Remote unlocking only works 1/15+ times when pressed

Just wondering if anyone has had issues with the remote unlocking on their 996. It used to work flawlessly, but over the last year or so the key remote doesnt unlock the car every time its pressed. I can see the light under the windscreen flashing, and the light on the remotes are flashing when pressed but the car just doesnt lock/unlock/open-boot reliably. I have to hold down the button, or press it 15+ times sometimes to get it to work. Ive also tried with both keys, which have new batteries. Has anyone seen this issue before, I have no idea what could be causing it. I have a feeling its the car as the keys are pretty simple and do unlock the car eventually.

If you can see the red light on the dash illuminating when you press the fob buttons then the car is receiving the fob signal ... it's just not doing what it should . Fault code read out with a tester .. on alarm actual values confirm the car is seeing the fob buttons pressed .. you press them and the values switches to on basically .. From there we start thinking alarm control unit .. its getting the signal from the sounds of it but its not doing what it should .. lock / unlock .. Actual values for door lock positions / ignition key position need to be checked .. Ie drivers door open .. or it thinks it is and it wont lock .. if it thinks the key is in the ignition .. a faulty ignition lock .. it wont lock . In essence .. many things to check on a tester before pulling the plug on an alarm cu replacement . If the car is a Cab .. water leaks on the n/s due to blocked drains kill the alarm cu or cause many issues .

Oh wow thanks @deMort this is so much to look into thank you very much for the thorough response. So...to clarify the point around the dash red light illuminating when i press the button, this doesnt happen all the time. I can press the button (or hold) it 5-10 times and the light doesnt flash. Then it eventually starts flashing and I have to keep pressing the button and it will eventually lock/unlock. As far as reading for fault codes, this isnt something I've done before. Is there an inexpensive way to do this or should i refer to my garage? Seems like this is the best diagnostic approach to determine which side the error may lie on.

Aghh ok .. if there is no red light on the dash with key fob pressed then its more than likely the fob isn't sending the signal .. Start with replacing the key fob battery if you haven't already .. CR2032 .. If that's no good i expect the buttons in the key fob either have a bad solder joint or the switch part is contaminated .. which is why you need to keep pressing it to get a signal to the car . As per this post you can get them repaired .. http://911uk.com/viewtopic.php?t=150572 i'm unsure the cost of repair verses a new one is viable but that's your choice . Fault codes and you need a dedicated system tester .. many threads here about foxwell and others .

I had replaced the key battery a couple months back but I will do so again as the post you linked mentions that the battery can be drained quickly. Also this is happening with both keys, though i just tested the spare (which hasnt been used in a while). Will change battery and report back tomorrow, but could it really be the battery if the red light on the key flashes bright everytime still when pressed/held? I will check with fresh batteries in both keys tomorrow, if both keys dont work i would doubt the solder could be ruined on both as ive literally never used the spare key. Also thanks for the tip of a cheaper key repair vs replacement. Thanks i went into a little deep dive on the fault code reader, i thought they were like £900+...was surprised to see that theyre not. Got a Foxwell 530 from their official site, no idea how long it will take to get here. Guess I've got a few things to work through tomorrow, and when the reader comes. Thanks again

The fob light will flash to say its sending a signal .. it doesnt mean its the correct signal though .. the car will acknowledge the correct signal by the light on the dash flashing .. as it does not its not receiving the correct signal . To me .. its a key issue but i will say there is an antenna in the alarm control unit .. technically a fault with this would stop a signal .. the usual test for this would be to move to the passengers side .. hold the key at the base of the window .. then try it .. the alarm control unit is under the passenger's seat so you are basically getting as close to this as you can . With a tester .. i can look at fob values .. i can press a fob and the car will tell me if its seeing the signal or not .. i don't know if the foxwell will do this as obviously i use Porsche testers . For me though .. i would still guess at a key going by the odds of what i have seen over the years .. anything is possible but its in reduced amounts to the almost impossible once in a lifetime fault . In other words .. an educated guess .

If you can, test the fob batteries with a meter. Quite a few of the Ebay ones are out of date, fake or flat as a pancake on arrival. Check the vehicle battery too. As daft as it sounds, even when cars seem to start normally, I've had issues with BMW's and Jags where the CL wasn't working down to low vehicle battery voltage. If you haven't got a multimeter, get a cheap one, they're so useful for troubleshooting electrical issues and only a tenner or so if you don't need super accuracy.