Start/Stop Problem

[Jammalynn]

I just bought my first Wrangler in July. 2018 JL Sahara. The Start/Stop function wasn’t working but I read that if the A/C was on it didn’t work so I really worried about it. A few days ago it was finally cool enough to not run the A/C and turn Start/Stop Stop still wasn’t working. I scrolled through the menu and saw the message Battery Charging. Even after driving it Start/Stop wasn’t working. I thought I had a 3 month 3,000 mile warranty so I took it in. I was told the sensor was bad and that the sensor and both batteries need to be replaced. $868.88! AND it was not covered by the warranty. (That was only for the power train they said) UGH!

Can I have the Start/Stop disabled completely and just replace the mail battery? Any info on this would be helpful.

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[cripton805]

They sold you a Jeep with bad batteries... Not cool.

 

[Rustynail11]

if it isn't working then no need to disable it but yes you can get a Tazer Mini or a similar programmer to disable that function

 

[Jammalynn]

if it isn't working then no need to disable it but yes you can get a Tazer Mini or a similar programmer to disable that function

They told me the sensor and both batteries have to be replaced. My question is, Do I have to replace the sensor and auxiliary battery if I don’t want to use Start/Stop?

 

[Jammalynn]

They sold you a Jeep with bad batteries... Not cool.

I think so too. Manager is out until Monday. Maybe they will realize not fixing it is bad for their business.

 

[Heimkehr]

I just bought my first Wrangler in July. 2018 JL Sahara. I was told the sensor was bad and that the sensor and both batteries need to be replaced. $868.88! AND it was not covered by the warranty.

If the batteries are original to your 2018 Jeep, it's entirely possible that they're reaching the end of their practical service life. The dodginess of the Start/Stop function may simply be a manifestation of their age. Aging batteries can cause any number of seemingly unrelated electric issues/problems (voice of experience here.) Do consider replacing both of them as a prophylactic measure. Possibly the "sensor" that they claim is a problem...isn't. New batteries should make plain whether or not it's faulty.

Yes, that battery replacement wasn't done prior the sale, by a dealership who should arguably know better, is a mild annoyance.

 

[Htfan]

They told me the sensor and both batteries have to be replaced. My question is, Do I have to replace the sensor and auxiliary battery if I don’t want to use Start/Stop?

Don't why they told you to replace the sensor. How do they know it failed, if it's doing its job sensing a bad battery and disabling Start/stop.

1) Replace the bad batteries - dealer should take care of this if they just sold it to you in July.

2) disable start/stop (ESS) - with one of the products available on the market for purchase

 

[Jammalynn]

Don't why they told you to replace the sensor. How do they know it failed, if it's doing its job sensing a bad battery and disabling Start/stop.

1) Replace the bad batteries - dealer should take care of this if they just sold it to you in July.

2) disable start/stop (ESS) - with one of the products available on the market for purchase

They told me that the sensor overcharged both batteries. I plan to get something to disable this feature. Any suggestions?

 

[Derek]

I had this happen to me in Nov. I replaced the 12 volt battery and it shut off at the first stop sign. No other signs that the battery wasn’t healthy, started fine, drove fine, winched fine…

Jeep is a 2018
Engine is 2.0 turbo and electric generator (12 volt and 48 volt batteries)

 

[Bob Burd]

They gave you a load of crap. Over charging is highly, highly unlikely.

 

[Fudster]

Can I have the Start/Stop disabled completely and just replace the mail battery? Any info on this would be helpful.

Your query I suspect occupies more discussion on the forum than any other single topic.

You ask two distinct questions. Restated, you could a) prevent Start Stop from engaging, or b) run with one or two batteries, or c) both. Not that its recommended or what you want but you could even d) run Start Stop with one battery.

On the one hand I don't want this answer to be as long as "War and Peace." On the other hand I don't know what I can assume you already know.

Still more, the earlier 2018 3.6L (like you may have) JLs won't crank without either an auxiliary battery with ample power (which could be too little power to engage ESS,) or its cables rerouted to the main battery, or TSB 18-092-19 installed from the dealer. At cold crank the Aux battery is normally isolated for a second from the main battery, which it is connected to it in parallel with the factory wiring at all times but this instant and during ESS events.

If you have one of these older 2018s and bought your vehicle from the dealer, I would hope that they applied this TSB before the sold you the vehicle, but it may not be required like bringing all recalls up to date before putting the vehicle in your hands.

That's a lot to digest for a newbie, but nonetheless the facts.

Since the introduction of your model year, forum members have come up with 2 primary ways to get around this battery isolation and keep both batteries in parallel at all times. The initial method involved jumpering two connections in the PDC (Power Distribution Center), and the current easier method involves pulling a fuse in the PDC https://www.jlwranglerforums.com/forum/threads/jumperless-aux-battery-bypass.95945/

The PDC is that black box under the hood, on top, closest to the front passenger's seat. It's your vehicle's fuse box with logic encoded within it.

Using either method I describe above prevents the auxiliary battery from being isolated, channeling all requests for power from it to both batteries. This also means that once you've done either method, if you want, you (the dealer won't do this for you) can take the Auxiliary battery completely out of the electrical system of the vehicle if you want, the easiest way to do so being to disconnect the black cable from this battery that attaches to the negative pole of the main battery.

At the negative pole of the main battery expect to see two black cables. The other end of one of those cables leads to the body ground on the front passenger's quarter panel. Leave that alone. It's the other cable you disconnect, wrapping its end it electric tape.

Again--don't do this before the jumper or fuse technique above is effected if you have an old 2018 3.6 without TSB 18-092-19. (I can only imagine how my words must sound to the inexperienced!!!)

Now for the second part of your question, turning off ESS....

Your going to want to do this if you run just one battery even if you loved rather than hated ESS.

This is because engaging ESS with the one main battery is robbing that battery of cranking power after the ESS event. Normally, appliances run solely off the Auxiliary battery during an ESS event to preserve this cranking power. Sure, other vehicles run ESS with one battery but the dual battery JLs aren't designed for this.

There must be over 1/2 dozen ways to disable ESS, and I'll put the techniques in 3 categories.

The first is pushing the ESS off button after every crank. The second are DIY techniques for insuring ESS doesn't engage, like disconnecting (or better, turning sideways https://www.jlwranglerforums.com/forum/threads/free-ess-disable-via-hood-pin.15350/) the hood open sensor closest to the driver's seat, or with TSB 18-092-19 installed or a later model 2018 or later, pulling that black cable, and attempting to crank the vehicle twice. The second attempt will move all power to the main battery, and like disconnecting the hood sensor discussed throw an error light in the display (EVIC) turning ESS off.

Some people don't like the idiot lights. And some of these DIYs come with side effects. For example, I think disconnecting (not turning sideways) the hood sensor disables remote engine start functionality.

The 3rd category of ways to turn off ESS is through the purchase of tech to do so. From the Smart Start/Stop module, to the Z Automotive Tazer JL, and other toys, that allow you to program ESS to always be off. The former is cheaper and just does an ESS shutoff; the latter more expensive with many additional features.

That's already too much for 1 post.

 

[U EEDIOT]

Your query I suspect occupies more discussion on the forum than any other single topic.

You ask two distinct questions. Restated you could prevent Start Stop from engaging, or run with one or two batteries, or both. Not that its recommended or what you want but you could even run Start Stop with one battery.

On the one hand I don't want this answer to be as long as "War and Peace." On the other hand I don't know what I can assume you already know.

Still more, the earlier 2018 3.6L (like you may have) JLs won't crank without either an auxiliary battery with ample power (which could be too little power to engage ESS,) or its cables rerouted to the main battery, or TSB 18-092-19 installed from the dealer. At cold crank the Aux battery is normally isolated for a second from the main battery, which it is connected to it in parallel with the factory wiring at all times but this instant and during ESS events.

If you have one of these older 2018s and bought your vehicle from the dealer, I would hope that they applied this TSB before the sold you the vehicle, but it may not be required like bringing all recalls up to date before putting the vehicle in your hands.

That's a lot to digest for a newbie, but nonetheless the facts.

Since the introduction of your model year, forum members have come up with 2 primary ways to get around this battery isolation and keep both batteries in parallel at all times. The initial method involved jumpering two connections in the PDC (Power Distribution Center), and the current easier method involves pulling a fuse in the PDC https://www.jlwranglerforums.com/forum/threads/jumperless-aux-battery-bypass.95945/

The PDC is that black box under the hood, on top, closest to the front passenger's seat. It's your vehicle's fuse box with logic encoded within it.

Using either method I describe above prevents the auxiliary battery from being isolated, channeling all requests for power from it to both batteries. This also means that once you've done either method, if you want, you (the dealer won't do this for you) can take the Auxiliary battery completely out of the electrical system of the vehicle if you want, the easiest way to do so being to disconnect the black cable from this battery that attaches to the negative pole of the main battery.

At the negative pole of the main battery expect to see two black cables. The other end of one of those cables leads to the body ground on the front passenger's quarter panel. Leave that alone. It's the other cable you disconnect, wrapping its end it electric tape.

Again--don't do this before the jumper or fuse technique above is effected if you have an old 2018 3.6 without TSB 18-092-19. (I can only imagine how my words must sound to the inexperienced!!!)

Now for the second part of your question, turning off ESS....

Your going to want to do this if you run just one battery even if you loved rather than hated ESS.

This is because engaging ESS with the one main battery is robbing that battery of cranking power after the ESS event. Normally, appliances run solely off the Auxiliary battery during an ESS event to preserve this cranking power. Sure, other vehicles run ESS with one battery but the dual battery JLs aren't designed for this.

There must be over 1/2 dozen ways to disable ESS, and I'll put the techniques in 3 categories.

The first is pushing the ESS off button after every crank. The second are DIY techniques for insuring ESS doesn't engage, like disconnecting (or better, turning sideways https://www.jlwranglerforums.com/forum/threads/free-ess-disable-via-hood-pin.15350/) the hood open sensor closest to the driver's seat, or with TSB 18-092-19 installed or a latter model 2018 or later, pulling that black cable, and attempting to crank the vehicle twice. The second attempt will move all power to the main battery, and like disconnecting the hood sensor discussed throw an error light in the display (EVIC) turning ESS off.

Some people don't like the idiot lights. And some of these DIYs come with side effects. For example, I think disconnecting (not turning sideways) the hood sensor disables remote engine start functionality.

The 3rd category of ways to turn off ESS is through the purchase of tech to do so. From the Smart Start/Stop module, to the Z Automotive Tazer JL, and other toys, that allow you to program ESS to always be off. The former is cheaper and just does an ESS shutoff; the latter more expensive with many additional features.

That's already too much for 1 post.

 

[58Willys]

Replace both batteries. If you don’t they will both fail again soon.

 

[Fudster]

I hear you.

I probably even earned that, much as I tried to explain in simple terms....but simple means explaining, and explaining requires words.

If you have a question know that you can ask it "like a 3 year old," and I won't judge you, answering what I know in simple terms.

The OP asked a question with no easy answer. Plenty of people offered ideas in 2 sentences that likely and blindly address the OPs situation in part w/o explanation.

Given everyone prior said "do this," I thought I'd point out why.

 

[Reinen]

The answer to the OPs question is simple. Replace both the Main and Aux batteries. That's it.

1. ESS is a canary in the coal mine for battery issues. It's nearly always the first thing to go when batteries start going bad but it isn't essential. Don't ignore it. It's just a matter of time before some other essential electrical component starts failing strangely and you could very well be stranded.
2. Ignore what the dealer said about the sensor. It's very likely they sold you a Jeep with practically dead batteries and are finding a scapegoat to blame, adding a sensor to your bill to do it. That should tell you all you need to know about them. If it's a 2018 with original batteries, they've already lasted longer than average.
3. Always replace both Main and Aux batteries at the same time. The batteries are always linked, except during starts. If you do not replace both, the one that wasn't replaced will severely shorten the lifespan of the new battery.

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