Remote Suddenly Stopped Working

Searched forum, couldn't find similar problem. Looked in the user's manual, nothing. Went out a couple days ago and I can't get the car to lock/unlock OR open the hood no matter how hard I press on either button. LED still blinks just fine when either button is pressed even lightly. My remote always had trouble with the lock/unlock button: I would have to really push hard on the remote button to get the car to actually lock/unlock, even though the LED on the remote would blink pushing the button lightly. I figured it was the "broken trace on the PCB" syndrome, but can't find posted picts of where on the board, and there are traces under some of the parts which I don't want to have to unsolder if I don't have to. So I've just lived with it. But the front hood button still used to work just fine when pressing it lightly. Battery in remote replaced. Any ideas? Is there a way the car can forget the remote code and needs to be re-learned? Or could it be the traces on the PCB still?

Try locking and unlocking the car with the key in the drivers door. Then stick the key in the ignition to the on position. Then press the key fob lock/unlock button.

Quotes source post: 9502452

Thx Function12, I'll give that a shot when I leave for lunch. I'll report back later today.

Nope, didn't work. Any other ideas floating around other than going into the dealer and paying thru the nose for a new remote?

Mine quit about three years ago. I don't think it is repairable. Maybe somebody can confirm if they got a non-working remote to work after reprogramming because I was told it is impossible for the car to "forget" the remote coding no matter the battery status of either car or remote. I think the remote circuit board fails and it's toast.

You can't reprogram a remote. Once it's paired it cannot be changed. Hate to say it, but you need a new remote. I've had it happen to me too. Sorry.

Oh booooooo. That's dealer territory I've got to venture into now. $$$. Maybe I can get most of the parts thru Suncoast and then take them into the local dealer to get programmed. Might as well get a new key, fob, and everything else. I only got one key with my car, so this dead one can be a spare. Trying to look on the bright side.

Had the same issue and went through the same trouble shooting. In the end it was a new remote from teh dealer. Check Suncoast to save some money and then have your local dealer swap over the key and reprogram it for you. -S

Quotes source post: 9505294

Is it possible that the battery is low or dead

Quotes source posts: 9505427, 9502244

OP indicated LED blinks fine and battery had been replaced below

Assume your CAR battery is fine? Occasionally this is the first warning of a weak car battery.

It's the fob. I have exactly the same problem/symptoms right now, except, for at least a little while longer, it works with two fingers pressing on the button hard. It has been slowly going down hill for months. To all who have responded - it is NOT the battery in his car or the battery in the fob, or programming, or anything else. The fob circuit board where the pressure connection hits just wears out after a while just like many electrical switches. If you are an expert micro-electrician you might be able to figure out how to fix the worn connection. Otherwise your feared trip to your local dealership is your alternative. Since I have both original key fobs, and the other one works perfectly, it is the fob.

Hate to admit it, but I sprayed brake cleaner on my opened Volvo key fob and it sprang to life again. could also use electrical contact spray. never seen a Porsche fob opened, but probably similar . may have nothing to lose...

But his light flashes just fine on the remoteZ wouldnt that say the button is working?

Quotes source post: 9506146

As does the light on mine... It is a PORTION of the circiutry that is no longer working. I tried cleaning the contacts but it made no difference. The fob integrated circuit board is a very complex piece of electronics. It performs MANY functions, even though my MY99 has only a single button. It is a lot more complex than a flashlight... The little flashing light is just a signal to YOU than the battery is working. The light has nothing to do with the coded RF challenge-and-reply signal being transmitted from the key. If it did, then you would not be able to lock/unlock the car by simply pressing the buttom even when the key is in your pocket or you are facing away from the car.

you can also try to reset the fob....insert the battery in the reverse polarity position...leave for a few seconds, then reinsert the battery correctly. The fob can be re-programmed as well....these fobs can "lose" their codes for several reasons, for example not being used.

The only way to reprogram the FOB is if you have its original 17-20? digit number to put in the car's immobilizer and the equipment to talk to the immobilizer. If it is the switch you can replace it. Part #CKN9193CT-ND http://search.digikey.com/scripts/Dk...T-ND&x=26&y=17

http://www.renntech.org/forums/topic...opped-working/ From the above link" "Dave: There is an interesting article in the June 2010 issue of Excellence Magazine entitled: "Fob 4 Less: Fixing a modern Porsche key for less than $3 bucks". The article describes rescuing a dysfunctional key by replacing a couple of small, inexpensive momentary switches. Looks relatively easy to do and since the electronic functions of your key are already messed up you don't have much to lose. I have one non-functional fob, but since the other is working I haven't tried this idea yet. I did call the dealer about a replacment. They offered to solve the problem for $375. If you go the diy route please let folks know how it works out. The article lists the source for the momentary switch as: www.digikey.com , phone # [phone removed]). The three switches (this is a reply to a targa owner 3 switch Remote) are normally off (part # CKN9193CT-ND). The web link is: http://search.digike...CT-ND&x=27&y=19 "

Quotes source post: 9507609

Thanks for all the input guys. I'm an electrical engineer, but figured before I go in head-first and rip stuff apart I'll get as much info from others who have gone in before me. Learn from other's accomplishments (and mistakes!). I'm almost positive it isn't the switch, 1) the LED is still lighting just fine, and 2) it's an SPST switch (basically one contact w/ on and off positions), so I know there isn't two circuit paths (one for the LED one for the radio). So if the LED lights, the switch is fine. I heard (but cannot find a posting) that the traces on the PCB can break when the PCB flexes when the button is pushed (bad design). That's why pushing hard on the button will make it work sometimes; your flexing the PCB, allowing the traces to make contact. What I can't explain is why BOTH buttons suddenly stopped working, when the trunk release didn't ever have to be pushed hard. But, I don't know the circuit or how it's laid out, so I can't say it still isn't the traces. I'll go into the fob sometime today or tomorrow and root around. Even if I jack it all up I can still drive the car since that little RFID 'pill' (or whatever technology it uses) is separate from the remote PCB and buried inside the key fob. Worst case is I buy all new PCB and fob, transplant the RFID, and get it programed at the dealer. I'll write up a DIY should I be able to repair it and post it on the forum.

Quotes source post: 9509174

PUT DOWN THE SOLDERING IRON , step away from the bench and call a TECHNICIAN!

Interested to see how this works out! (where's garrett when you need him?)

Quotes source post: 9512150

LOL!! I know what you mean, I know a lot of engineers who fit that bill! But, rest assured, I am not one of them. I've been soldering since I was 3 (where was CPS! Lol!). My folks would buy stuff for me to take apart too. They figured that out after I started taking apart everything else in the house, including my rocking horse.

For what it's worth, yesterday I tried to fix my remote the same way I fixed my son's PS3 which was to heat the PCB with a heat gun and attempt to re-flow the solder (assuming it might be a cold/broken solder joint). With the remote, it's difficult to heat the board enough without melting the battery holder. Anyway, what worked with the PS3 unfortunately did not work on the pos Porsche remote.

I had both of my remotes suddenly stop working within months of each other. I would put in a new battery and they would work fine for several days then slowly degrade until they would stop working again. If I pulled the battery out for several hours and put it back in the unit would work just fine for a short period of time then die. Something was constantly draining the battery. This is a classic failure mode for a ceramic chip capacitor. The dielectric breaks down because of poor chemistry or processing and allows current flow. Finding the offending cap is pretty difficult so I just purchased a new Carrera GT fob, put in the blade from one of the old fobs and had the dealer program the car for the new fob.

That's consistent in an undesirable manner!

Ok, so here's the deal. (for those who don't want to read it all, I need a new remote, it was unrepairable). I looked at the PCB under the microscope and did indeed find that the pin-to-pad solder joint on many of the microcontroller IC's pins were indeed broken. That explains why you have to push hard on the button to get it to work - when you press hard you flex the board so all the intermittent connections are made. The scopes camera wasn't available or I'd have posted pictures. I was hoping that was it, so it was resoldered. No go, it still didn't work. I read what psamead has written, and while I know that the dielectric properties of ceramic caps (the only type of caps I saw on the PCB) do age over time (both in capacity and voltage hold-off), it's only about 2-7% depending on the type. Just in case that amount of drift could cause the remote to stop working 100% (unlikely, especially when it was like a switch, working one day, not the next), I went ahead and de-aged the caps by heating them back up to their Currie point (roughly 125C). Again, no dice. At this point it's most probable that one of the components completely failed. If I had a schematic of the board I could replace all the cheapo parts that could age or die (the caps, couple transistors) just to see if that could fix it. I could measure the caps and replace based on that, but the value read may be off considering their age and the fact that most are super low capacitance in the first place, used in the RF and clock circuits. Transistor, forget it, no markings on them at all. There are a couple RF-specific parts that I could not cross, so if those are dead it would be tough to replace. And if the micro went, forget about it. Unless you have the hex code to program a new micro, you're screwed. It is a common micro from Microchip, but without the source or compiled hex code, you're dead in the water. I also found out from a Porsche place that not only does the RFID "pill" inside the fob need to be programed if you buy a new fob, but they have to program car's ECU to accept the new alarm PCB too. I was hoping I could get by just buying a new remote PCB and programming it myself with a "insert key, turn to on, press the alarm button, etc." type sequence, but looks like all of that is bogus and doesn't do anything. So, I will have to buy a new fob and get it programmed at the dealer. But I'm not happy: these parts are OLD and electronics don't last forever. Hopefully a new one won't die in a year like so many other folk's had happen to them. I guess I'm calling Suncoast later today, unless someone has more options (GT remote for same cost as 996 or something, I've seen full remotes that aren't GT 'overlays').

Well you really tried hard to beat this terminal diagnosis! Thank you for reporting the process and even though it didn't work you contributed to the forum. We will probably all suffer this key failure in the future. "IMKF" Intermediate Key Failure.

I had the same problem with one of my keys a few years ago. I kept the key blade and the pill from the original key when replacing with a new circuit board and key head. $120 of programming later and I had it working again. Remember to bring all your keys to the dealer when programming so they all work. I think the ECU only accepts 3 keys at one time so the bad key tag should be removed from its memory.

Quotes source post: 9552012

I am wondering if I could swap parts from another remote to refresh my current dead remote. Can you share any details on the parts you could cross reference? I believe the smaller IC is a digital to analog converter (Maxim 5101 DAC) while the larger IC appears to be marked as Motorola thus guessing it is some sort of micro controller. I cannot quite identify the large two solder contact chip, guessing that relates to the radio since marked with "wave icon". Saw resonator? Also there is a six contact SMT part in a metal can that is likely to be RF filter as long as the Motorola part is internally clocked. Could have those two parts reversed, I am no radio expert. I would love to know the unknown chip details to replace them. Already swapped the DAC and no improvement. I wonder if the large RF part is paired to the key or not. I imagine the microcontroller has the internal binary with 25 digit remote code and everything else is generic, but not sure.