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Replaced Key Fob/Moved Electronics and Smart Chip - Now it won't Start

Hello everyone…

I bought a blank shell for my car key and moved the keypad over. I dug out the little square black chip, moved that over too. I snapped the new key together, tested the keypad (it’s alive!) and took the old metal key (my new one hasn’t been cut yet) along with the new components into my car. I try turning the engine on, and it’ll crank briefly, then give up. Conversely, when I bring my existing, working car key out, it fires up just fine.

Is there a trick to this? I found a video that said “make sure you have the chip in ‘the right way’” (though they neglected to say what is right, so I dug it out and flipped it over for good measure - no difference.

The smart chip can’t possibly know that the key it’s attached to isn’t cut yet, can it? I just don’t want to run out and spend my time getting the new key cut (the $2 cutting fey is negligible) if that isn’t going to solve my problem.

Any ideas?


the most simple thing would be to spend that $2 and have the key properly cut

in absence of that, you have to hold your “new key” with transponder in it in a very short distance of the “old key” not having transponder when doing the experiment with cranking or it will not read it. having it on the dash or in your anotehr hand will not do

seriously, just spend that $2 and be done, it is no magic in the key other than black transponder chip, which you seem to identified and known how to move to another key.

Yup, the anti theft/transponder allows fuel delivery (and maybe spark too). You can crank it until the battery runs dead but it won’t start unless it sees a programmed transponder. It needs right against the steering column, right where the key is :stuck_out_tongue:

I’m not familiar with changing over the components from one key to another. I’m sure there is some risk of damage.

Sorry to piggy back on your post, but I’m trying to add a new transponder key to my car (09 Corolla) but can’t get it into program mode.
I’ve tried the gas 5x brake 6x method, and the inserting and withdrawing master key 5x. Still nothing. Toyota wants $75 to program a key that I purchased and had cut.
I’ve done plenty of things to my car (installed keyless system) so I’m pretty sure that if I could just get the car into program mode I would be able to it myself.

Go to a locksmith. They’re generally cheaper than the dealer, and can do the same work. It won’t be free, though.

For what it’s worth… I’ve grown to loathe chip keys/fobs. Give me a good old metal key any day.