Key fob acting strange

[giannhs4]

Hello guys i have a toyota avesis 99 and recently my wireless key fob is not working properly.When i try to unlock or lock it with the wireless key i doesnt respond most of the times,but sometime it unlocks it normaly.I have noticed that when i touch the key fob in the rear  left back of the car it works everytime.I have tried to reprogrammed (according to the user manual)but nothing .Has anyone any ideas on what could it be .Thank you i advance.(And sorry for my bad english hope you understand it😂)

[Mooly]

Hard to say tbh. It could be one of countless things but I'll just mention something that happened a few years ago on our old Corolla. It would lock/unlock OK at home but would not lock consistently once driven for a mile or so. You had to keep trying many times and opening closing the door. It didn't make sense what was going on but I gave the locks (the door latch itself) a good quirt with WD40 and also into the lock barrel on the drivers side. That was 4 years ago and it has been perfect ever since. Go figure 🙂  

[giannhs4]

Same thing with my car when try for about 10 times it works.i suspect the central key circuit of the car is faulty ore has some corositon on the connectors or smth but i am not sure where it is located even though i looked in the cars manual.

 

[Mooly]

It could be many things. All you can do is eliminate the easiest first. 

Are you sure the key itself is transmitting OK? Lithium coin batteries can do strange things when asked to supply initial current and then as you keep trying they start to work better... it is a known and documented issue with such cells.

[flash22]

Change the fob Battery iirc the remote receiver is under the parcel shelf behind the rear seat (in the right 1/4 of the estate) Edit. that's the t270 doh!

T22 - its in the front right footwell

T25 - It's buried behind the glove box

[Konrad C]

Mk1 Avensis keys can be re synced. I had a similar problem, then found out via this forum and in the owners manual. This fixed the issue.
 

It only works on T22 Mk1 Avensis, as far as I know.

[Konrad C]

Here is the page from the handbook regarding the Mk1 remote central locking -

 

I scanned it many years ago, before I sold the car. The resync function is the part you need to try. 

[giannhs4]

On 5/30/2021 at 9:39 PM, Mooly said:

It could be many things. All you can do is eliminate the easiest first. 

Are you sure the key itself is transmitting OK? Lithium coin batteries can do strange things when asked to supply initial current and then as you keep trying they start to work better... it is a known and documented issue with such cells.

i changed the cells on both of my keys.i havent seen any diffence.i suppose its another issue.i dont konw

 

[giannhs4]

On 5/31/2021 at 12:03 PM, Konrad C said:

Here is the page from the handbook regarding the Mk1 remote central locking -

 

I scanned it many years ago, before I sold the car. The resync function is the part you need to try. 

i tried it but nothing🤷‍♂️

 

[Mooly]

On 5/30/2021 at 10:08 AM, giannhs4 said:

I have noticed that when i touch the key fob in the rear  left back of the car it works everytime.

Can we just go back to this that you said in the first post.

Are you saying that if you allow the key to touch the bodywork then it locks and unlocks every single time and that if you then move the key away from the car it does not work. You touch or alter nothing else.

Is what you said here something that is repeatable time after time?

If it is then I think you have to be looking at a problem with the radio receiver part of the central locking and it being low sensitivity for some reason.

 

[giannhs4]

On 6/1/2021 at 9:54 PM, Mooly said:

Can we just go back to this that you said in the first post.

Are you saying that if you allow the key to touch the bodywork then it locks and unlocks every single time and that if you then move the key away from the car it does not work. You touch or alter nothing else.

Is what you said here something that is repeatable time after time?

If it is then I think you have to be looking at a problem with the radio receiver part of the central locking and it being low sensitivity for some reason.

 

yes exactly.but  i cant really find the place where the receiver is located

[Mooly]

I don't know either but I would guess it would be within the car rather than under the bonnet because otherwise all the metal would shield it. So perhaps integrated within some control unit within the car such as perhaps the immobiliser. It may be a just a short wire that seems to go nowhere or it could even conceivably use an existing wiring harness as an antenna.

More thoughts... have you got any kind of metallic tinting on the windows that could prevent a radio signal entering the cabin or any other modifications anywhere?

 

 

[flash22]

i will see if i can find the routing diagrams

LHD W4 looks to be above the brake pedal in the vicinity of the steering column

t22 lhd dash route.pdf

 

 

[giannhs4]

On 6/5/2021 at 10:02 PM, Mooly said:

I don't know either but I would guess it would be within the car rather than under the bonnet because otherwise all the metal would shield it. So perhaps integrated within some control unit within the car such as perhaps the immobiliser. It may be a just a short wire that seems to go nowhere or it could even conceivably use an existing wiring harness as an antenna.

More thoughts... have you got any kind of metallic tinting on the windows that could prevent a radio signal entering the cabin or any other modifications anywhere?

 

 

i have installed a backup camera by myself but nothing else.btw the problem existed before i install the backup camera