Replaced main battery and got the ESS dash light

[Student12]

Initially thaough it was my key fob, but once I finally got in, I noticed a stiff brake pedal and "glued" my my keyfob to the push start button...still no juice. By the dash not lighting up, I figured it was the main battery.

Got it tested, results were that it practically had no juice, main battery has been replaced.

It's up & running currently, but I see the ESS light on the dash and now I'm wondering if the aux battery needs to be replaced or should I not worry about this. (FYI, I always have ESS disabled via tazer)

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[swtrailboss]

Yes a very good chance you will need to replace the aux battery if you haven’t already but the first question is did you fully charge your main battery when it was replaced?

 

[Mr._Bill]

Both batteries should be replaced at the same time, especially if it is that dead.

Both batteries are paralleled together all the time, except during the startup test and during ESS events.

 

[Student12]

Yes a very good chance you will need to replace the aux battery if you haven’t already but the first question is did you fully charge your main battery when it was replaced?

Nope, it was a free replacement. But it does have 760 CCA

 

[swtrailboss]

When you go to replace the auxiliary battery put both batteries on a charger to fully charge each separately before installing and remove the battery sensor from the negative post and unplug it for 5-10 minutes to reset it. Should be good to go.

 

[Lunentucker]

Bypass the AUX and keep rolling.
15 minute job.

 

[Student12]

Bypass the AUX and keep rolling.
15 minute job.

Fuse 42 ?

 

[Lost1wing]

Fuse 42 ?

And isolate the Aux ground cable from the main negative. Make sure it doesn't touch anything.

 

[ColoradoCantu]

You can ignore as long as you know the bypass steps but its just a matter of time, and it may drain your new battery. My main tested fine, I was getting the "Stop/Start Not Ready" for months before mine died while I was driving, I barely had enough momentum to get to a parking spot. When it goes, it goes. I was traveling on vacation and labor was covered, so I just had it replaced by the dealer, they recommended replacing the main but I didnt like their choices, I decided to wait til got back home and got a bigger size 94R Optima battery.

 

[Student12]

Update:

The dash light went away after a while of driving. I tried to keep an eye on the voltage menu. It had a range of 12.5v - 13v

I guessing even though the light went away, the aux is still draining the main battery.

 

[Lunentucker]

I got the part about it disabling ESS wrong on this video.
ESS will still work off one battery.
Everything else is accurate.

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