Remote Key

[oriana]

Hi

i have a problem with my remote key on my 4.2 it sometimes works and sometimes doesn't ,i have been through all the old posts and have changed the batteries and re sync but no change.

It works in my garage and sometimes on the drive and rarely out and about.

Any ideas before i take the plunge and take it to Mr T.

Many thanks in advance

[anchorman]

Hi

i have a problem with my remote key on my 4.2 it sometimes works and sometimes doesn't ,i have been through all the old posts and have changed the batteries and re sync but no change.

It works in my garage and sometimes on the drive and rarely out and about.

Any ideas before i take the plunge and take it to Mr T.

Many thanks in advance

When you changed the batteries did you hold them by the edges? If you hold them across the flats you can discharge them in seconds.

[oriana]

Hi

i have a problem with my remote key on my 4.2 it sometimes works and sometimes doesn't ,i have been through all the old posts and have changed the batteries and re sync but no change.

It works in my garage and sometimes on the drive and rarely out and about.

Any ideas before i take the plunge and take it to Mr T.

Many thanks in advance

When you changed the batteries did you hold them by the edges? If you hold them across the flats you can discharge them in seconds.

Not sure the man in the shop fitted them in the old 3v batt was reading 2.8v i only changed the batteries on 1 remote as the second one had never been used but is 5 years old,but why does it sometimes work and sometimes not.

[anchorman]

Hi

i have a problem with my remote key on my 4.2 it sometimes works and sometimes doesn't ,i have been through all the old posts and have changed the batteries and re sync but no change.

It works in my garage and sometimes on the drive and rarely out and about.

Any ideas before i take the plunge and take it to Mr T.

Many thanks in advance

When you changed the batteries did you hold them by the edges? If you hold them across the flats you can discharge them in seconds.

Not sure the man in the shop fitted them in the old 3v batt was reading 2.8v i only changed the batteries on 1 remote as the second one had never been used but is 5 years old,but why does it sometimes work and sometimes not.

The short answer is - I don't know!

I can only tell you that when the batteries are low sometimes they work and others not. I guess it depends on temperature, what angle and distance you are from the car and whether the signal is corrupted by other electrical fields. For what it costs I would try some more but be sure to wipe the protective residue off with some kitchen roll and hold them across the edges (tricky as they want to escape!!!)

I thought I had some photos but i can't find them. Easy enough though, just unscrew the cover and change them.

[Davrav]

I thought I had some photos but i can't find them. Easy enough though, just unscrew the cover and change them.

Are they similar to the ones in the pinned technical hints and tips for the 4.3 by any chance ?

[anchorman]

I thought I had some photos but i can't find them. Easy enough though, just unscrew the cover and change them.

Are they similar to the ones in the pinned technical hints and tips for the 4.3 by any chance ?

Similar Dave but they were the exact ones for a 4.2. I have several SD cards and can't seem to find the right ones.

[Goggy]

My 4.1 used to do the exact same thing but only when it rained !!!!!

i never did get to the bottom of it

i gave the car to my son last year and HE has NEVER had a problem with it

Twilight Zone or what????

[oriana]

wife came home from work today and said she couldn't lock it with the key at work at asda and on the drive at lunchtime ,she put the car in garage and hey prestow it locked first time not that we lock the car in the garage but she was just showing me.

By the way folks this is the wife which filled the rav up with petrol when it's a diesel and its been fine.

Just this key issue.

[oriana]

wife came home from work today and said she couldn't lock it with the key at work at asda and on the drive at lunchtime ,she put the car in garage and hey prestow it locked first time not that we lock the car in the garage but she was just showing me.

By the way folks this is the wife which filled the rav up with petrol when it's a diesel and its been fine.

Just this key issue.

Put another new Battery in today and no change it works fine in the garage but not when out and about .

Could it be to do with the recent heat,however it played up at 8 am when it wasn't that hot.

[oriana]

Can anybody tell me where the receiver for the remote key is as have changes both batteries again but still it works intermitently

but always in my garage,it must be a problem with the receiver could it be that in a confined space the signal is stronger?.

Thanks

[oriana]

Forgot to ask should the central locking work with the key from the drivers side as my doesn't ,however it does work from the internal switch.

[chatman]

Forgot to ask should the central locking work with the key from the drivers side as my doesn't ,however it does work from the internal switch.

Do you have any big power lines near you.... you know those massive buggers you always wanted to climb when little but never did because you did not want frizzy hair.......

The switch internally is connected direct to the box.. so will always work.... does the key lock the RAV fine from both door key locks....

[oriana]

no it only locks the door which you put the key in.

also no power cables arround

thanks

[chatman]

no it only locks the door which you put the key in.

also no power cables arround

thanks

Look up a good Auto Electrician... to give the car a look over... see if they cant find any faults in the wiring loom etc....

[oriana]

ok thanks but how come it always works in the garage

[chatman]

ok thanks but how come it always works in the garage

I would say being parked in the garage as this is a confined space...possible this is helping the ECU to receive the signal better... May have issues with the receiver or similar....

I'm no auto electrician.... but parked in open spaces, the receiver is not strong enough to get signal due to fault.... I could be wrong..... :unsure:

[Dippy]

I've seen posts where people's cars randomly refuse to arm/disarm by the remote, or even not start with the key.

Check if it always does this when parked in the same spot. It seemed the answer was, there was some sort of transmitter nearby which interrupted the remotes, or affected the engine starting coding.

People would push their cars 10 yards to a different spot and they'd then start with no trouble at all!

Just a suggestion.

[chatman]

People would push their cars 10 yards to a different spot and they'd then start with no trouble at all!

Just a suggestion.

PUSH...... Have you ever tried pushing a full time 4x4 RAV.... Even my wife struggled when she was needed to push mine.... :!Removed!: :!Removed!:

[shcm]

Oh well, here goes:

Transmitter Key

It all depends on the key design, i.e. what chips have been used, but I would have thought 2.8V would be more than OK. This one (non Toyota), I heavily modified a few years ago to control a car PC remotely. It gives up at about 2.5V to 2.6V, but that is due to the small micro-controller I added (small back thing bottom right) and not the rest of the key.

Yes, try not to touch the Battery, wipe it clean with a cloth if you do. Make sure it fits reasonably well/tight in its holder or cradle and/or is reasonably tight against the Battery contacts in the key and that those contacts are clean too. I know some manufacturers have had to put a good deal of effort into Battery holders in the past, to overcome problems with loose batteries.

Of course, there are a whole load of things that can go wrong with the key. For example, if the mechanics are not well designed, repeated operation can flex/crack the PCB (printed circuit board) itself and/or produce hairline cracks in some of the small components on the PCB. This can be difficult to spot without a microscope, but can lead to intermittent operation.

As an aside, ECUs very often have a "drop test" specification that they have to pass during design validation. Usually about 1 metre onto a concrete slab. It is mainly so that if the ECU gets dropped by a fitter on the car assembly track, it doesn't break. In the past, a few manufacturers also applied this spec to the remote locking key, not thinking that keys go through much more abuse in that respect, (thrown across rooms or from windows for people to catch etc).

If you know anybody with a scanner/receiver, you can do a very basic check that the key is at least transmitting every time you press the button. Usually (although not always) it will need to be tuned to around 433.92 MHz (Europe) 315MHz (US, Australia). Very often, the data rate from the key is low enough to be heard on the receiver. Try both AM and FM.

However, the fact that you are having problems with both keys, suggest the problem is with the vehicle and not the key.

Receiver

I never went looking for the receiver on the 4.2, but this suggests it is near side rear:

The first thing is to get up close to the vehicle in roughly the position of the receiver, and see whether repeated operation works OK. Just bear in mind that on some vehicles, the electric door latches are not designed for rapid repeated operation. If they are operated a lot, they tend to get hot. In the past at least, some manufacturers have implemented a "latch cool off" feature in the body controller software. After too many rapid lock/unlock operations, the latches are deliberately not operated for a while, so they have time to cool down.

If that works consistently, then there is a possibility the receiver has gone a bit deaf. High temperatures can reduce the sensitivity of the receiver (you get an increase of noise in the receiver itself while it is hot). One manufacture found under heavy solar load (lots of sun ), the locking range reduced considerably. The ambient temperature where they had mounted the receiver exceeded its temperature design spec a fair bit.

Yes, you can get interference from various sources, that can reduce the receiver sensitivity or in some cases block it completely. That is several topics in itself (in a former life I've been involved in trying to fix or improve badly designed receivers with respect to this).

Is your garage metallic? Or does it have a large metallic door? A signal bouncing around in such a structure, can, in some instances, be easier for the receiver to hear. (Operating the remote locking at long distance on some empty high speed ferry car decks can sometimes be interesting). Have you installed anything else non-standard electrical in the vehicle?

What happens if you hold the key higher (or even above your head) while pressing the button? Does it improve things? (There's some peoples old favourite of holding the key under your chin too).

Just remember, a large percentage of vehicle electrical problems are simple wiring or connector problems. It could be something as simple as a bad receiver earth, or if it has a separate antenna (usually they don't), a bad connection with that.

Very difficult to fault find these things remotely (if you'll excuse the pun), but just shout if you have more questions. Good Luck!

[Davrav]

I seem to remember something from an old Top Gear that holding the key against Clarkson's head increased the range. Perhaps you can get him round..................................... ;)

[oriana]

Graet report shcm thanks

i will try these tests out and report back ,we found out today that if you use the remote from inside the car it works everytime,jump out it may lock once or twice then nothing again.

It is a standard Toyota key with a lock and unlock button and no we have never added any other electrical device to the car,thanks again for the help i will report back.

[shcm]

we found out today that if you use the remote from inside the car it works everytime,jump out it may lock once or twice then nothing again.

Yeah, that doesn't surprise me. A receiver gone "deaf" is sounding more likely at the moment.

If you can, I'd try outside, close up to the vehicle to begin with and close the where we *think* the receiver is.

Sometimes, it can help to have the key above the "window line" too.

If it's consistent like that, try other positions close up to the vehicle.

Cheers

[anchorman]

Shcm - where have you been? Just the kind of excellent account we were missing from our electronics guru

[oriana]

ok

wife came home from work today and i was all set to try out some of shcm's tasks when she tells me it's been working fine all day about 10 lock and unlock situations.

i tied it and hey prestow it worked each time i tried, now i'm even more confused i suppose just leave it and see because tomorrow is another day.

[chatman]

ok

wife came home from work today and i was all set to try out some of shcm's tasks when she tells me it's been working fine all day about 10 lock and unlock situations.

i tied it and hey prestow it worked each time i tried, now i'm even more confused i suppose just leave it and see because tomorrow is another day.

Always the same with cars... once they know you want to fiddle with them they start behaving them self....

been working fine all day about 10 lock and unlock situations.

Is the wife a taxi driver then.... ;) ;)