ESS not working...

[R3TRO]

I guess I shouldn't complain, but just want to make sure nothing's up.

About 18mo ago dealer changed out both main and aux batteries. A few months ago the ESS light came up saying auto start/stop disabled. So I decided to disconnect the aux neg cable and pull fuse 42. Still I get ESS disabled. I was under the impression that would still work even without an aux battery assuming the main battery state of charge is good.

So my question is, how does below look? Everything looks good to me except the starting voltage. I'll eventually replace with h7, but until then just want peace of mind. Thanks for any input!

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[THAW]

Starting voltage dropping to 8.9 V indicates the battery should be replaced.

 

[WranglerMan]

Main volts is low but can be corrected with a good slow trickle charge, resistance is good, CCA’s is low but temperature can affect that but once starting voltage drops below 9-9.5 indicates a replacement.

I would put it on a slow trickle charge overnight and do another test if numbers don't come up as suggested replace the batteries, a bad aux batt is known to pull the main down.

 

[R3TRO]

Main volts is low but can be corrected with a good slow trickle charge, resistance is good, CCA’s is low but temperature can affect that but once starting voltage drops below 9-9.5 indicates a replacement.

I would put it on a slow trickle charge overnight and do another test if numbers don't come up as suggested replace the batteries, a bad aux batt is known to pull the main down.

Thanks for the feedback! I do have a trickle charger. I'll give that a try.

 

[AndySpill]

I guess I shouldn't complain, but just want to make sure nothing's up.

About 18mo ago dealer changed out both main and aux batteries. A few months ago the ESS light came up saying auto start/stop disabled. So I decided to disconnect the aux neg cable and pull fuse 42. Still I get ESS disabled. I was under the impression that would still work even without an aux battery assuming the main battery state of charge is good.

So my question is, how does below look? Everything looks good to me except the starting voltage. I'll eventually replace with h7, but until then just want peace of mind. Thanks for any input!

I trust that you're aware of this Steven, but if not, or if others can glean wisdom from the following:

Switching to a one battery solution often gets rid of ESS not ready warnings--as much as running the ESS system on one battery in a factory dual AGM battery JL is probably not advised--for perhaps more this reason than any, because...

the pre-cold crank test of the factory ESS/Aux battery performed by the vehicle is rerouted to the main battery as a result of the cable and fuse 42 pull.

Pulling Fuse 42 prevents the Power Control Relay (PCR) from ever being energized, which when it is separates the two factory batteries in JLs equipped as such, and as normally occurs at two points: an instant prior to cold crank as mentioned, and during ESS events.

ESS not ready in such cable/fuse pulls lends strong support for the need to load test the main battery and replace it if needed. Sadly, it sounds like you had over a year for that replaced Aux battery to possible effect harm to the main battery replaced concurrently before you migrated to the one battery situation.

 

[andy29847]

Do it now!

 

[andy29847]

R3TRO wrote: "About 18mo ago dealer changed out both main and aux batteries. A few months ago the ESS light came up saying auto start/stop disabled. So I decided to disconnect the aux neg cable and pull fuse 42. Still I get ESS disabled. I was under the impression that would still work even without an aux battery assuming the main battery state of charge is good.

So my question is, how does below look? Everything looks good to me except the starting voltage. I'll eventually replace with h7, but until then just want peace of mind. Thanks for any input! "

-----------------------------------

First of all, make sure your dealer used an AGM battery when they did the battery change 18 months ago. The Jeep charging system is designed for AGM batteries. If your dealer put in a lead acid battery, he owes you new batteries.

Next, it doesn't matter to your ESS system if you have one battery or 2 batteries. The ESS system functions the same regardless. The ESS disabled message is indicative of something wrong (proof that the ESS guards are still in place even though you just have one battery).

About your battery....it failed the test. Replace it. I'd guess the low starting voltage is caused by problems inside the case, maybe a connection that is failing.

 

[R3TRO]

I trust that you're aware of this Steven, but if not, or if others can glean wisdom from the following:

Switching to a one battery solution often gets rid of ESS not ready warnings--as much as running the ESS system on one battery in a factory dual AGM battery JL is probably not advised--for perhaps more this reason than any, because...

the pre-cold crank test of the factory ESS/Aux battery performed by the vehicle is rerouted to the main battery as a result of the cable and fuse 42 pull.

Pulling Fuse 42 prevents the Power Control Relay (PCR) from ever being energized, which when it is separates the two factory batteries in JLs equipped as such, and as normally occurs at two points: an instant prior to cold crank as mentioned, and during ESS events.

ESS not ready in such cable/fuse pulls lends strong support for the need to load test the main battery and replace it if needed. Sadly, it sounds like you had over a year for that replaced Aux battery to possible effect harm to the main battery replaced concurrently before you migrated to the one battery situation.

R3TRO wrote: "About 18mo ago dealer changed out both main and aux batteries. A few months ago the ESS light came up saying auto start/stop disabled. So I decided to disconnect the aux neg cable and pull fuse 42. Still I get ESS disabled. I was under the impression that would still work even without an aux battery assuming the main battery state of charge is good.

So my question is, how does below look? Everything looks good to me except the starting voltage. I'll eventually replace with h7, but until then just want peace of mind. Thanks for any input! "

-----------------------------------

First of all, make sure your dealer used an AGM battery when they did the battery change 18 months ago. The Jeep charging system is designed for AGM batteries. If your dealer put in a lead acid battery, he owes you new batteries.

Next, it doesn't matter to your ESS system if you have one battery or 2 batteries. The ESS system functions the same regardless. The ESS disabled message is indicative of something wrong (proof that the ESS guards are still in place even though you just have one battery).

About your battery....it failed the test. Replace it. I'd guess the low starting voltage is caused by problems inside the case, maybe a connection that is failing.

Thanks for all the informative responses!

Yes I double checked, is H6 AGM type battery. And no I was not aware of 'exactly' how the ESS system works! Looks like it's time for an H7 upgrade. I always carry one of those portable jumpers, but I don't want to make a habit of relying on it.

Lots of friends/family/co-workers all have cars with auto start/start and I seem to be the only one ever having any problems with it?! Almost as if it's a Jeep thing...

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