2005 Corolla

[digcot65]

Hello Ive been loaned a  2005 Corolla by a friend,as my Mazda 2 has an expensive fault appear Im very impressed with the Corolla ,much better drive than the Mazda Ive noticed the remote buttons on the key fob dont operate the doors Ive fitted  a new Battery but still dead.Is there a procedure to rematch the key buttons to the car Len

[Cyker]

Do you only have the one key? If not, try the other first.

Also, pop the module out and inspect it - The fobs from that era are known to have slightly fragile buttons, and it's not uncommon for them to get sheared off the circuit board, or at least fracture the solder joint.

Does the light blink on the remote when you press the buttons?

TBH the easiest thing would be to get a dealer to reprogram it, but I have a programming procedure for a Mk1 Yaris, and from memory the procedure is the same for the Corolla as they're both from the same time period, so worth a go:

Toyota Yaris 1999-2006 remote programming instructions

1. Open the driver’s door.
2. Insert the pre-programmed working key into the ignition lock then remove it. Don’t turn the ignition on.
3. Within 40 seconds: Close and open the driver’s door twice, then
4. Insert the new key into the ignition then remove it. Don’t turn the ignition on.

5. Within 40 seconds: Close and open the driver’s door twice, then
6. Close the driver’s door, then

7. Insert the new key into the ignition and turn the ignition on then off (Once to ADD or Twice to Erase All and Add), then
8. Remove the new key, then
9. The central locking should now lock then unlock (Once or Twice).
10. Press the lock and unlock on the remote at the same time for 1.5 seconds
11. Within 3 seconds, press the lock button on the remote for 1 second.
12. The central locking should lock and unlock once.
13. If the central locking locks then unlock twice then the sequence has not been successful. Try again.
14. Open the driver’s door to complete the sequence.
 

Some hints: Read through it a few times before you attempt this and get a feel for the sequence, as you have to do it smoothly and quickly. Expect to have to attempt it a few times before you get it to work (I think I tried nearly a dozen times the first time I tried this, before I got it to work, because I was trying to read it and do it at the same time!).

It's really easy to mix up the order of putting the key in and fiddling with the door etc. 

The only caveat is I've only tried this for coding a new key, not refreshing the code on a single key. I assume you can use the same procedure, but use the same key for all the steps instead of swapping between an existing key and a new key, but I can't say for sure.

[digcot65]

I had a new Battery fitted into the key,but no light comes up Len

[Mooly]

If the light on the key doesn't work then its possible the Battery contacts are not making a good connection. You need to carefully check and if necessary gently retention them so they contact the Battery correctly. Make sure they are clean and make sure the Battery really is OK and fitted the correct way up.

[Cyker]

That's a good point, and also the contacts are known to get a layer of corrosion sometimes, so giving them a bit of a scrape may help...?

Also, make sure there isn't a layer of plastic stuck to the coin cell - I seem to recall one forum member falling for that some years ago  

Hopefully that's all it is, and not the buttons being damaged... 

[digcot65]

I had a new Battery fitted into the key,but no light comes up .I took the key,back to the shop that fitted it . They checked and found the key was transmitting a signal So Ill have to see if I can match it up to the car Len

 

[Mooly]

Its a bit odd the LED isn't illuminating tbh. Assuming they used a proper bit of kit to check it was transmitting then you just have to take that at face value. 

It doesn't sound hopeful to me though.

 

[Cyker]

I'm wondering if the signal they were testing was the immobilizer or the remote locks...

 

[Mooly]

I don't know. The key in the picture is the same as for our ancient 2003 Corolla.

Checking the output properly really needs proper kit like a spectrum analyser to check it is at least transmitting on the correct frequency. That's highly specialised.

My instincts say if the LED is not lighting then there is a basic problem because the LED as far as I remember is actually pulsed with the data needed to alter the carrier, in other words if you move the key and its lit LED quickly across your field of vision you can 'see' the data, the LED is pulsed and not just constantly lit.

I think the key is faulty... well it must be in part for the LED not to light. Maybe it actually is transmitting but there is no data present.

It would be worth cracking the key open (easy with a thin coin) and separating the internal plastic clamshell to expose the innards and make sure that it show zero signs of moisture damage which would look like white milky deposits on the circuit board and components.  

Random picture but it should look super clean like this on both sides:

Water damage looks like this:

[digcot65]

Back again, as I said I took the key to have a new Battery fitted When I found it still didn`t work  i took it back to be tested ,they said it was OK .However to be on the safe side I fitted a new Battery myself,but still no light when the buttons are pressed and doors still  don1t open .

What next , neither key opens the doors neither key lights up when buttons are pressed .A friend has loaned me this car,while I look for another one ,he said that the last time he tried it the central locking worked But it was some time ago as the casnt been used,since his wife stopped driving  .Len

[Mooly]

Given the LED does not light is conclusive proof there is a problem with either the key itself (the circuit board) or the Battery or its contacts. The LED should light when you press the buttons. 

Have you measured the Battery voltage of the key and also tried to see if this voltage falls slightly when you press a button as a fall indicates it is at least drawing some current. A new Battery should be around 3.2 volts off load at a guess and will drop by perhaps 0.1 or 0.2 volts under load.

Don't look to hard for a fault, something fundamental is wrong for both keys not to light up. If the keys are not physically damaged and have not suffered water damage then it is almost certainly just a battery/contact issue.  

[digcot65]

Thanks Ive measured the new Battery voltage and its fine However I`ll try in situ ,when its being used and see if it drops. If that`s the problem ,the I suppose I can get a replacement circuit board,for the key Can I then program the new board to the car soI have central locking Len

[digcot65]

Ive just found a firm on line "ALI EXPRESS "advertising a new  blank key,with the circuit board in it  . If  I bought  this ,how to program it to match the cars central locking .Im in an awkward position,a friend a friend has loaned me his wife`s car as she no longer wants to drive .He said I can keep it for a year if I want and he has given me the V5 to put the car in my name .But I think for sentimental reasons,he or his wife does`nt want to sell it The car has sat on their drive for a year I checked it over and took it for an MOT and it passed.I am going to  have to tackle the subject and ask if he would sell it ,but its awkward Len

[digcot65]

Sorry forgot,this is the Corolla Im talking about .Its older ,than I would have gone for but its condition is so very good .I also think my friends would be happier to still see it I have feeling it was a car their son bought for them,but sadly he suddenly died a year ago Len

[Mooly]

On 8/27/2023 at 9:29 AM, digcot65 said:

If that`s the problem ,the I suppose I can get a replacement circuit board,for the key Can I then program the new board to the car soI have central locking Len

I don't know what is available as replacements tbh nor do I know how you would program a 3rd party replacement key.

When people talk of reprogramming a key they usually mean getting the transponder chip for the immobiliser to work. That chip is physically moulded into the key and is a different thing and not part of the removable module with the Battery and buttons. There will be a way to program the central locking function but I don't know what that is.    

 

[digcot65]

I was thinking,of taking the board out of the key Id bought and fitting it into  my original key The hopefully matching it up so remote  works Len

[beeblebrox]

BOTH keys do not light up. Some sort of transmission proven from keys.
Only explanation I can think off is.
Pressing key button transmits code to car.
Car replies to Key to light LED (all OK).
If key is not coded correct it won't invoke a OK sigal from car.

Is the key LED supposed to light when pressed well away from car?

[APS]

1 hour ago, beeblebrox said:

Is the key LED supposed to light when pressed well away from car?

Yes. It does not indicate successful comms with the car. 

In fact, I've had a few of these keys where the LED has died and the key still works fine.

[beeblebrox]

Well there goes my theory.😄

[Mooly]

16 hours ago, beeblebrox said:

Is the key LED supposed to light when pressed well away from car?

Yes, the LED lights when no car is present. There is no two way communication from the central locking, its just a simple one way transmission.

On 8/28/2023 at 4:07 PM, digcot65 said:

I was thinking,of taking the board out of the key Id bought and fitting it into  my original key The hopefully matching it up so remote  works Len

The little capsule containing the Battery and board is self contained and works when not fitted to a key. You do not need a key for that capsule to work.