Skip to main content

Disabling Your Vehicle’s Stop-Start System – Legal Or Against the Law

There are ways to permanently disable stop-start systems. We asked the EPA if it was legal to do so.

Do you despise your car's stop-start system and want to disable the darn thing – permanently? Sure, some car makers allow you to turn it off. But the system comes back on again every time you restart the car. What we are talking about is a permanent override. Where there is a will there is a way. We have heard many ways to disable the stop-start systems in today’s new vehicles. Some are mechanical, some electrical in nature. It’s tempting to just kill the darn stop-start system. But is it against the law to do so?

EPA and the Clean Air Act
The Clean Air Act has something to say about disabling any part of your automobile that has to do with its emissions. Tampering with the emissions control systems once a vehicle is certified for sale is a big deal. The fines for doing so are in the thousands of dollars. Per vehicle. VW did it recently. After billions in fines and even jail sentences we thought we’d never hear anyone try that again. Then FCA America settled a suit over the same type of issue. These are corporations who act on a much larger scale than just you me and our local mechanic. But is the law any different for us regular Joe’s?

Not the way we read it. It seems pretty clear that tampering with the emissions controls is a no-no regardless of who does it. Here is just part of what the Clean Air Act law says, "...For any person to remove or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this subchapter prior to its sale and delivery to the ultimate purchaser, or for any person knowingly to remove or render inoperative any such device or element of design after such sale and delivery to the ultimate purchaser; or (B) for any person to manufacture or sell, or offer to sell, or install, any part or component intended for use with, or as part of, any motor vehicle or motor vehicle engine, where a principal effect of the part or component is to bypass, defeat, or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this subchapter, and where the person knows or should know that such part or component is being offered for sale or installed for such use or put to such use..."

The law seems pretty clear. However, we are not EPA experts. So we asked the EPA experts. Let us be clear here that this story is not meant to cast the EPA in a poor light. The media relations team at the EPA is super responsive, and always happy to help us when we request it. We reached out by both e-mail and phone. We asked the EPA if disabling a stop-start system would be considered a violation of the Clean Air Act or any other environmental regulation. We also specifically asked for some guidance on individual owners working alone, a local mechanic who charges to perform a stop-start disable service, a company that provides an override product for sale, and an official new car dealership offering such a product or service.

EPA's Opinion On Stop-Start Disabling Legality
In total, seven employees of the U.S. Environmental Protection Agency joined the communication chain. The U.S. EPA’s New England Regional Office of Public Affairs took the point position. After three days of consideration of the question here is the answer we received:

“The EPA generally does not allege conduct to be illegal unless and until the agency has developed a factual basis and decided to pursue an enforcement action. To determine whether conduct amounts to illegal tampering or whether an aftermarket product is an illegal defeat device, the EPA would first need to investigate whether each element of the statutory prohibition has occurred. With regard to a start/stop system, for example, before alleging any violation the EPA would need to determine first whether the manufacturer of the vehicle in question used the start/stop system to comply with the applicable regulations concerning emissions. If so, removing that system or rendering it inoperative may amount to illegal tampering, and aftermarket parts and components that bypass, defeat, or render the system inoperative could amount to illegal defeat devices. To date, the tampering and aftermarket defeat device cases EPA has resolved have generally included the complete removal of filters and catalysts that are essential for controlling emissions of oxides of nitrogen, particulate matter, and other tailpipe pollutants.”

Hmm. Certainly not a green light to go ahead and defeat that stop-start. Also certainly not a definitive, “Yes, we will send the SWAT team over if we find out anyone does this!” More along the lines of, “We are not really sure the stop-start even qualifies as an official emissions control system. And we are not really sure we would jump on that if it was.” Our paraphrasing is not meant to be disrespectful.

Here’s our guess as to what would happen in three specific groups of scenarios:
1) A Vehicle Owner Disables The Stop-Start System On Their Own
It is hard to see how you would ever get caught unless the state you live in has an annual smog check during which they tap your OBD port and look for codes. In my state of Massachusetts, if a code is found and relates to the emissions system the inspection is a fail. This according to mechanics who perform the inspection we spoke to. The vehicle will be passed once the issue is solved and the code “cleared.” If you live in a state without emissions testing, who would ever know? Well, maybe your dealer if any warranty work is needed. O2 sensor needs replacement? Catalytic converters shot? Starting system problems? Don’t expect coverage if you’ve tampered with the vehicle’s stop-start system.

2) A Company Develops, Offers For Sale, and Sells A Universal Stop-Start Device
Our guess in this situation is that the EPA would take notice. Also, stop-start has value to automakers. If it isn’t available to them, they have to earn a higher EPA average and that is now getting very hard to improve upon without spending money. No automaker wants to make defeating stop-start too easy.

3) A Dealer Offers to Disable Your Stop-Start System
Here again, we think the EPA would take quick notice. Dealers act as official agents for the maintenance of emissions systems. We seriously doubt any would be bold enough to do this, but if they did, we’d expect a confrontation with some agency to germinate.

Conclusion: Is It Against the Law To Disable Your Stop-Start System?
Our opinion is “yes, it is illegal.” Just like removing your catalytic converter or using software to over-ride an emissions control system. Will you get caught? Doubtful.

John Goreham can be followed on Twitter at @johngoreham.

Torque News would like to thank the EPA for its assistance in the creation of this story.


Chris (not verified)    July 11, 2019 - 2:09PM

Yes, it is illegal? And you come to this conclusion how? This is a manufacturer added gimmick, not created to satisfy any EPA reg.

John Goreham    July 12, 2019 - 4:46PM

In reply to by Chris (not verified)

Note the law's wording about what cannot be removed or rendered inoperative. "..any device or element of design installed on or in a motor vehicle or motor vehicle engine." The individual systems in a vehicle are not the "EPA reg." The vehicle's emissions system is certified as a whole by the EPA. As an entity. By VIN. Stop-start reduces the grams of gases emitted per mile driven. I came to the conclusions I present by researching the subject and then by communicating with the EPA directly.

WILLIE A STURGEON (not verified)    April 30, 2021 - 6:06PM

In reply to by John Goreham

Well the real problem car engines are jot designed start and stop all the time .most of damage that happens crankshaft and bearing happen at a start up and u wonder why these small motors don,t last more than 100,000 miles with out problems manufacturers like gm and Ford and dodge don,t care if there sorry ass little turbo motors don,t last and long they sell dumb people cars

Chris (not verified)    July 12, 2019 - 4:51PM

In reply to by Chris (not verified)

This may have been run by the EPA when chasing CAFE, but the fact it can be disabled by the driver during the drive does not make it a binding EPA system like a catalytic converter. I disabled mine and wrote to the EPA. We will see where it goes. But any lawyer who could pass the bar could abate this situation.

Jesse (not verified)    July 12, 2019 - 3:36PM

If it illegal, why then do auto manufacturers offer a defeat switch on the dash for such purpose? The new Ford Ranger that just came out, well it has an automatic defeat for the stop/start when the truck is in 4 wheel-drive mode or when pulling a trailer....per Ford's own add copy. It is a gimmick for two reasons: 1) When a vehicle isn't running it produces no emissions, and 2) It uses no gas, which refers us back to reason 1.

John Goreham    July 12, 2019 - 4:42PM

In reply to by Jesse (not verified)

Excellent question. Because the switch is not "latching." Meaning that when you restart the vehicle, the switch defaults back to its "on position." The EPA offers automakers varying incentives for non-latching versions of Stop-start and versions that have no switch at all (Chevy Blazer for example). Vehicle emissions are measured by the EPA in grams produced per mile driven. Stop-start reduces emissions. If you prefer to see it as a gimmick that's cool with me. Solar-reflective glass, certain refrigerants, and many other technologies earn automakers points towards their CAFE requirments. These gimmicks help enable the availability of V8 powertrains in cars like the Chevy Camaro and Mustang GT. I'm not advocating for these, I'm reporting on them.

Chris (not verified)    July 12, 2019 - 4:44PM

John, your reporting is timely, that’s not my concern. Legality is. The EPA is not one to f with. Therefore, opinions not based in fact are just that, opinions.

Marcella Castellon (not verified)    July 13, 2019 - 3:20AM

I bought my vehicle and the switch doesn't work. My car has been running bad, I have a device called SYNCUP that stays plugged up in my car. It tells me if something is wrong with the vehicle. I'm getting the message that emission system has a leak. I brought it back to dealer and they say nothing is wrong with my car. What should I do. Please help!!

Jesse (not verified)    July 13, 2019 - 2:36PM

Marcella, did you recently fill-up? If you did and then the engine started running badly, it could be the gas. Area auto stores usually will check you OBD (onboard diagnostic) to see if you have any codes stored. Is your check engine light on? We have Auto Zone, Advance Auto, and O'Reillys in the area that will check for stored codes. Around here they do it for free. I went by Auto Zone once for this service. They found a code....luckily I just needed a new gas cap. You might swing by an auto parts and ask if they have this service and if it is free. I like to do the easy stuff first. Have you checked your air filter? Also, any loose vacuum hoses may cause a rough running engine. Good luck!

Ray Jensen (not verified)    July 15, 2019 - 7:08AM

SO....let me get this straight. A major manufacturer like Kia or Honda provides auto stop-start "temporary" disable their cars. You get in the car, start it, HIT THE DISABLE BUTTON......and VOILA! NO AUTO STOP START. can't permanently disable it? WHAT THE HELL IS THE DIFFERENCE? WE'RE BEING DUPED.....AGAIN. Auto STOP just a CHEAP way for the manufacturers of loose engines to meet EPA guidelines....sort of. Auto stop start sucks, it is bad for your car, it WILL cost you money in the long run......and it NEVER should have been installed in ANY car. My opinion.

Mark C (not verified)    October 19, 2019 - 1:01AM

All the start/stop does is give auto manufactures BS credits for emissions and economy. the difference is so insignificant its ridiculous. If you take 2 exact same cars, side by driver uses the start/stop, but drives it like they stole it, the other turns the start/stop off but drives it like a little old lady going to church. Now you tell me the one with the start/stop on, is going to get better mileage and emit lower emissions than grandma. Total BS and al it does is make the tree huggers feel better about them selves. I suspect grandma will still have enough gas to get the gas station in the next town while the other is sitting on the side of the road......out of gas. THINK ABOUT THAT Mr. EPA !!!!! Regulating the weight of ones shoe would have far more effect than this crap.

Brian (not verified)    November 22, 2019 - 9:19PM

I interpret it as saying that you cannot remove the switch. Having a device that automatically switches it to off each time is fine so long as the switch is still intact and functioning.

ed breyer (not verified)    February 12, 2020 - 7:33PM

In reply to by Brian (not verified)

Plus even if an EPA bureaucrat claimed it was illegal to over-ride - WHO CARES?! They will never know I did it. I had to disable the VCM system on our Honda Odyssey because shutting down cylinders was causing engine damage. I and thousands of other Ody owners installed devices which prevents the VCM system from engaging and we couldn't give a cr@p what the EPA says about it - they aren't paying our repair bills!!

John rock (not verified)    November 30, 2019 - 10:32PM

The wording specifically states any modifications before delivery to the ultimate purchaser or for anyone to manufacture an item to defeat the system. So the ultimate purchaser can legally do anything they want to the system. Now, after they do, it may not pass the individual state inspection, but it is not illegal.
If you are selling a device or offer a service to disable the system that’s illegal.
But when a system clearly has safety issues, causes undo hardware failures, or causes mental anguish, the system should be illegal itself, and there should be a way to permanently disable it.

JohnIL (not verified)    December 14, 2019 - 10:45AM

At least on my 2018 Ford F150 I have a switch to deactivate it but I have to select it every time I start up the engine. Obviously however the vehicle was certified by the EPA means that you cannot defeat any of those emission features. This applies to the start stop technology. GM by 2020 will have a non defeat start stop which you cannot override. It's definitely why I won't buy a GM vehicle ever again. We all used to be told that frequent starts and stops wear out engines more than anything. Now all of a sudden its perfectly fine which I call BS. It's just because the manufactures get a break on Cafe standards by implementing this. They could care less if your engine wears out faster, or that your starting system will require more repairs.

John (not verified)    December 23, 2019 - 11:14PM

I will defeat the start/stop in my 2020 Terrain Denali......until I do I just put it in L9 and the start/stop does not happen.

AKK (not verified)    January 13, 2020 - 12:15PM

On GM's if you pull the connector that is in line with the hood latch sensor, it disables STOP/START. System logic shuts off stop/start if the hood is open, so you "trick" it. The only downside is the check engine light stays on. Minor inconvenience. When you go to dealer for service, reconnect the connector and no one's the wiser.
The aftermarket modules plug inline on that wire harness and do exactly what pulling it does, except they also turn off the check engine light. That benefit cosses you about $150 bucks for the module.

ky (not verified)    June 13, 2022 - 9:57AM

In reply to by AKK (not verified)

that connected device. is a wire that carries the sensor's signal cut off. They sell it for 25 dollars which is too expensive. The sensor consists of 3 wires. 2 strands carry positive and negative charges. if you cut them off, the meter will say sensor lost. when you cut the 3rd fiber that carries the response signal. Your car will not report an error. and auto start stop will be completely lost

ed breyer (not verified)    February 12, 2020 - 7:23PM

Interesting observations. But these systems are designed to improve EPA mileage ratings not necessarily reduce total emissions. But why should I care? I own the car and am not going to put up with an annoying system that some mechanics are claiming resorts in premature wear to several components - including timing belts/chains. My Honda Odyssey had a VCM system that shut off cylinders on the highway to save fuel. Unfortunately it caused expensive engine repairs - so I and every Ody owner I know have installed devices that disable the VCM system. I have absolutely no concern that the EPA is going to come knock on my door - and would tell them where to go if they ever did. Some of us don't blindly obey every inane regulation that comes out.

J Little (not verified)    July 23, 2020 - 12:43PM

I almost bought a CRV with auto stop. But I hate that feature and would like to hear of ways to permanently turn it off after a purchase. To use their button each time I start it is crazy..

Gary Gottschalk (not verified)    September 25, 2020 - 1:07PM

It would seem to me that if there is a possible Clean Air Act from turning off the system that the manufacturer is complicit by installing a temporary shut off. That sounds like a Class Action lawsuit to me. They should start opening their purse strings.

Dwight Looi (not verified)    October 29, 2020 - 11:00PM

It is NOT ILLEGAL to modify your car or sell modifications for cars that REDUCE THEIR FUEL ECONOMY. If that is the case, a trailer that adds weight, stupid wings that increase drag or stickier tires that increase rolling resistance would be illegal. It is totally legal for manufacturers to sell cars without idle stop systems and it is totally legal for you to disable it. It is NOT an emissions control device. It is a fuel economy feature that is neither mandated by the government nor affect your exhaust gas composition in any way.
The reason many manufacturers do not offer a way to disable idle stop or have it revert back to on when the ignition is turn off is that the EPA will only include the idle stop benefits in the window sticker MPG figures if it is always enabled or reverts to enabled. Hence, the manufacturer cannot claim the same window sticker EPA mpg numbers unless they do so or benefit from the small CAFE ratings benefits it brings. However, it is totally legal for the manufacturer, dealer or any 3rd party to sell, or offer for free, an after sale modification to disable the feature -- just like it is legal for them to sell you a fuel economy reducing device a spoiler, sporty tires or a trailer hitch.

Davy Crockett (not verified)    February 17, 2021 - 3:08PM

This is the worst ideal known to mankind

I did not know about this switch until today. I was making a hard and fast right turn due to incoming traffic, the car hesitated and made a clunk sound, it cost me about a second and I had incoming traffic. Scared me to death.

But i can turn it off. I want to disable it

darrell coleman (not verified)    April 14, 2021 - 3:40PM

i was harasted an had my car disabled while driving an witness police helping tow companies i want o know what can i do about it

Robert J Guilliams (not verified)    May 13, 2021 - 3:59PM

Besides being hard on the engine, what about the starter motors? Just ask your local mail carrier how often they have to replace the starter motors in their vehicles (mine said about every 6 months). Sure, the manufacturers warranty will cover it initially, but ... what about after warranty expires? Just a stupid idea. Trying to figure out how to fake it into thinking I'm towing a trailer.