Auto Start/Stop "Feature" in Vehicles

Beth Gallagher

Beth Gallagher

Well-known member
Anyone (in the USA) who has bought a new ICE vehicle in the past several years has been introduced to the Auto Start/Stop feature, usually against their will. Love it or hate it, it was another government mandated component that added cost to the bottom line and aggravation to the driver. It purportedly saves gasoline and reduces emissions, though I don't know if any of that is significant enough to justify the investment in research, retooling, and manufacturing by automakers. Those costs are passed down to the consumer, adding to the already bloated cost of buying a car.

I frequent a couple of car forums and most discussion around auto start/stop is "how can I turn this !$%?#* OFF???" Which lead to a whole new market of after-market devices to install to defeat the component. Of course, the EPA has now repealed the legislation requiring Auto Start/Stop. I'm not aware of any car maker that has stopped including the feature, or even altered it so that the driver can turn it off permanently. I have to wonder if they will bother, since apparently they are subject to any whim of the federal government changing stupid regulations at the drop of the hat (and as soon as democrats regain the majority all bets are off).

More and more, automakers are moving to hybrid vehicles that don't require Start/Stop. ICE vehicles are being totally phased out of the new vehicle market in the name of progress. We are constantly being force-fed crap we don't want, "for our own good" apparently.

In case you are interested, this guy explains the Start/Stop function and addresses some of the questions many people have. A lot of people want to know how all the starts/stops affect their engine, starter, battery, etc. and he answers those questions.

This video is 30 minutes long, but interesting if you want to know about such things.

 
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I don't know if Mazda has put that back in their cars for the US market, but when I bought my new Mazda in 2019 they had removed Auto Start/Stop in cars sold here. They retained it in other markets. My understanding with Mazdas is that when the engine turns off and you hit the gas pedal to go, it starts the car by squirting fuel in one of the cylinders and firing that spark plug...the starter is not involved.

Some cars allow you to permanently disable the feature, some required you to turn it off every time you get in the car to drive. I don't know if there are any that will not allow you to turn it off. In those cases there are "hacks" (like I had to do to disable my auto-folding side view mirrors) or after-market gadgets.

The whole thing is stupid.
 
I read somewhere that there are a couple of older model years of Chevrolet sedans that have start/stop with no ability to turn it off. I don't know of any American market vehicle that has the feature that can be permanently disabled without adding some after-market device. It's one of those aggravating things that has to be done each time the engine is restarted.

My husband's F150 was built during a time of parts shortages and the "feature" was deleted for certain Ford vehicles during that time. He was thrilled to buy a truck without it.
 
I have read some complaints about streaming stuff like Apple CarPlay or Android Auto not playing well with the start/stop. Apparently the signal is lost when the car cuts off and then there is a rebooting issue, which would really be aggravating in stop and go traffic and listening to music or a podcast. I have not noticed this in my car so I guess some car manufacturers have figured out a way around that.

The Honda start/stop is much smoother and not noticeable at all, compared to the 2024 Cadillac that seemed to "shudder" and hesitate when restarting. I never trusted that feature in the Cadillac.
 
I'm able to disable that feature on my 2023 KIA Soul/ There is a selection button I can push but it has to be pushed before I start driving.
Since I live in the city start & stop frequently my main concern was starter replacement.

The average cost for a Kia Soul Starter Replacement is between $490 and $611. Labor costs are estimated between $179 and $263 while parts are priced between $311 and $348. This range does not include taxes and fees, and does not factor in your unique location. Related repairs may also be needed.

Related repair could be the ring gear & if that were the case it would probably be cheaper to get another car. I doubt I'd save enough gas to cover that kind of cost.
 
Jose Alverez said:
I'm able to disable that feature on my 2023 KIA Soul/ There is a selection button I can push but it has to be pushed before I start driving.
Since I live in the city start & stop frequently my main concern was starter replacement.

The average cost for a Kia Soul Starter Replacement is between $490 and $611. Labor costs are estimated between $179 and $263 while parts are priced between $311 and $348. This range does not include taxes and fees, and does not factor in your unique location. Related repairs may also be needed.

Related repair could be the ring gear & if that were the case it would probably be cheaper to get another car. I doubt I'd save enough gas to cover that kind of cost.
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Welcome, Jose!

I don't think any of these vehicles use the starter to restart the vehicle. Once the engine is warmed up, there are ways the computer can get it running again by controlling fuel and the spark plugs. It's sort of amazing and stupid, all at the same time.
 
John Brunner said:
I don't think any of these vehicles use the starter to restart the vehicle. Once the engine is warmed up, there are ways the computer can get it running again by controlling fuel and the spark plugs. It's sort of amazing and stupid, all at the same time.
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Er, no. The engine must be cranked to restart it.

The last car I had with this was a Civic Hybrid that I bought in 2002 and rove for nearly 16 years before I hit a deer at night and totaled it.

There the gasoline engine and the electric traction motor were sort of integrated. The electric motor basically replaced the engine flywheel. In that case, auto start/stop restarted using the traction motor instead of a starter motor.

In a non-electric drive train there isn't much choice. The starter motor is required on restarts.
 
Jacob Petersheim said:
Er, no. The engine must be cranked to restart it.

The last car I had with this was a Civic Hybrid that I bought in 2002 and rove for nearly 16 years before I hit a deer at night and totaled it.

There the gasoline engine and the electric traction motor were sort of integrated. The electric motor basically replaced the engine flywheel. In that case, auto start/stop restarted using the traction motor instead of a starter motor.

In a non-electric drive train there isn't much choice. The starter motor is required on restarts.
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Mazdas don't crank to restart. "Unlike conventional systems, which rely on a starter motor, the Mazda i-Stop system uses a unique combustion method to restart the engine. This method injects fuel directly into a cylinder while the engine is off, creating downward piston force. As a result, you enjoy a faster and quieter restart."
link

I guess it's sort of a "bump start" method. Mazdas have been doing it like that for years...long before I bought my 2019 CX5. And now I see that (for better or for worse) i-stop has been brought back to the US market.

I guess I was wrong to extrapolate that to other makes. With everything controlled by computers, it seems stupid to overtax a mechanical starter like that.
 
That seems pretty wild.

The description doesn't make much sense. It seems as if on "stop" the engine would need to be very hard-stopped at the very end of the compression stroke of the "victim" cylinder, then hold that compressed mx of fuel and air until "start" triggered the combustion via spark.

I can't see hoe injection helps ANY of that happen.

Something sounds very wrong to me, but I'm no mechanic.
 
Jacob Petersheim said:
That seems pretty wild.

The description doesn't make much sense. It seems as if on "stop" the engine would need to be very hard-stopped at the very end of the compression stroke of the "victim" cylinder, then hold that compressed mx of fuel and air until "start" triggered the combustion via spark.

I can't see hoe injection helps ANY of that happen.

Something sounds very wrong to me, but I'm no mechanic.
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I wondered the same thing about stopping the engine at just the right spot, unless the car's electronics sense piston position (and I guess they have to in order to adjust timing) and pick whichever one is closest to "just past" TDC. But even then, could the injection system really apply enough pressure to turn the engine? My cursory search only found that one article that described how it functions rather than how to use it, so it might just be one author's opinion.

I'm sure I read that their legacy i-stop system did such "pick your piston" sensing and used a bit of fuel and the spark plug to bump start it. And it sucks that the US is now burdened with it again (articles infer that it returned in MY2025.)
 
Beth Gallagher said:
I frequent a couple of car forums and most discussion around auto start/stop is "how can I turn this !$%?#* OFF???" Which lead to a whole new market of after-market devices to install to defeat the component.
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After reading dozens of posts on several car forums, I decided to buy an "Idle Start/Stop Eliminator" device for my Honda. I've had it for about a month but I was nervous about installing the thing. I have a grandson who is a certified mechanic (works for Toyota) so I asked him if the device would hurt anything and he said no. When the vehicle turns on, the device sends a quick data pulse that mimics the signal of pressing the physical button, automatically toggling the feature off (or something like that. 🤡)

So I told my husband "today is the day" and went out to the garage with my trim tool to pop the cover off the console. Naturally he followed me to 'observe' and ended up with his head and hands in the big middle of the operation. (Works every time.)

We taped off the console area so we wouldn't scratch anything, then popped the trim piece off where the gear shift and other buttons are located. This was the hardest part but we managed to get it off without messing anything up. The Start/Stop Eliminator is simply plug and play, and then the trim piece just snapped back into place. It works!! littleb.gif

Took 2 old people about 10 minutes to install, and so far everything still works as it should. Except the Idle Stop/Start. Yay.
 
We have it in our 2021 Dodge Durango GT, but we shut it off (on/off switch on the dash). The battery for it ended up going bad and we'd get a Warning Signal on our dash every time we'd start the engine. Had the battery replaced last week and the Warning Signal doesn't light up now. IOW, there is a separate battery that operates the "Stop N Go", from the main battery. The "Stop N Go" battery is pretty small and not in the same location of the main battery. Have read many complaints about the "Stop N Go" in that it can/will ruin the starter.
 
Cody Fousnough said:
We have it in our 2021 Dodge Durango GT, but we shut it off (on/off switch on the dash). The battery for it ended up going bad and we'd get a Warning Signal on our dash every time we'd start the engine. Had the battery replaced last week and the Warning Signal doesn't light up now. IOW, there is a separate battery that operates the "Stop N Go", from the main battery. The "Stop N Go" battery is pretty small and not in the same location of the main battery. Have read many complaints about the "Stop N Go" in that it can/will ruin the starter.
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I've owned three vehicles with Idle Stop/Start and none of them had a battery that operated the stop/start. My Honda manual says that the feature won't work if the regular 12 Volt battery is low but that's the only mention of a battery.
 
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