How to reset the i-stop system (eg after battery replacement)

:
CX5 Akera 2.2 Diesel
On CX5s and other Mazda's with the i-stop system, i-stop may not activate after the battery has been replaced or was disconnected during some servicing.

In this case you will either need to ask your dealer to reset it, which they can by connecting up to the diagnostic system, or you can do it yourself.

I found some instructions for a MZR 2.0, but it worked very similarly, as below, on my CX5 2.2 diesel.

1. Warm up the engine. Turn everything electrical off that you can - radio, A/C etc so there is no/minimal electrical load.
2. Switch the ignition off.
3. Switch ignition to on but dont start engine. Long-press the i-stop OFF switch for 3 s within 5 s after switching the ignition ON.
4. Start the engine.
5. Press the i-stop OFF switch. Verify that the i-stop indicator light (green) flashes and stays flashing. If it does not flash, go back to Step 3.
6. Allow the engine to idle for 10 minutes, or until the i-stop indicator light (green) turns off. Mine didnt stop flashing so after 10 minutes or so i just went to step 7.
7. Switch the engine off. Wait a minute or two.
8. Start the engine. Go for a drive, and check that the i-stop system operates normally. Those with i-stop will know that you may need to drive a mile or two until it activates. Remember that i-stop will not operate when (a) diesel engines are in regen mode, and (b) in some other conditions - see your manual for details. Also, if a new battery was fitted, it may take some time for the new battery to fully charge up before i-stop will start working. Go for a decent drive so it gets fully charged.
9. If i-stop operates as normal, you have successfully reset it.

Cheers!
 
Thank you for the write-up! We don't get excellent and unique i-stop here in the US and we can only hope someday we'll need your write-up when Mazda North American Operations decide to add this feature for us under the competition as Honda has put Idle Stop system into Pilot for US customers.
 
Just curious as I'm just about to replace my battery.......If I DON'T do the above reset will that mean the annoying istop will be permantly switched off? 😉🤔
 
Just replaced my battery and weird thing is I didn't have to reset, istop magically working normal again after 2 hrs drive.
By the way my battery was completely dead couldn't lock the car with the remote.
 
Just replaced my battery and weird thing is I didn't have to reset, istop magically working normal again after 2 hrs drive.
By the way my battery was completely dead couldn't lock the car with the remote.

You have a US spec car with I-stop?(confused)
 
As per my original post, iStop MAY not reset itself after a battery replacement.

It may also reset itself, as yours obviously has. Lucky you!

I guess you fooled us, since your location says USA.
 
did you replace your battery with ORIGINAL battery type or after market? dealer said aftermarket batteries wont work..

replaced it with optima yellow top.

you could use ordinary maintenance free or even low maintenance automotive battery but from what i've read it would not survive that long because of the killer start/ stop feature.

the EFB battery that came with the car didn't last 2 years. trying this AGM battery see how it would last
 
you could use ordinary maintenance free or even low maintenance automotive battery but from what i've read it would not survive that long because of the killer start/ stop feature.

Do you know how the “killer” Mazda iStop system works?
 
that's what i've read in articles and discussion on the net.

Do try a ordinary maintenance free battery on your mazda with istop and tell us how it holds up
 
Last edited:
that's what i've read in articles and discussion on the net.

Do try a ordinary maintenance free battery on your mazda with istop and tell us how it holds up

Since you read it on the net, it must be true. Naturally.

I am on my second CX5 diesel, both with iStop feature.

They both came fitted with Mazda’s OEM Panasonic flooded cell lead acid (EFB) battery, not even a maintenance free models, so (surprise surprise!) you need to regularly monitor and top up the electrolyte level.

Funnily enough, Mazda specifies such a EFB battery due to its enhanced design that is designed for repeated starts inherent in stop/start systems. Its not a standard flooded cell battery, nor is it an AGM.

First was a 2013 GT that I had for 3 years and over 90,000kms. Battery never missed a beat in that time. But I did take care of it by topping up the battery every few months.

Current CX5 Akera is the top of the line model with every electronic option and system available, so max possible demands on the battery. Not doing as many km on this one since I retired but its now 18months old and 25000kms. Same battery model as first car. Again I keep the battery topped up as it should be.

So yes, I can tell you that a EFB flooded cell lead acid battery, as fitted by Mazda, even one requiring owner maintenance, does a sterling job and Mazda’s clever IStop system hasnt killed the battery.

You might want to have a read about what some leading battery people say about replacing batteries in stop/start cars:
https://www.yuasa.co.uk/info/technical/start-stop-vehicle-battery-replacement-warning/

I am doing some further research about replacing the Mazda EFB battery with AGM, because I am seeing lots of battery companies saying only to replace like-with-like. Eg that you should replace EFB only with EFB.

I have asked my auto association for their technical advice in this regard and will post back with their response. Their default advice on their website is to replace EFB only with EFB.
 
Last edited:
Since you read it on the net, it must be true. Naturally.

Hahaha you must be itching to respond with this, don't you? your reference link is also from the net, your statement above is now on the net too! you must be this special kind of human that they talk about.

panasonic n-q85 on their website states its a maintenance free =) here's the reason i went with optima, optima cost around $340 with shipping (it's the only agm i could easily procure). the mazda dealers' replacement deep cycle efb battery cost around $300 plus installation charge and it's not the panasonic q85 rather it's made by local brand here which i had bad experiences even on their top tier maintenance free advertised as tropicalized battery.

Good for you that your battery last longer than usual and if you shared this knowledge of topping it up with distilled water then i might have thanked you.

I never asked you about this, you did and you answered it yourself, good job mate!
 
So youre saying you never topped up your original Panasonic?

The little screw caps on the top of the battery are somewhat of a giveaway to most people.

Expensive lesson there.

Sounds very much like the battery killer isnt Mazda iStop, its the operator (poke):D
 
Last edited:
So youre saying you never topped up your original Panasonic?

The little screw caps on the top of the battery are somewhat of a giveaway to most people.

Expensive lesson there.

Sounds very much like the battery killer isnt Mazda iStop, its the operator (poke):D

Never 'cause what part of maintenance free battery you don't understand? and yes i did checked it once it got bad and levels where fine.

Wohooo so moonlighter have conclude its the operators fault specifically me, Driver 1 yey! brilliant conclusion moonlighter even though he doesn't know the weather conditions in the Philippines and traffic situation.

Hey you're retired right so you have time and i hope you have money even though you could only afford mazdas, why don't you visit the Philippines rent a mazda with you're precious non battery killer istop feature and drive around the metro and tell us how many times does the istop activates per day. 'cause as you imply the mazda istop does not and never cause strain to the battery 'cause its sooo cleveeer. its the water level and drivers fault, bad water level bad driver!

I never understood why you got mental when i stated istop is a killer hahaha but i loved it never had this fun in years on a keyboard.
 
it's not always a simple matter of electrolyte level in the battery that can cause premature failure, although it isn't a maintenance free battery nor Mazda USA explicitly says is a maintenance battery in the shop manual, but is implied so based on the many pages dedicated to the "w/i-eloop" battery pages in the USDM 3's and 6's shop manuals ... based on the Japanese article I've read on Kowa Seiki's website (full of sales pitches, because they're selling the product), they've seen high failure rates of the idling start-stop (aka EFB) batteries at dealers all over Japan, not just Mazda, although Kowa Seiki is officially Mazda's tool supplier. The article claims that in collaboration with CTEK from Sweden, they determined that the battery failures are caused by acid stratification and they have released a special CTEK charger that can remove this acid stratification. They claim that after some dealers started using this $1200 CTEK charger, their warranty claims on the Panasonic or Yuasa batteries have dropped greatly and they've seen the battery life go from just a little past a year to 3 years average. Acid stratification causes specific gravity issues, and thus, false state of charge is detected by the i-eloop/i-stop system's current detectors. This false state of charge detection, can cause under or over charging issues with the battery, leading to cell damage. The acid stratification is exacerbated because the constant deep cycling caused by heavy battery usage from idle start-stop use. And when the battery is undercharged, cell plate sulfation results, which causes the battery's capacity to be reduced, and eventually cause failure. Half of this stuff isn't mentioned in the shop manual, which is pretty interesting.

That $1200 JDM only CTEK charger has claimed advanced "ISS battery refresh" function that's not in the cheaper JDM models.... whatever, I can't afford a $1200 battery charger (if I ever come across a used one for a good price, I'll buy it for sure).
What I could afford was Yuasa's own charger that has its own "ISS battery refresh" function, for a fraction of the price from Japan. It seems to behave the same way that Kowa Seiki claims their own private labeled CTEK charger does... recharge the battery at low pulsating current, to desulfate and recharge, then do a high voltage (17-18 volt), high current charge to "stir" the electrolyte. "Stir" it does... after a few hours of running the charger with the battery caps off (you must do that, in accordance with Mazda's shop manual or run great safety risk), the electrolyte is "boiling" until the cycle ends after about 8 hours on my very healthy Q-85 battery. This was one of the few affordable chargers in Japan that is fully compatible with a EFB at the time I got this early last year. Nothing in the US DIY/consumer market was fully EFB compatible until CTEK USA released their MXS 5.0 charger mid last year. There's plenty of choices from Europe as they've been ahead of us in putting out cars with start-stop features, but importing a charger from Europe meant having to get a step up transformer to run the charger, which is a pain in the ass and additional fire hazard, despite the fact that I have plenty of step up transformers.

These batteries are funny beasts... standard smart chargers and testers falsely detect the state of charge because they seem to have a very different surface charge behavior than regular batteries, so you can't fully use any regular charger with these batteries. You could use a fully manual charger, and time the charge, after using a hydrometer to check the specific gravity to calculate a state of charge (all stated how to do so in the shop manual), but that's a huge messy pain in the ass. I instead, chose to buy a battery tester that can handle EFB, which will properly give me an accurate state of charge and state of health readout digitally, and of course also the special smart charger, because this is easier and faster to do a quick do over. In any case, you must use these batteries with start-stop systems or with Mazda's i-eloop system because it has deep cycle characteristics from the denser cells, but it also can accept high current charges more easily without cell damage like a standard battery does... hence why standard batteries can't last long in cars with these systems

Anyhow, for many of you, get a European/220 volt CTEK charger that can handle EFB, with the "recondition" mode... no point getting the charger without it. For the few of us in the US or Canada that have a 3 or 6 with i-eloop, get the CTEK MXS 5.0 or import the Yuasa charger from Japan like I did, which is designed for 100 volts but works fine on 120 volts... the Yuasa doesn't really have a float charging function from what I've seen, but it does have a similar "refresh" function as the expensive $1200 JDM CTEK... but the non-JDM CTEK only has a "recondition" mode, rather than the "refresh" mode... it is still probably a better buy as it's easier and cheaper to get anyway, which makes it a more practical long term use as you can use it as a float charger on any car, including ones with start-stop systems, when you are parking the car for an extended period of time (winter hibernation or vacation, for example)...

what's the difference between the "refresh" and "recondition" modes? "refresh" does a slow ramp up to high voltage, high current charge after fully recharging the battery to force out gassing of the battery which forces the electrolyte to aggressively "stir", eliminating acid stratification completely.... this is a one step process on the Yuasa charger, but on the $1200 JDM CTEK, you must do a standard recharge or "recondition" first, before switching to "refresh" mode... "recondition" mode on the CTEK does a desulfate, then recharge, before slowly ramping to a slightly higher voltage (15.8 volts) low current charge to force out gassing of the battery to "stir" the electrolyte to remove acid stratification... on a standard battery, the "recondition" mode works fine, but on an EFB, it will either remove stratification incompletely or will take a longer time to do so, hence why the higher voltage and higher current profiles are used on the $1200 JDM CTEK and the affordable Yuasa chargers... both of these chargers will completely remove stratification on an EFB and fairly quickly... so if you want to have an EFB compatible float charger, and also have a true "refresh" mode, without breaking the bank, buying both chargers is the only way at this time, unfortunately :(

I run the refresh function once a year. But if your battery sees heavy use, twice a year is probably better... be sure to top off the level first with distilled water before running the charger, or you'll damage the battery!

attachment.php
 

Attachments

  • charger.jpg
    charger.jpg
    153.6 KB · Views: 35,679
Last edited:
Back