Auto stop start (ESS) permanent disable / defeat by unplugging hood sensor

Rhinebeck01

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Has anyone tried removing the ESS battery? My jeep should arrive this month and I'm curious as to how the jeep behaves if I just remove this secondary battery. Thanks
@jeepinoutwest

Well, if you just remove the ESS battery, the JL will, among other things, not start, even though the main battery is attached and fully charged.
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jeepinoutwest

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Thanks exactly what I wanted to know. Thank you. Rhinebeck, can you explain to me why that works that way? I was under the impression that small second battery was only for the accessories when the Jeep was not running because ESS was triggered.
 

szobell

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But you can disconnect the wire on the main battery that goes to the ESS battery and it disables ESS. I have done this on my JL and my Chrokee. Aside from a little indicator on the dash, it is as though there is no ESS on the vehicles.
 

jeepinoutwest

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Cool, that's my plan or the 2nd hood pin switch. The dash light wont phase me.
 

GSGZZLR

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My ASS (lol) never worked straight from the lot. The warning light is on showing that the system is off. If I press the button, nothing happens. I wish I knew what is wrong so that the rest of you can copy it.
 

szobell

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My guess is the connector on the main battery is disconnected or the 2nd is bad. I have actually disconnected the battery cinnector on my KL and i have the error light and no ESS
 

cobra

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Well it's been really cold around here [20's] and my defroster hasn't been doing it's job so i had to plug the damper motor back in. Guess i'll have to deal with the cold air coming in occasionally until it warms up some.
 

WranglerMan

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I still need to unplug mine, I seem to never remember to do this until I have that blast of warm humid air
 

smithrd65

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Just push the DARN BUTTON.
It's like I don't want to flush the toilet why do I have to push a button to let my windows down. I have to turn on the stove.
But that darn Jeep Button makes me so tired how silly.
 

theplankeye

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It is not that it is hard to do, it is just forgotten easily. Then, you end up looking like a moron at the stoplight when your engine dies.
 

HoundDude

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bobUK

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Hi guys,

To get rid of stop/start I removed the negative rail sensor on my Petrol CGI 2012 Merc C-Class 6 months ago, (system is similar to yours I believe) with no issues or EML on dash.
If the EMU can`t read the data from the sensor it does not know the SOC of the battery and (1) will not engage the Stop/start function as car may not restart, (2) disables smart charge and puts the alternator into default charging mode (pre smart charge). You may notice a slight drop in MPG with these two not engaged. In default charge mode your battery will be charged at between 14.3 and 13.8 volts ensuring a fully charged battery when possible at all times unlike smart charge where the battery can be as low as 75-80% SOC waiting for any regeneration to occur.

With the sensor disconnected there is no need to register a new battery and as stop/start is not functioning there is also no need to use an expensive replacement AGM battery. The original AGM battery already in the car will obviously last considerably longer as there are less starts with stop/start disconnected (50,000 against 500,000 lifetime starts). With sensor disconnected there is also one less layer of electronics to go wrong.

Thats my take on it anyway.
 

Mrcake3014

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Today I unplugged hood open sensor #2 on right side (driver's side) of engine bay. According to the wiring and software schematics its only job is auto stop/start disable with hood open. It gave me the the auto start/stop warning dash symbol, but that start/stop feature was driving me crazy. I drove the JL 68 miles today with zero issues (remote start works as well as backup camera).

Yes I am too forgetful to press the ESS button to off at every startup. This will hold me over until I can figure out a better defeat technique for this very undesired feature.

Photo of the sensor:

jl-wrangler-hood-sensor-ESS-auto-start-stop-defeat.jpg
You know I'm a little concerned. I asked my dealership service if there was a hood sensor connected to the stop start system and they said no. I am getting a warning for stop start and it stalls out. Anyone else have this problem?
 

Jeepaddict76

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Has anyone experience issues from dealer while vehicle was in for service / warranty work?
 
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