2007~2015 What "senses" key in 2010 Mazda CX 9

chcastan

Member
My car 2010 CX 9 "thinks" the key is ALWAYS in the ignition. It wouldn't bother me much, but it does NOT allow the remotes to work. Occasionally, like 1 of every 10 times, when I remove the key after driving, the lock and key works as designed and the remote works (no beeping when I open the driver's door). So I thought, maybe something was getting stuck in the lock.

I read somewhere that there was a piece of metal that the key moves out of the way to tell the car if it inserted or not. Yesterday I took apart the Ignition Key Cylinder (just like this https://www.autozone.com/interior/i...ition-lock-cylinder-lc65459/343539_0_0_141469 but without the long thin metal hook, don't know why). I give it a good clean as the keys were starting to stick a bit. I removed and reassembled the pin tumblers, also strung a bit the springs to make them a bit perkier. Now it works like new, but I did not see ANYTHING that the key pushes besides the little pin tumblers. The car STILL acts as if the key is ALWAYS inserted (beeping and the remote is not responding).

I don't know how to fix the issue. The only wires getting to the ignition lock cylinder, are getting to that black attachment, which I am guessing is the FOB key transponder. May it be that, that black part is to blame? I wonder if that has some sort of metal detector in it. I figure it cannot be the transponder itself, since the car can sense when a "dumb" key is inserted. Maybe I missed something. There were a couple of plastic parts that moved and I could not figure out what they did. Again, replace a $500 dollar part for a tiny piece of plastic sounds sad (particularly for my pocket). I wonder if somebody who knows could help me here. WHAT SENSES THE KEY in the ignition? Thanks in advance.
 
Ok, finally figured out what the problem is. The key has a mechanical sensor which is NOT directly part of the Ignition Lock Cylinder, but it is attached right next to it and senses a little piece of plastic that IS part of the Ignition Lock Cylinder. The solution is actually piece of cake and here it is:

To access the *ignition key lock cylinder* and also the key sensor push switch, you need to unlock and pull the driving wheel towards the front (to give yourself some space to work). You can easily pop the top part covering the area of interest. Then remove 3 star screes from underneath the wheel and put it aside. Now you should have a good view of your working area, like so:

https://photos.google.com/share/AF1...?key=WV9XTTBaUXRPUl9FY0tyZERWM0x0OHdXT3lzTmJ3

There are two things connected, one is the transponder (white connector with some red plastic, in the image it is unplugged), and a black connector with two wires. That IS the KEY SENSOR.

https://photos.google.com/share/AF1...?key=WV9XTTBaUXRPUl9FY0tyZERWM0x0OHdXT3lzTmJ3

The not so elegant, but simplest solution is to unplug that black connector. The car will not beep if you forget the key in the ignition, but the car still starts normally and your remotes should work now. END of story [YOU CAN STOP HERE]. If you want to learn more details continue reading. The unplugging looks like this:

https://photos.google.com/share/AF1...?key=WV9XTTBaUXRPUl9FY0tyZERWM0x0OHdXT3lzTmJ3

https://photos.google.com/share/AF1...?key=WV9XTTBaUXRPUl9FY0tyZERWM0x0OHdXT3lzTmJ3

That white little plug IS the key sensor itself. When everything is assembled it matches inside the lock with the white little plastic part that is part of the key lock cylinder and in my case seems to be a bit worn, like so:

https://photos.google.com/share/AF1...?key=WV9XTTBaUXRPUl9FY0tyZERWM0x0OHdXT3lzTmJ3


That white plastic part in turn matches with the GREEN plastic part in the cylinder itself.

https://photos.google.com/share/AF1...?key=WV9XTTBaUXRPUl9FY0tyZERWM0x0OHdXT3lzTmJ3

When the key is inserted, like in the image it pushes the green part, which in turn pushes the white part of the cylinder, which pushes out the white little plug which is the key sensor and is wired in the second image.
In the lock, it looks like of like this:

https://photos.google.com/share/AF1...?key=WV9XTTBaUXRPUl9FY0tyZERWM0x0OHdXT3lzTmJ3

To recap. If your car always *thinks* the key is inserted maybe because the green part in the cylinder is stuck (dirt), or the white part in the cylinder is stuck, or the little "plug switch" is bad. Replacing the *Key Lock Cylinder* which is a $500 dollar part might or might NOT solve the problem depending if the problem is a cylinder plastic part or it is the switch. If you simply unplug the switch, you won*t get alarms if you leave the key in the ignition, but that solve the problem. I never care for the alarm for forgetting the key anyway. Your call. I hope this help somebody out there. I wish I had found this explanation last week.
 

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