In the USA with the easing up of the EPA regulation the adjustments in the ECU can actually create an improved MPG even with the increase in weight.
In reality a ECU programing like Versa Tuner on any Mazda they offer you can improve both power and MPG and still be under the EPA requirements for the time before the EPA regulation were just reduced.
I created a couple of specific target ECU files that do just that and are under the HC and CO readings at the tail pipe that could easily pass any states tailpipe test.

But you all will have to wait for a little longer because no one offers' a program yet for the newer Mazda's CX-5 with CD 2018-2026
VersaTuner

 

i find posting "welcome to the forum" in a first post where a user is looking for info to fix their car a waste, but i guess it helps pad the post count...ahh yes courtesy, courtesy must be why you've been banned from other vehicle forums by admin/mods...funny that you think i would actually spend the time to search and count the actual number of times you welcomed people lol...but i'm sure that most people agree with you that car dealerships trustworthy lol...anyway, carry on denying reality about i-stop and cylinder deactivation being installed on the 2026 cx-5

 

>>>>>>>

 

Just a few words regarding Cylinder deactivation.. Having purchased a new Mazda CX-30 Exclusive Line , March 2026 I can confirm that this vehicle has cylinder deactivation installed and verified by Mazda UK who say that provided that no error codes exist and correct driving pararmeters are met the system will work. The vehicle was built Februrary 3rd 2026.

 

You can only verify if YOUR Mazda has any specific feature , not globally of complete model without using that VIN on each vehicle.

 

wait a minute,your a certified mazda technician-is it because you are independent you can be a member?
either way...very cool....now i see people have varying opinions on cylinder deactivation and you may have given insight on this forum before but
can you please give your opinion,is it something to not think about because its like an iron curtain that can't be penetrated or as soon as there is a delete
patch available take it.
I see you had abilty to check mazda info and found nothing -no failures related to the deactivation,have you ever seen any problems at your shop? thank you

 

I am an independent certified ASE Master Automotive Technician for over 3 decades. In my area like many in the world many auto manufacture like Mazda do not require to employee an individual with a level like me to be employed in the service department. Some dealerships have a "factory trained " service individual. These are mostly a person that already has some training background and credentials in auto mechanic of years of hands on practical experience. In the case of Mazda they have a position ranked as the highest level in service as a Mazda factory Trained Mechanic. We are lucky one of these are a member of this forum and an active one at that! No its not me. LOL.
Near my location are I have 3 local Mazda dealerships within 50 miles or less of each other and my location and the location of the service shop I manage. Occasionally they get a WARRATY related issue that they don't have a qualified or enough service people to handle the normal service work and some warranty services. So I am contracted independently but not through the shop I work for to perform a warranty service. I have a good arrangement with the shop I work with to be able to use a service bay to do the work for a fee I pay the shop. lol Besides most of my shop tools are there in the shop and not easily moved around from one location to another. And my service people get to actually see me get under a hood (so to say) and do service work and get my hands dirty. LOL By some federal law I can do warranty on all but a safety recall service? Which this is in itself funny because I can inspect another persons warranty service work done for a safety recall but I cant actual do the safety recall service??? Politics'.

Ok so cylinder activation ...I don't dislike it but for me my life over decades has been so trained to hear, see and feel things when they go or start to go wrong. On an electric or Hybrid vehicle I just don't get enough of them in the shop to acquire a working knowledge of all the issues and such to know where the problem is or where a problem is starting. And I have decided NOT to go to a trade school learn about them and then test for an ASE l3 certification. This would cost me several thousand dollars. At my age not interested. As for cylinder deactivation I have yet to tear down an engine that had cylinder deactivation and used considerably in that setting that went 100k or more miles to see the effect of that engine going to that point what wear the reciprocating assembly had happen and to what extent. I have read a few technical articles, but they are all theory. Even then it would require to actually have a level of information for me to tear down and inspect a dozen or more high millage engine using cylinder deactivation to have a base line of service wear information? I can at least at this point in their development and use state that there will be negative effects on any engine that is cold started and immediately used. This is just physics of the different rates of material expansion rate when heat is applied to them when they are cold. .

 

Sometime you got to get a little wet to make things clean in hard to get places.

post #383 and 384. To name 2 of several cleaning tasks done on the under carriage chassis, suspension , brake system and engine over the years on a Dailey driven Mazda 2018 purchased in November of 2016 with less then 3 miles on the odo now with 68k miles on the odometer. This is NOT a hobby or project car as I stated it is very much a daily driver. Got the chips all over to prove it. lol

Mazda3 Things I like to do - Mazda Forum - Mazda Enthusiast Forums

 

In my 2025 i watch the CD display often. It definitely does not activate until the temp gauge gets over about 160F.

I do worry about it. Decided frequent oil changes and transmission fluid services are my best insurance against this system causing excess wear.

So i am one of the "didnt know until after I bought it" folks. There are times its seamless but times it detracts from driving via the subtle little shifts in engine power. What I think makes by far the best sense is if Mazda would reprogram this to allow it to be toggled on/off via the menus.

Meanwhile can I ask what this is on my engine (see photo)... some kind of EGR cooler?. I dont see that on other shots of the 2.5L skyactive where the intakes are more visible.

And my engine cover is smaller too.

 

Yes that’s what it is. IMHO another Hail Mary attempt to comply with some countries EPA regulations pertains to the HC and CO exhaust outputs. It is IMHO another bad idea and is countering acting other engineering engine operations. But I don’t want to get into that, I can suggest it was an afterthought.
I looked at some the ECU programing published and it’s ridiculous….IMHO. Current Mazda has many of their latest ECU programs under proprietary protection even if you are a Mazda corp powertrain engineer.