2016 front wheel drive 2.0 skyactive cx5 with a small but anoying problem
 

Greetings from panama.

I had replaced the oem battery with a d35 yellow top optima about 2 year ago. Long story short... i just placed a bmw agm battery on the car, yet the istop still non functioning and the "battery management issue" still on display..

the new agm measured 12.5 volts when i placed it in... with the engine on, it does measure 13.7... (i read somewhere that when the batter is fully charged it wont go over 14 volts)...
anyways... battery does measure 12.7 V now. and i still can't reset the danm istop. (i did it several times following the istop off switch long pressed then turning the engine on etc).

i even left the car over half hour with the negative terminal off... then try the istop reset thing... also did the 20 gas pedal down thing to reset ecu... still having the same issue.

its driving me nuts.

AGM and "Wet" batteries have different charge and discharge characteristics; if your CX-5 came from the factory with a wet lead-acid battery, then the odds are it was designed specifically for that type of battery. Long story short, the AGM battery may never work in your car.

with all due respect bro..

I checked the logs... the d35 was installed in august 29, 2017.... so how come the system worked for nearly 2 years without any issue?

Optima batteries are not what they used to be... plus, me being in latin america... the one i got was made on Mexico. Maybe the issue is/was that i took about 3 weeks to change it as i was getting an bmw branded AGM

You missed the point; good luck with your battery.

Have you ever noticed that when someone says "with all due respect", respect seldom follows?

I have found shipo's input to typically right on the mark. If someone doesn't like a given response, they are free to seek advice elsewhere.

Do you understand the special construction of the the factory Q85 battery? It was fitted for a reason to allow full, propper and long term operation of the i-stop system. Failure to utilize a stop/start designed battery, ie the Q85 will result in operation errors and failure.

No other battery is designed for the long term operation demands of the i-stop system.

If you want a correctly operation i-stop system, get a scan tool, clear the fault codes ( namely P0A8D), then remove your old incorrect battery,disconnect the voltage sensor off the negative terminal, wait 5 minutes or more, fit the correctly specified Q85 battery, wait 10 seconds, fit the voltage sensor, close the bonnet and then carry out the i-stop relearn procedure as per the workshop manual.

Yes I know what I'm talking about. I've been working for Mazda for the last 13yrs.

any recomendation on a cheap yet suiatable scan tool ?

I have to deal with the guy who sold me the battery... these AGM wasn't cheap.

Pretty much any scan tool that's capable of clearing codes will work.

Assuming you care, the battery is fine.

odb2 computer where used to clear about 6 stored codes including P0A8D...