 hours ago, TomZ said:

I have a 2017 Fusion SE with the 1.5 liter engine purchased new as a leftover in March of 2018. The start/stop feature no longer seems to be working and the indicator light is still showing on. Even during normal weather with a minimum of accessories on, the engine won't turn off at a traffic light or a vehicle stop anymore.  The car has the original battery which now has 5 years of use on it plus the time it sat on a dealers lot unsold.

 

Looking around on the internet, it was suggested the battery might not have the capacity anymore for this to work. Is there a way to find out or should I just replace the battery because

of the age?

Most Auto Stop/Start vehicles will use an AGM battery.  Go with the one that matches what the owner’s manual recommends.

[bbf2530]

10 hours ago, TomZ said:

I have a 2017 Fusion SE with the 1.5 liter engine purchased new as a leftover in March of 2018. The start/stop feature no longer seems to be working and the indicator light is still showing on. Even during normal weather with a minimum of accessories on, the engine won't turn off at a traffic light or a vehicle stop anymore.  The car has the original battery which now has 5 years of use on it plus the time it sat on a dealers lot unsold.

 

Looking around on the internet, it was suggested the battery might not have the capacity anymore for this to work. Is there a way to find out or should I just replace the battery because

of the age?

 

Hi TomZ. What andyross and alcohenusa stated. The first step would be to replace the battery. As you all have stated, the battery is ~7 years old, and may have sat for nearly a year before you purchased your 2017 model year Fusion in March of 2018.

 

It is likely a new battery will fix the issue. If not, then a deeper diagnosis may be necessary. But a new battery will probably do the trick.

 

Keep us updated and good luck.

[TomZ]

Finally got around to replacing the battery and now the auto start/stop is working perfectly. Thanks everyone for your help!

[NCEcoBoost]

I have the same vehicle as the topic starter but never use the stop/start feature because I HATE it.  That being said, I replaced my battery at the 3 1/2 year mark and plan to do so again in '24.  Because of the start/stop feature, I'm only going with a dealer battery replacement.

Ford recently offered to extend my extended warranty to 2026 for $30/month, which is great because of this funky new car market.  I'd planned on selling it in Fall '24, when the engine warranty ran out due to the scary coolant mixing issue.