Key fob not being detected

[driver42]

Hi, I am having a similar issue with my cx9. What finally resolved this issue? Did the fob need to be reprogrammed? Any insight/help is very appreciated.

 

[44below]

Hi driver42, I couldn't start my 2016 CX5 and discovered the key fob battery CR2025 fit with the cover and o-ring overtime works loose or gives intermittant terminal contact with some CR2025 battery brands. I solved this by using a CR2032 battery which is slightly thicker but otherwise identical. This gave a firm contact with the terminals and I have not had any further issues with the security recognition on start up. Hope this solves your issue.

 

[erhayes]

If you touched the fob to the start botton on the dash and the light turned red, then the fob battery is dead. Replace it and enjoy the start.

 

[driver42]

Thanks 44below/erhayes. I replaced the battery twice with a CR2032 and still no luck. I think it might need to be reprogrammed. I'll probably just take it in to the dealer. If anyone knows the right sequencing to reprogram the new (2020) fobs I'm all ears. Thanks again!

 

[ceric]

OP: "the car has not been detecting the key fob both unlocking the car and when attempting to start the car."
These are two difference sensors for detecting fob outside the door and inside the cabin to start vehicle. Even if the fob battery is dead, when you put it near the start button, the light will turn green after a couple seconds (it is RFID based) to start the engine.

So, that leaves two possibilities, IMHO.
Low main battery (12V) or BCM.
The chance of both sensors fail at the same time is rare.

My two cents.

 

[BWJ]

Just wake up the key ;-)

Works on all Mazdas.

 

[ceric]

Nice trick. Should be somewhere in the WorkShop manual. I used to have the WorkShop manual for my '08 CX9. It had lots of tricks like this.

 

[driver42]

Thanks all! Waking up the key was what did it.

 

[ceric]

Driver42,
Did you put it to sleep? Or, the fob went into hibernation by itself?

 

[yrwei52]

Just wake up the key ;-)

Works on all Mazdas.

I wonder if this function is only on new thinner Mazda key fob or also on older style key fob? It’d be nice if we can turn the unused key fob into sleep mode to save battery life.

 

[BWJ]

I wonder if this function is only on new thinner Mazda key fob or also on older style key fob? It’d be nice if we can turn the unused key fob into sleep mode to save battery life.

It works on all fob´s from 2016, says my carpusher

 

[TBD]

Doesn't work on my 2019 GTR.