anyone know where and which fuse is for 2012 CX-9 ECU, failed emissions,

You failed the state inspection? was the check engine light on? You should have taken it to the dealer, the inspection is free and if you fail emissions the warranty on that is 8 yrs and 80k on emissions controls
 
If the ECU fuse is blown, the car won't run at all.

They should have told you what part of the test you failed (CO, NOx, HC, or readiness). You need to start from there.
 
You failed the state inspection? was the check engine light on? You should have taken it to the dealer, the inspection is free and if you fail emissions the warranty on that is 8 yrs and 80k on emissions controls

thanks for the heads up kornholio, which Mazda dealer do you go for free state inspections in NY ? I thought they charge the standard $46 everywhere.
 
just to help any fellow CX-9 with the same issue in the future, I failed emissions due to a bad oxygen sensor but there was no check engine light or any codes, I swapped out all four oxygen sensors and the emissions monitors became ready after two drive cycles

I highly recommend getting one of these and make sure monitors are ready before going for emissions test:
https://www.amazon.com/dp/ (commissions earned)
 
just to help any fellow CX-9 with the same issue in the future, I failed emissions due to a bad oxygen sensor but there was no check engine light or any codes, I swapped out all four oxygen sensors and the emissions monitors became ready after two drive cycles
I highly recommend getting one of these and make sure monitors are ready before going for emissions test:
https://www.amazon.com/dp/ (commissions earned)
Thanks for the follow-up. Can you tell us whether these 4 oxygen sensors were replaced under Mazda's emission warranty? These 4 oxygen sensors with labor can be very expensive if we have to replace them by ourself!
 
just to help any fellow CX-9 with the same issue in the future, I failed emissions due to a bad oxygen sensor but there was no check engine light or any codes, I swapped out all four oxygen sensors and the emissions monitors became ready after two drive cycles

I highly recommend getting one of these and make sure monitors are ready before going for emissions test:
https://www.amazon.com/dp/ (commissions earned)


this is not good guys, I failed emissions too !! this sucks, need to get this to pass in two days or my inspections sticker expires,

no check engine light or anything, just failed for monitors not ready, engine has been running rough during heavy acceleration, I can feel the whole front shake. I was stupid, should have used a cheapo OBDII reader first before going to inspection station

today, now it's too late, already in the system as a fail, now have to trouble shoot or take it to stealership, out of warranty 112,000 miles. Going to try astriuminc's post and get some cheap O2 sensors off eBay and swap them out myself, keeping my fingers cross.

2dv08zd.jpg
 
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this is not good guys, I failed emissions too !! this sucks, need to get this to pass in two days or my inspections sticker expires,

no check engine light or anything, just failed for monitors not ready, engine has been running rough during heavy acceleration, I can feel the whole front shake. I was stupid, should have used a cheapo OBDII reader first before going to inspection station

today, now it's too late, already in the system as a fail, now have to trouble shoot or take it to stealership, out of warranty 112,000 miles. Going to try astriuminc's post and get some cheap O2 sensors off eBay and swap them out myself, keeping my fingers cross.

2dv08zd.jpg

best of luck Avidien, I really hope you do get it fix, I owe you a lot for your PTU changing oil tutorial.
I bought the cheapest $20 CX-9 O2 and $77 WIDEBAND NTK sensors off ebay, OEM's run $200 EACH !!!!
swapped all 4, the front two are the easiest.

the first one is right in front and below the engine cover (MAKE SURE YOU BUY THE WIDEBAND TYPE)

the second one is to the right and below the engine cover towards the center bottom,

the third one is tough (it's behind the air intake plenum where the 3 hard to replace spark plugs are, again WIDEBAND TYPE)

the fourth one is by far the hardest to reach (its by the passenger wheel just inside aft of the catalytic convertor)

these are the ones I got for 2013 CX-9
http://www.ebay.com/itm/380915882205?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT
http://www.ebay.com/itm/122022870589?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Emissions are the worst, all mechanics say is you disconnected your battery and erased your emissions readiness and "keep driving" the computer needs a lot of drive cycles to set, WTF, I didn't disconnect the battery. I drove like 500 miles and it wouldn't set, I knew it had to be one of the sensors, but stupid computer didn't throw any codes. Anyway, swapped all four and they finally set, I think one of the sensors was faulty and I was running rich (very low MPG and rough engine with noticeable less power than usual) not good for catalytic convertor, running rich fuel to air ratio will damage the cat and that's like $2000 to fix! http://repairpal.com/estimator/mazda/cx-9/catalytic-converter-replacement-cost
 
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