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Anomalous Behaviour Of Electronic Key


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Toyota Key Instability Problem

Here is another problem that the Toyota company has ignored. A rather strange one.

The Corolla Verso and the Prius models both use the same kind of electronic key which has two separate functions : to start the engine and to open and close the door locks.

My Verso is four years old and almost from the beginning the keys malfunctioned in a strange and undesirable way. I reported this every time I took the car for service but although the dealer’s service was impeccable in every other respect no notice was taken of the anomalous behaviour. They tell me no one else reports the same problem and, smiling, politely imply I am mistaken in my observations.

(Or that they don’t care).

I have exchanged lengthy correspondence with Toyota at local, national (Spain), European and headquarters’ levels - up to and including the president’s office. They are all unfailingly polite but finally unwilling to recognise the problem.

 Which is that every so often the key spontaneously sends a signal to either unlock or lock the doors.. i.e. without the buttons having been pushed or even touched. In many cases it was certain that there could not have been any accidental button pushing while the key was in my pocket. Touching or stroking the plastic body of the key (away from the buttons) may sometimes have been associated with this effect which makes me suspect possibly an electrostatic influence on the internal circuit.

It is not possible to deliberately provoke the anomalous behaviour nor to predict when it will occur and it is very irregular : sometimes happening several times in a day, sometimes with a long interval between events. No apparent correlation with ambient temperature or other conditions.

 There is an obvious security implication : the effect often happens when walking away after parking and locking the doors. Masked by traffic noise a spontaneous reopening may not be noticed, leaving the vehicle open, at least for a period until automatic reclosure might occur (if it occurs).

 The key I am currently using shows the effect very strongly and it is obviously very unstable. The most recent instances of unprovoked signalling have occurred when walking or standing a few metres from the vehicle which had been parked unused for several hours ; the key being loose and unencumbered in my pocket. In one case in fact, having just been removed from my pocket and being held loosely in my open hand, my fingers nowhere near the buttons, the key sent a signal all by itself to open the doors. On this occasion the event was witnessed by my wife (who had previously been a bit sceptical).

 The first key that showed this problem many times eventually gave up the ghost and the door control stopped working altogether. (Engine start is not affected). It was examined at the dealer’s who offered no explanation, merely confirming the key was kaput.

If the failure is part of the general problem and if static is the cause, the internal circuit may have been destroyed by a static charge in a similar fashion to when sensitive computer circuit boards are not handled with precautions. Obviously, in the case of a key no such precautions by the user are relevant.

Another possible cause is a loose internal contact.

 This failure caused two more disagreeable surprises :-

A) Toyota refused to recognise the failure as being covered by the (extended) guarantee.

B) The price for a new key would be more than €170 ! ($246 ; £154 )

This reflects a rather dastardly marketing policy common to many manufacturers. It must cause great irritation to customers while having minimal effect on profits since the sale of spare keys can hardly be big business within the general scheme of things.

 It is even more irritating : as an electronics engineer I’d estimate that the manufacturing cost of the Verso/Prius type of key is hardly more than a few Euros or dollars, whereas here, for less than €120, you can buy a good 22” flat screen computer monitor – which in every way is infinitely more complex.

Hopefully a bit of public attention may lead to some light being shone on this matter.

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My Prius does this!

BUT.... It's when I'm washing it and the key fob is in the pocket of my jeans and I'm bending down to do the sills, the crease of the pocket as I'm bending down pushes the button to lock or unlock the car... Not a problem IMO as I'm there and the car is always locked when I leave it.

Rhe same 'toggle' happens while I'm washing either of the front doors, the key fob is close to the door, so is my hand, the door locks/unlocks...

I put it down to the strong signal sent out by the fob.

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Maybe it's just a faulty fob, these things do go wrong. The only way to check it is to replace it. It may be a few quid but it would save a lot of time worrying about it and the inconvenience of your car being open when you dont want it to be

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Obviously there are a few things you have already tried and maybe you have already been through these suggestions but here goes:

The car is supplied with 2 keys, does the same thing happen with either?

Would the dealer let you have another car of the same spec for a 2 week trial period to see if the same thing happens?

If the same thing happens no matter what key is used it would suggest the fault lies within the car electronics not the key electronics.

If the same thing happens with a completely different car it would suggest it is something to do with environmental factors around the key/car.

Either way just applying the tests above might help to narrow down the problem.

As a side note on the Verso if you accidentally unlock the car and no doors are opened within a set time it automatically re-locks itself.

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