Auto Stop Start stoped working?
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Junior Member
Joined: Jan 2025
Posts: 2
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Auto Stop Start Stopped Working?
I know most people hate this feature but I prefer it on.
The feature recently stopped working does anyone have a suggestion for troubleshooting?
I’ve already tried using the button to turn it off and then back on again.
If I were stopped at a light and it hadn’t activated I could usually get it to activate by stepping harder on the brake.
The engine used to turn off if the feature was activated and I removed the seat belt but it no longer does that either.
Thanks.
The feature recently stopped working does anyone have a suggestion for troubleshooting?
I’ve already tried using the button to turn it off and then back on again.
If I were stopped at a light and it hadn’t activated I could usually get it to activate by stepping harder on the brake.
The engine used to turn off if the feature was activated and I removed the seat belt but it no longer does that either.
Thanks.
Veteran Member
Joined: May 2013
Posts: 7,037
Likes: 2,700
From: Metrowest Boston
What year is your car? Early cars (like mine) had a 2nd battery. I removed my 2nd battery when it failed.
Also, as mentioned, a low or failing primary battery will disable start/stop. I had this happen in my XE.
Also, as mentioned, a low or failing primary battery will disable start/stop. I had this happen in my XE.
Senior Member
Joined: Feb 2024
Posts: 116
Likes: 40
From: San Francisco Bay Area
I have a 2015 R, and mine was also not working. Mine has a second smaller auxiliary battery in the trunk of the car, on the opposite side of the primary battery.
I replaced the auxiliary battery, and the start/stop started working again. Useful when stuck in stop and go traffic.
I replaced the auxiliary battery, and the start/stop started working again. Useful when stuck in stop and go traffic.
Senior Member
Joined: Dec 2024
Posts: 284
Likes: 200
From: UK
Consider it a blessing. Auto stop is a silent engine killer. It puts so much stress on the engine, oil pump and the constant oil pressure drop could cause bore scoring among other issues.
Switching it off is part of my get ready to take off process 😊
Switching it off is part of my get ready to take off process 😊
Last edited by WSHudds; Feb 4, 2025 at 08:34 AM.
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Veteran Member
Joined: Oct 2020
Posts: 1,461
Likes: 615
From: Wisconsin
+1 on turning off S/S
I understand the S/S is to improve gas mileage rating, but I do not see anything good coming out of repeated offs/ons to starters, oil levels, etc. already described above.
With my 6 speed, it's Power On, let the car settle down to idle, Dynamic On, Active Exhaust on, S/S OFF. Go have fun!
With my 6 speed, it's Power On, let the car settle down to idle, Dynamic On, Active Exhaust on, S/S OFF. Go have fun!
Senior Member
Joined: Feb 2024
Posts: 116
Likes: 40
From: San Francisco Bay Area
When I turn on Dynamic, s/s automatically goes off.
I have model year 2015. Is it different than other model years?
(It’s raining now where I am, so I have rain mode on. Same thing: s/s automatically disabled with rain mode on.)
I have model year 2015. Is it different than other model years?
(It’s raining now where I am, so I have rain mode on. Same thing: s/s automatically disabled with rain mode on.)
Veteran Member
Joined: Aug 2018
Posts: 2,266
Likes: 933
From: Exit 30 in NorthWest NJ
Having the engine OFF in stop-n-go situations reduces pollution too, a factor in European standards..
Supposedly there are designed-in mitigations to the automatic transmission hydraulics, and engine oil pump.
In theory, these things are important, but in practice...probably not so much.
I do not see anything good coming out of repeated offs/ons to starters, oil levels, etc. already described above
In theory, these things are important, but in practice...probably not so much.
Veteran Member
Joined: Jun 2018
Posts: 1,618
Likes: 755
From: Granite Bay, CA
Yes. The first couple of years had a secondary battery that was dedicated to the Stop/Start.
Last edited by eeeeek; Feb 4, 2025 at 02:07 PM.
Veteran Member
Joined: Jun 2018
Posts: 1,618
Likes: 755
From: Granite Bay, CA
I know most people hate this feature but I prefer it on.
The feature recently stopped working does anyone have a suggestion for troubleshooting?
I’ve already tried using the button to turn it off and then back on again.
If I were stopped at a light and it hadn’t activated I could usually get it to activate by stepping harder on the brake.
The engine used to turn off if the feature was activated and I removed the seat belt but it no longer does that either.
Thanks.
The feature recently stopped working does anyone have a suggestion for troubleshooting?
I’ve already tried using the button to turn it off and then back on again.
If I were stopped at a light and it hadn’t activated I could usually get it to activate by stepping harder on the brake.
The engine used to turn off if the feature was activated and I removed the seat belt but it no longer does that either.
Thanks.
Veteran Member
Joined: May 2015
Posts: 3,966
Likes: 1,315
From: Northern California
If the battery is not sufficiently charged, start/stop will be disabled. I think the fears about it are overblown, I usually have mine disabled. I don't want it to stop the car if I know it will only be for 5-10 seconds. I will enable it when I feel it will be helpful, e.g. long stoplights, but I avoid routes like that when possible.
I did notice it stopped working a few years ago. I had the dealer check it because I was under warranty and they replaced the battery. That fixed it.
I did notice it stopped working a few years ago. I had the dealer check it because I was under warranty and they replaced the battery. That fixed it.
Veteran Member
Joined: May 2013
Posts: 7,037
Likes: 2,700
From: Metrowest Boston
For those interested, this document has detailed start/stop info…
https://www.dropbox.com/scl/fi/fturj...=ns81kk9u&dl=0
https://www.dropbox.com/scl/fi/fturj...=ns81kk9u&dl=0
Before the engine is stopped the following parameters must be detected:
The vehicle must be stopped from a speed greater than 4 km/h (2.5 mph)
Sufficient brake pressure must be applied to the brake pedal to ensure the vehicle is stationary
OR
The vehicle must be stationary and 'P' or 'N' selected on the TCS.
Before the engine is restarted, the following parameters must be detected:
The accelerator pedal is pressed (ECM detects a signal from the APP (Accelerator Pedal Position) sensor)
The vehicle speed exceeds approximately 1 km/h (0.5 mph)
Climate control system demand increases (signal from the ATCM (Automatic Temperature Control Module))
Brake vacuum has been reduced from repeated use of brake pedal with engine not running (detected by ECM
from the brake vacuum sensor)
Battery charge becomes low
Auto stop/start is deactivated using the Auto stop/start switch in the floor console
A steering wheel paddle switch is operated to select a gear
'D' (Drive) or 'S' (Sport) selected on the TCS and the brake pedal is released
'R' (Reverse) is selected on the TCS.
The following conditions will prevent an Auto stop:
The external ambient temperature is less than 0°C (32°F) (detected by the ECM via the AAT (Ambient Air
Temperature) sensor)
The external ambient temperature is more than 40°C (104°F) (detected by the ECM via the AAT sensor)
The engine has not reached its optimum operating temperature (detected by the ECM via the ECT (Engine
Coolant Temperature) sensor)
The driver door is opened (detected by the CJB from the door ajar switch)
The driver safety belt is not fastened (detected by the RCM (Restraints Control Module) from the driver seatbelt
buckle switch)
The climate control system requires the engine to be running, for example; windshield demist selected
The battery charge is low (signal from the GWM)
The hood is open (detected by the CJB from the hood ajar switch)
Auto stop/start is deactivated using the Auto stop/start switch in the floor console
A steering wheel paddle switch has been used to select a gear.
The vehicle must be stopped from a speed greater than 4 km/h (2.5 mph)
Sufficient brake pressure must be applied to the brake pedal to ensure the vehicle is stationary
OR
The vehicle must be stationary and 'P' or 'N' selected on the TCS.
Before the engine is restarted, the following parameters must be detected:
The accelerator pedal is pressed (ECM detects a signal from the APP (Accelerator Pedal Position) sensor)
The vehicle speed exceeds approximately 1 km/h (0.5 mph)
Climate control system demand increases (signal from the ATCM (Automatic Temperature Control Module))
Brake vacuum has been reduced from repeated use of brake pedal with engine not running (detected by ECM
from the brake vacuum sensor)
Battery charge becomes low
Auto stop/start is deactivated using the Auto stop/start switch in the floor console
A steering wheel paddle switch is operated to select a gear
'D' (Drive) or 'S' (Sport) selected on the TCS and the brake pedal is released
'R' (Reverse) is selected on the TCS.
The following conditions will prevent an Auto stop:
The external ambient temperature is less than 0°C (32°F) (detected by the ECM via the AAT (Ambient Air
Temperature) sensor)
The external ambient temperature is more than 40°C (104°F) (detected by the ECM via the AAT sensor)
The engine has not reached its optimum operating temperature (detected by the ECM via the ECT (Engine
Coolant Temperature) sensor)
The driver door is opened (detected by the CJB from the door ajar switch)
The driver safety belt is not fastened (detected by the RCM (Restraints Control Module) from the driver seatbelt
buckle switch)
The climate control system requires the engine to be running, for example; windshield demist selected
The battery charge is low (signal from the GWM)
The hood is open (detected by the CJB from the hood ajar switch)
Auto stop/start is deactivated using the Auto stop/start switch in the floor console
A steering wheel paddle switch has been used to select a gear.
Veteran Member
Joined: Jan 2023
Posts: 1,786
Likes: 751
From: Ontario, Canada
If only this feature would break, I’d be a happy man. Then I wouldn’t have to remember to disable it or look into disabling it somehow…On my list of things to do at some point. I cannot stand that feature.
Senior Member
Joined: Aug 2020
Posts: 873
Likes: 621
From: Western MA
If you have a convertible, smartTOP can take care of this for you.
Veteran Member
Joined: Jan 2023
Posts: 1,786
Likes: 751
From: Ontario, Canada
I have a coupe. Does that mean there is no clean solution like pulling a fuse or something? I kind of assumed to this point that it might be something simple like that, but I’m getting the impression that this is not the case based in your comment.
Veteran Member
Joined: May 2013
Posts: 7,037
Likes: 2,700
From: Metrowest Boston
There’s a connector in the trunk you can unplug, it’s been posted here quite a few times. I’ll see if I can find it…
Edit: here it is…
https://www.jaguarforums.com/forum/f...attery-146010/
Edit: here it is…
https://www.jaguarforums.com/forum/f...attery-146010/
Last edited by DJS; Feb 5, 2025 at 10:55 AM.
Veteran Member
Joined: Jan 2023
Posts: 1,786
Likes: 751
From: Ontario, Canada
There’s a connector in the trunk you can unplug, it’s been posted here quite a few times. I’ll see if I can find it…
Edit: here it is…
https://www.jaguarforums.com/forum/f...attery-146010/
Edit: here it is…
https://www.jaguarforums.com/forum/f...attery-146010/
Junior Member
Joined: Feb 2020
Posts: 2
Likes: 0
From: Fontana
[QUOTE=GAT1174;2821555]I know most people hate this feature but I prefer it on.
The feature recently stopped working does anyone have a suggestion for troubleshooting?
I’ve already tried using the button to turn it off and then back on again.
If I were stopped at a light and it hadn’t activated I could usually get it to activate by stepping harder on the brake.
The engine used to turn off if the feature was activated and I removed the seat belt but it no longer does that either.
Thanks.[/QUOTE
most likely it's a separate battery
That it is used to power that option
The feature recently stopped working does anyone have a suggestion for troubleshooting?
I’ve already tried using the button to turn it off and then back on again.
If I were stopped at a light and it hadn’t activated I could usually get it to activate by stepping harder on the brake.
The engine used to turn off if the feature was activated and I removed the seat belt but it no longer does that either.
Thanks.[/QUOTE
most likely it's a separate battery
That it is used to power that option