STOP / START NOT WORKING, WHY!?

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STOP/START is a feature on modern cars to reduce emissions by reducing the idle time on your engine when stationary. This works in theory but in reality, there are often issues causing this system to not work as intended.
there are certain criteria that needs to be met inorder for the system to work properly.
this differs from manufacturer to manufacturer so we always recommend checking out the owners manual for a comprehensive list, but we will go through the main reasons that people run into issues here.
1. AC, Your Air conditioning being active is considered too high a draw on the battery when the engine isnt running. the car recognises this and to prevent not having enough power to restart, it de activates the function all together.
2.Engine coolant temp. the biggest reason for wear on your engine is during a cold start up. this is because the oil hasn't been fed through the engine yet so the car intentionally waits until the coolant temperature is above a certain limit which ensures a good operating temp for the engine and that sufficient oil has gone through the internals of the engine. once this criteria is met, stop starts when warm have minimal wear effect.
3. Repeated stop starts. once a succesful stop and start has been carried out by the system, there is a minimum distance and/or speed that has to be met before another stop start can occur. this is to again ensure the engine has enough time to recirculate oil through the engine and prevent premature wear.
4.DPF clean. the diesel particulate filter collects soot from the engine and occasionally runs through a self clean procedure. while this procedure is being carried out the engine must remain running. if it is interrupted then the process will need to be repeated the next time the car is started up. the system knows this and de activates the stop start system to make sure it doesn't interrupt the procedure. too many failed dpf cleans can cause a blockage in the dpf.
5. Battery State of charge. the battery must be over 80% charged. if this threshold isnt met, then the stop start wont work. This is because the system weighs the risk on if there is enough charge to restart the engine similar to the AC issue.
if however the engine stops but you are waiting for a prolonged period of time, the battery may fall bellow the 80%. this would mean the auto start up kicks in before intended as a way to counter act the issue. this auto start up would kick in if any of the listed criteria isnt met.

Stop start complaints will be very common the more people start using their cars again after lockdown. we hope this video has given you something to think about if you run into these issues.

hope this helped, have a great day and STAY SAFE people!

[dmoore]

This is a great video. It’s a covert way of telling drivers how to permanently disable that crap.

[lozmorgan]

Great video. Stop start no point in having it more trouble than it worth

[kevinwinskill]

Very clear and precise information. I did not know any of this could affect the car stop/start operation. Thank you for explaining it to us more clearly 👍👍👍

[roberttaylor]

Thanks, The presenter appears to really know his subject . Video was very well presented, very informative & appeared to cover the issue well.

[NeoMorphUK]

Got a week old new car and was wondering why the stop/start wasn’t working… checked the battery and it’s at medium/low on the battery tester so that’s why the stop/start isn’t working.

Thanks for this info. Saved me having to hit the garage.

[ronniemacleod]

Excellent Information. I had iss8and I checked my main and auxiliary batteries.
Aux was fine but main was done.
Soon as I renewed stop/ start eco worked again.
My car is a 6 year old Mercedes E250 cdi.
Still a great motor and efficient too.

[keepgrindingup]

I can't believe people would actually complain if that system disabled itself permanently

[dennisbobrovsky]

Thanks for informative video! 👍 Our car stalled halfway, we didn't know what to do. So I watched this, turned all the heat, seat heating off, and it started, so we made it home.🙂

[intruder]

I'd deduced a lot of this a week into owning my first car with Stop-Start but also noticed that it tends to manifest as the car deciding it will or won't work at the start of a journey and then nothing I do on that journey will change it! I do noticed the failure tends to be on the outward journey after sitting for a a day or so so I guess it's almost always down to the battery charge (I was doing things like turning off the AC and even the heat/fan down).

I've decided to stop worrying about it now :)

[stephencross]

Thanks this has solved my issue with start stop not working. I didn't have time to put my car in the garage for diagnostic so this video has been a blessing thanks again 👍

[trekshogun]

Hi, thanks for the heads up, my Kia Sportage 1.7, has never worked since I bought it, probably air con on all the time!

[jessekozma]

To completely resolve this Turn that function off and never use it again.

One of the hardest things your car will ever have to do is start. It requires all of the battery power, repeated use of the starter motor and also provides you with a lovely lag when trying to go forward.

If you think about it on any given day for running errands you might start your car four to six times. When using the stop start function you're looking at 20 to 60 starts. The brushes in the starter motor will wear out prematurely, your battery is at constant strain.

Save yourself the headache and disable that function.

[maestrodicalcio]

Very useful thanks. Can someone tell me what health percentage does the battery need to reduce to before a new car battery is recommended? Because under %80 to me sounds like battery is still in relatively good health ?

[hazemtawfik]

Excellent and highly informative video. The picture is crisp clear and the narration is great and easy to follow

[carollangshaw]

This has put my mind at rest and i now know why the stop/start won't work. Many Thanks

[oojimmyflip]

We have a 2019 Citroen c5 AIRCROSS 1.5 diesel automatic and in 2 years of ownership and good maintenance it has only worked twice possibly because we always have the radio on and run the heater or air con system.

[kenyahlyle]

This was so helpful. My fiat 500 randomly shut off the stop/start and it worried me! especially since i had just serviced and MOT'd my car that month. Turns out i just needed some coolant and the aircon had shut it off as said. Thanks mate

[timwales]

Charged my battery for a few hours, even though I’ve been driving it, all ok now thanks for your helpful information

[geoffrichguitarist]

Good information, this obviously applies to all makes of car with s/s

[ninastanway]

I watched you video which was good advice. I've got a BMW 320 year 2012 and I've changed the original battery to a new one but unfortunately the stop start still doesn't work. Not sure what to do now.