Mazda 6 Forums banner

Key Fob will not start car

61K views 23 replies 12 participants last post by  Aileen 
#1 · (Edited)
I have a 2008 Mazda 6. I have two key fobs. One I use regularly with no issues. The other is on my wife's keys. She tried to start the car the other day and came in and told me the battery was dead. This is impossible since I had recently replaced it and drove the car myself only hours before.

I took my key fob and had no issue with starting the car. I later tried her key fob to only find it not to start the car. It unlocked doors with no issue but when I tried to turn the key over to start the car, all I got was a humming noise and a click but no start.


QUESTION:

Do I need to replace the key fob?
Do I need to replace the battery in the key fob? (DONE as of July 6)
Do I need to reset the key fob? (DONE as of July 8)

Any answers are certainly appreciated and happy 4th to all!


Thanks!
:bowdown::bowdown::bowdown:
 
#3 · (Edited)
No luck with battery change




Thanks for the response.

The car battery was installed correctly and the car works fine. No alternator problems or any other electrical issues.

Decided to change the battery for the key fob. Unfortunately, the change of battery (CR 1620) did not do the trick. Can still open the trunk, unlock the doors, etc. As soon as one turns the key, you get a "humming" sound and no start. :eek: :eek:

Thus I ask for any other helpful insights. As mentioned, the other key fob works fine.

Thanks for looking and I hope that I am not the only one that has experienced this. I find it very odd that one key fob works fine and the other is doing as described above.
 
#4 ·
take it to the dealer. they have certified mechanics for a reason, right?
 
#6 ·
Key fob still not working....



Thanks but I was hoping to avoid the dealer for a key fob issue. This doesn't really make a ton of sense. Apparently, I am the only person with a Mazda that this has happened to (which I find hard to believe).

:D:D
 
#8 ·
Not the remotes battery, the cars battery

If the key lost programming, the car wouldnt try to start at all, no clicks, no nothing. Just a flashing security light in the instrument cluster.

I still say its the cars battery.
 
#9 ·
Sorry but I disagree............




Sorry but the car battery is fine and was just changed. As I stated, both remotes came with the car when I purchased brand new from the dealer. My remote is fine even after the battery change. The other key fob was rarely used but did work and then suddenly stopped working. It would not start the car and would only give a humming sound when one turned the key.

The technician said that the instrument cluster did show a flashing security light. This is what was so puzzling since it should have been easily reprogrammed. The beauty of the internet is that some other poor person with the same unusual problem will hopefully not waste as much time as I did and move onward at a lower cost than buying an entire new key fob and wasting so much money at the dealer.

Thanks for the follow up but I disagree with your assessment.


:D :D :D :D
 
#10 ·
It could just be one of those mysteries where it just stops working for no reason... like reverse lights... Byakuya... lol
 
#11 · (Edited)
Ahhh. So u do have a security light flashing. That says it all. Flashing light = immobilizer issue

However you also did state you heard a clicking when u try to turn the car over. Clicking with out the engine turning is a sign of a dead battery, hence the suggestion.

If the engine keeps turning over, never fires up, And there's a flashing security light, the ECM is not recognizing a valid key therefor not allowing the car to fire up.


Oh yeah, let me correct myself. My previous reply was wrong. Most Fords and Mazdas will turn the engine with an unrecognized key. It just won't fire up and give
U a flashing security light. I have plenty of these expierences when I have to install remote start systems.

that humming noise is the fuel pump priming up.

And it is possible to bump a programmed key out of memory when too many keys are in close proximity and cycling the ignition.


Glad u got it fixed tho
 
  • Like
Reactions: kdrew
#14 ·


Thanks. This thread will enlighten some poor person with the same issue. Perhaps I need to review prior posts since it made a click not a clicking sound. The simple fact remains- one key fob worked and one did not. Both were factory issued with the car and one was used all the time, the other was not. Somehow, the chip got deprogrammed and was unable to be reprogrammed.

Like you said, I'm glad I got it fixed. Thanks again.!!

:) :) :)
 
#13 ·
LOL
 
#15 ·
Although this is an old thread...I am experiencing the same issue. I am posting to see if anyone ever came up with additional solutions in the last year. I have one working and one non working key. Both will unlock the doors but only one will start the car. I own a 2012 6i
 
#16 · (Edited)
Clearly the chip lost it's ability to start the car. The click causing all the controvicy is an electrical noise that sounds like the starter motor click that happens when the battery is too dead to turn over the starter. Well the immobilizer works the same way and the click definitely does happen when the key unlocks the ignition, but the chip fails to be read, or is read but not recognized as the correct chip. Incidentally the chip is located in the plastic housing of the key part of the controller. It's a small plastic block that looks like a part of the plastic casing, but on closer examination it can be seen as a slightly different color. If you need to replace the housing, bear in mind that the correct chip & key combination must be together to start the car. If the chip is not functioning & the warning light on the dashboard confirms this state then go to a key cutter & have them code a new chip from your spare key. The Mazda dealers will charge a fortune to do this so avoid them if at all possible.
 

Attachments

#17 ·
Bumping this for future reference.

I just swapped out fobs after my original had the key ring part break and you are right! There is a chip in the switchblade part of the key that I hadn't transferred over. Car started right up afterwards.

In case it helps anyone, I bought a shell from China to save $$ and it was missing a cutout for the panic button and the tolerances were wack as well. It served its purpose, however
 
#18 ·
For this issue it is the key. The chip pebble inside the key could have gone bad for some reason. No one knows why or how they go bad but if you have one that will start the car and the other will not it's definitely in the chip or pebble inside the key not sending the correct info to the cars ECM. Only way to fix this is to get another key. Changing the battery doesn't do anything that battery is only for the keyless entry in the fob and has nothing to do with the immobilizer pebble.
 
#21 ·
I have managed to sort my Keyless ignition issue out at last, and thought I would post it as you wont believe it!

The same as everyone else I had 1 fob worked fine opened the car doors etc and started the car. The other fob stopped working so I changed the battery, fob started working to a point, opened the doors unlocked the boot but wouldn't start the car. What i found was 2 things, 1st is that certain battery types don't work in the fob, I am told Duracell and energizers don't work. 2nd it is possible to put the battery in upside down, the fob works on opening the doors and boot etc but the proximity sensor doesn't. So if you have this issue check the battery is up the correct way. Fortunately for me I took my fob to a local lock specialist and they charged £5 to sort it could have gone to dealer and cost my £95.
Hope that helps someone.
 
#22 ·
I’m having the same problem 2005 Mazda 6 will start 100 times then I can get in it won’t starry then I can go back half hour later and will go. Then might drive once then won’t start then might have to wait a couple of hours then it will go again. It is so unreliable. It has a new key from a locksmith, has the original key with new battery and a new battery. Immobiliser light continually flashes when I try to start. Has anyone successfully fixedb this problem? Has been to Mazda dealer it started every time they tried even though it had to go a day late because my mechanic who was going to take to Mazda couldn’t get it to go.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top