RAV4 key lost communication with alarm/central locking

[GRB]

Hi all, interloper from the IQ section😀. Some elderly neighbours of mine have an 04 plate Rav 4 that is the wife's pride and joy ( it is low mileage and as new!). However yesterday they decide to change Battery in both the keys. Now neither key will operate the central locking or disarm the alarm. You can open the door by using key and start the engine but the alarm keeps going. I have tried removing Battery from keys and pressing the buttons and putting back together but no difference. Disconnecting Battery to reset doesn't help as alarm continually sounds due to the self contained back up power. Any one else had this ? It is the TVSS system

thanks

Geoff

[alan333]

First thoughts... are the batteries good, the correct ones, and fitted the correct way round?

[GRB]

Yes, new batteries correctly fitted. The LED on the key fob flashes when you press either lock or unlock. Just seems to have lost communication. Not sure why when you open car with alarm going you can start engine do not affecting the imobilisation part of system 😏

[Heidfirst]

4 hours ago, GRB said:

Not sure why when you open car with alarm going you can start engine do not affecting the imobilisation part of system 😏

Afaik the fob has a physical transponder chip in it & it is the proximity of that that the immobiliser checks for rather than alarm state i.e. the alarm & the immobiliser  actually operate as separate systems.

iirc ther are various TVSS systems but techdoc.eu may have info that can help you re-synch.

 

[GRB]

Hi, thanks have tried but as alarm is sounding doesn't seem to allow the process to work. Will have to see if I can find fuse to disable alarm and see if that works then

[IanML]

I think you need to perform the procedure below, to get the remote entry subsystem to obey the key.  Note that the master key is required.  I have done this procedure for a new second key, and it worked.  This is copied from an old post by Will E Reckit .

I'm not sure, but perhaps Techstream could be used to silence the alarm?

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Posted January 14, 2014

Here are the programming methods that worked for my 2004 XT4. Standard Immobiliser and TVSS4-D alarm system fitted.
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REMOTE/CENTRAL LOCKING Procedure:


1. Start: Driver's door open and unlocked. Key not inserted in the ignition.
2. Insert programmed master key in ignition and then remove it, without turning it.
3. Do the following with the driver's door: shut, open, shut, open, all within 40 secs.
4. Insert key in ignition and then remove it, without turning it.
5. Repeat step 3.
6. Close driver's door.
7. Insert key in ignition
8. Turn key from Lock to On and back to Lock with a 1 second interval. The number of times you do this will select the desired programming mode: Once for ADD key, twice for REWRITE all keys, 3 times for CONFIRMATION, 5 times for PROHIBITION.
9. Remove key from ignition.
10. As verification of mode selection (except in Confirmation mode), the electric door locks will lock and unlock a number of times corresponding to the mode chosen in step 8.
(If Confirmation mode is selected, the doors will lock/unlock a number of times corresponding to the number of remote controls programmed into the system.)
11. For ADD and REWRITE modes: within 25 seconds after the locks have confirmed the selected mode:
(11a) Hold down the LOCK button on the new remote control whilst at the same time pressing UNLOCK 5 times. (11b) Release and press LOCK once. (11c) if the procedure has been performed correctly, the door locks will go from lock to unlock. If not, start from 1 again.
(11d) To enter additional remotes, repeat from step (11a).
12. Open driver's door to complete the procedure.

Quite a tedious procedure but I reckon the best way is to read and learn the process so you can complete all actions within a matter of a few seconds - any delay will 'time-out' the procedure.

[daveh_rav4]

Blimey, I thought this was an April the 1st joke; but I think your serious!  I was losing the will to live reading this LOL

[GRB]

Ian, thanks assume techstream is a dealer type software tool to code the vehicle via obd port ?

Dave , yes afraid it is serious I think it may well end up at dealer or auto electrician to resolve if we can't get system to unlock and turn off security to allow us to reprogram keys

Thanks for responding guys👍

[IanML]

I bought Techstream on eBay - e.g. link.

All you need is a laptop - easy to install.  I needed it to program the immobiliser for a new key - that worked too.

[IanML]

10 hours ago, daveh_rav4 said:

Blimey, I thought this was an April the 1st joke; but I think your serious!  I was losing the will to live reading this LOL

Yes, it does work.  Known as the hokey-cokey - can't think why 

[IanML]

Geoffrey, I think I have the answer - call it the junior hokey-cokey:

1. Put key in ignition and turn to RUN

2 Turn key from RUN to OFF five times

3 Turn to START and start the engine

Alarm will be disabled.

 

Let us know if it works - I haven't tried it to avoid annoying the neighbours.

[GRB]

Ian, hi I'm afraid not, car starts but the alarm still carries on untill it's pre determined time

thanks for suggestions 👍

[IanML]

Try these, one may work:

Put the key in the driver's door and turn it twice to the right, then twice to the left. Then insert your key into the ignition and start the car.

 

Turn the key into the unlock position and hold it for two seconds before opening the door.

[IanML]

Just a thought - the first one above may apply to a LHD car, so also try twice to the left, then twice to the right.

[GRB]

Ian, I'm afraid still no joy . Think I will leave lights on and see if can completely flatten Battery and hope it allows system to reboot  when fitting recharged Battery

thanks again

geoff

[IanML]

Not sure how that will help, as I expect the lights can't discharge the separate alarm Battery (it will have a diode in the line to prevent that).

I must admit to some concern, as it could happen to me if my keyfob were to develop a defect.  There must be a way of disarming the alarm with the key - it is inconceivable that they forgot to include that function.

I have found another post, which alleges that the key should be put in the ignition and turned to RUN (without starting, I infer) and that after 30 seconds, the alarm will be disarmed.  It does not mention whether the driver's door should be open or shut, so I would try both.

[GRB]

Ian, thanks tried first thing today with no difference, alarm sounding start engine and it continued😱. Left for about 3 hours then got other key and all working ok😳

Tried other key and it to is fine 😳 Not sure what's changed but all back to normal, maybe that owner had booked in to local agent for them to check was enough to make it start working again.

must be an issue but it's finding it hope it's sorted but will let you know if it plays up again

once again many thanks for all your input it has been very helpful👍👏

[IanML]

Are you by any chance near a powerful radio transmitter/radar station, high voltage lines or the like?  It is known for radio remotes to be "paralysed" by such, in which case it may happen again.

[FROSTYBALLS]

Not only the above, but National all Grid transmissions, wifi routers, wireless doorbells, etc can also interfere with the signals transmitted by vehicle remotes.

[GRB]

Thanks guys but no. We are in a small village with no high voltage about. The neighbours have been here for about 4 years and no issues. Car is used sparingly as is the wife's, her husband is disabled so can't get in this one. If anything we have improve cover years since he Rugby radio station closed, all masts now gone. I hope it was just a minor issue and is now ok

Thanks again for all your advice

[daveh_rav4]

Hi... I think that RF interferance is called 'Co Channel Interferance' or something similar.  If you have a local radio ham operating close by... that can do it. They have a licence to operate several hundred watt's of RF... the harmonic content of their transmissions could swamp the low level RF emitting from the key fob and alarm processor.

Of course the more likely fix was the other key fob... it probably re-synced the alarm processor to it's setting, there-by enabling the one that had had the Battery changed.  So, if you have two key fobs... change the Battery on them 'one at a time' and make sure you don't disable both at once by taking the batterys out at the same time.  Just a thought!

DaveH-UK

[GRB]

I think it was the second resetting system as well. I'll make sure they don't change both batteries at once next time

thanks all

Geoff