Repairing a Renault Laguna Card KeyA common fault with these keys is that one of the buttons stops working. You can tell when this is a fault with the key rather than the car because the led stops flashing. If both buttons have failed then first try the obvious and test the battery and make sure the contacts are clean. If so then you need to resort to one of two drastic solutions; buy another one (about £130) or repair it.
This is the type of key we are talking about, it is the type with two buttons and the safety slot in the end, not the proximity type. There may be other models that use a similar key, I have seen one with three buttons for instance, but I don’t know if they have the same weakness. The fault with these keys is that they use surface mount micro-switches and the “lock” one seems to be on a vulnerable part of the board which perhaps flexes and it drops off. Often you can hear it rattling loose inside.
The tools you will need are a good strong Stanley knife, a soldering iron with a very small tip (1mm or less), some long or curved-nose pliers, a strong magnifier and some super-glue.
The first task is to get inside. These are not clip-together cases, they are glued all round and on some internal ribs as well. On the photograph of my one below (click for a larger image without my annotations), I have marked the glue lines in red. The blue dots are unglued guide posts. With a strong Stanley knife and starting at the point marked “A” you can carefully cut along the edge, try to cut if you can as it doesn’t split very well—and watch your hands as the blade is liable to slip. When you reach the first bend “B” go back and do the first internal rib, then you can move round peering in the crack to see what to cut next. Be careful not to damage the components or the circuit board. A close inspection of the pictures shows the things to avoid, it is really a matter of patience, care and brute force.
As you can see, mine opened upside down, so the next step is to cut under the battery clip to separate the circuit from the case; I used a small kitchen knife to get in there.
So you should now have all the parts laid out including a loose button switch. This switch has a contact on each corner, two fold-under lugs to hold it together and two other lugs to help it stick to the board (ha! ha!). Sorry, the resolution of our camera is not good enough to see this detail. Near the centre of the circuit board you have a corresponding space with two pads on the earth plane at the top (arrowed blue), two on a track leading to the IC at the bottom (arrowed black) and two isolated holding pads (arrowed red). The orientation of the switch is important, the wrap around lugs MUST be to the sides.
With your fine tip soldering iron, clear up and tin all the contacts on the switch. Similarly clean the circuit board pads. You are well away from any delicate components here so there is not a lot of risk. Make a small solder bead on each pad. When I say small I mean small; I used a jewellers eyepiece to see what I was doing, scary with a hot soldering iron inches from my face.
Now lay the switch on top and test that it works by holding the battery in, and pressing the button. If you get the switch the wrong way around, the light will be on without pressing the button. Satisfied that it works you can solder the switch into place—holding the switch down with long pliers, touch the soldering iron to each corner and the top/bottom edges to get the solder to bridge the gap in six places. You may need to go round more than once as the component beds down to the surface. Test it again. As a final touch, I dribbled a bit of super-glue under the switch as an attempt to hold it more securely.
Now clean up the plastic parts with a knife, removing all loose bits and get the halves to mate together tightly without the circuit. You will also need to clean up the plastic part of the battery clip. Lay the circuit into the back cover, there should be two positioning pegs to hold it in place. Apply a drop of glue to the battery clip to secure it and leave it for a few moments to set. Finally run a bead of glue around the outside edges and the main internal rib, bring the parts together and clamp (clothes pegs) or weight it until it sets. How many of the original lines you do depends on if you are likely to want to undo it again but I would suggest omitting the front of the battery clip.
For the technical, the numbers on the components are: the big round piece (transmitter coil?) is 50751, the DIL package (encoder?) is Phillips PCF7947AT with other numbers 16793102 and DnD00350. The small silvery unit (oscillator crystal?) has EPC05, R727 and M5MN. A Google search didn’t turn up much.
Webmaster
Hello
Can someone over here tell me where can i purchase the software for renault that start their car with a card?
Thank you so much
http://www.car10.co.il
Joseph Hazbon
This is a fantastic bit of knowledge, carried out the repair to the keyfob as described and it now works a treat. Be very careful when cutting the case open as some force is required and you don’t want the blade of the stanley knife going to deep into the case as it may cause electrical damage.
Managed to undertake the repair with a bog standard soldering iron although that a smaller one would have made the job easier. Using a magnifying glass as mentioned is also useful just to understand exactly what you are trying to achieve. Once you’ve cleaned and tinned all the contacts I found it useful to hold the switch in position with the end of a small electrical screwdriver (after taking out the battery) it depressed the button but it held it in place with some good pressure so the switch sat down nicely when the joints were touched with the heated iron.
Mine is just pegged at the moment waiting for the superglue to set but it works and it’ll be good to go in the morning.
Thanks very much for posting the info, hat off to you, cheers Ben
my name is peca and a come from kosovo and i have one laguna and i have 3 carts bat two of them are brocken thej dont open the car and i find thos words that you sead and i will open my carts lonly thankyou nahe a nice night
hello! sorry for my bad english! know enibody if i can repair my laguna’S 2 card with 3 BUTONS ( WITH HANDSFREE BUTON)?
Does anyone know if it’s normal for the Renault key to become very hot just when driving? Does this denote a fault? Is it dangerous?
Thank you!
Hi Margareta, mine gets fairly warm and I don’t think the heat is generated internally but because it is fairly close to the heating system. Can you remember if it got hot in the summer with the AirCon on?
Hi, do you know how i can lock the car until i get the key fixed? thanks
Hi Karis, the easiest way, and it still involves a bit of contortion, is to open the back door, lean in and operate the lock button on the central console then slam the back door. Some have said that this works from the passenger side front door as well but I am not sure that it does.
Ahh thanks, mine wont do it from the passenger door but from the back door it has, bloody things it’s obviously a massive issue they should make them better!! Brilliant site!
Absolutely superb info. Was tough taking key apart- v sharp knife a little controlled force & patience paid off. Re soldering i found it easier to go to local electronics repair guy who did the job in 10mins & charged me a fiver! Cheaper than buying iron + solder etc. Have just glued all back together and clamped with pegs. All working fine. Renault wanted 180+vat and would have had to wait 2wks. Thanks to this site info i sorted everything in couple of hours for £5
hi,
when I was opening a card, I was not carefull enough and I damaged some conductors. Does somebody have a schematics of 2 buttons card?
JV
Could someone please help me with my problem. My card locks and unlocks my car, but it wont de-imobilse it, the red light remains flashing, which means it wont run. Is this a problem with the card, or the imobilser?
You should have 2 cards. If both fail in the same way I would suspect the imob. If only one then it would be the card gone faulty.
Hi great site wonder if anyone knows why laguna dash stops working speedo rev counter and fuel guage no lights at all
thanks sam 04 laguna
Hi Sam, I would check all your fuses first but I recall that I had to have my dash replaced at 18,000 miles, but can’t remember the symptoms. It may be worth going through the dash test sequence that I mention in tip number 2 here.
Great advice. £140 saved ! All the best.
o.k hello.thanks 4 the info on keycard.worked a treat.i got another huge problem.my car ran out of desiel and ever since then i cant get rid of the warning stop lights.??is there a wy of reseting the ecu??
Hi 117 – have you tried the suggestion in paragraph 2 here
Hi all i have bought condutive paint used for fixing dry or damaged links on circuit boards and screen heating element and also poseses a strong glue to hold parts in place and i have fixed two keys with this using the method here and both work graet and have not had a problem since the paint cost me £6 pounds on ebay and has a very small applicator so its not hard to use at all cheer great site and fix 😉
Hi many thanks for the card repair worked a treat. Can you add that if you hold down the center console lock switch with the driver (or any door) door open after 8 seconds the car dead locks then you can close the open door and walk away with the car securely locked. Then do the fab repair.
Thanks Henry