Key fob dead...battery dead...bcm replacement? Help please.

10 July 2020 05:28
2014 Cx 9. My key fobs stopped working. Then months later i have dead battery. Could not charge battery with out theft deterent alarm going off. Had it towed. They replaced dead battery Key fobs not working. Ordered outrageously expensive $ 358.00 new fob and still not working. Mechanic says bcm not working.

Mechanic says if i dont want theft deterrent or use key fobs i can take it home without replacing bcm. New bcm $958. Will it damage anything else in my car if i just bring it home without replacing bcm and forget using key fobs? Help please…
2009 Mazda CX-9 GT
Yes, you can use the key only and not have any theft deterrent features. I'd have to check when I get home, but I thought there was a theft deterrent module, rather than the BCM doing this task.
2009 Mazda CX-9 GT
Confirmed. There is a "keyless control module", #13 in the diagram. Based on what you have told us, I would look at it before the BCM.


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2011 CX-9 GT AWD
week of Xmass 2019, i had similar issue. I was planning to run somewhere and started the vehicle. about 30 sec, car shut off. KEY light was red. i couldnt use the metal key because I have 1 key and keep metal key on the chain of my other car. long story short. i checked fusebox. I forgot the fuse number. it was 10amp calls speedometer. it was blown. i replaced and started ... samething, blown. I went to dealer, they said speedometer needs to replace. $1200 + 7 days progress (mileage transfer...bla bla).

I bought new fuses at napa. removed entire fuses in the glove box and tried to find which feature gives issue and blows the fuse. i install 1 fuse and start the vehicle.shut off another one. when i complete the entire fuses, car worked fine. What was the issue, I was driving night time before a day and speedometer was on night drive mode. i turned day drive mode on then tried the fuses. everything fixed for $10 (2 boxes of fuse).

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