Immobilizer issue?? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

My 1998 base Boxster has 2 key fobs each with 2 buttons (one for the door locks and one for the rear trunk). They both worked OK but just OK....meaning that I always had to be standing very close (within 2 to 3 ft) to the car for the buttons to do their thing. Seemingly suddenly BOTH key fobs no longer lock/unlock the doors and no longer open the rear trunk. One day they worked and the next day they don't anymore. Both have brand new Duracell batteries (tried several new batteries in each). Both fobs little red lights blink properly when pressed but nothing else. The keys work fine in the ignition and the car starts perfectly...... Am I correct in thinking the fob's buttons send a signal to the "immobilizer" or is there some other system that controls the remote locking/unlocking? Is there an antenna of sorts that receives the signals from the fob's button pressing? It's not a terrible thing to turn the key in the slot to lock/unlock the doors but I'd like it to work as it previously did without spending a fortune of taking apart the whole car...LOL Any insight would help...thx

Smallblock454 should chime in here, he has a business that bases on solving these problems. You could try to do a synchronization. It happens that one key looses ability to open, this is because of a weakness in the frequency. But two of them in the same time ...? Resynchronisation procedure for Porsche 986, 996 and 980 • Open the driver's door, get into the vehicle and close the driver's door (the passenger door must also be closed). • Switch on the ignition. • Switch off the ignition. • Remove the remote control key. • Within 5 seconds, press the open/close button on the remote key (key symbol) and hold it down for 15 seconds, then release. • Press the open/close button on the remote key (key symbol) and hold it down for approx. 1-2 seconds (i.e. not too briefly). If necessary, try 2-3 times in succession. Allow a pause of 10 seconds between each attempt (child lock). • The central locking system should now lock the vehicle (resynchronisation successful). • Press the open/close button on the remote control key (key symbol) to open the Porsche using the central locking system.

I tried that process a few times with no success. I'll give it another try in the next couple of days......but not sure IF that procedure to perform synchronization is applicable to my 26 year old Boxster. Is that procedure in the owner's manual or the shop manual for the car...or just for newer Boxsters?....

This should give more insight And I would work through this as well

Thanks but I'll just use the key in the door to lock and unlock the car. As long as I can start the car that's really all that matters. The the various procedures on that referenced document might as well be written in a foreign language........LOL....but thanks for posting them. I was hoping that it was just a fuse that needed replacement..... .

Have you managed to resolve this? I accidentally violently hit the opposite side of a concrete deep ditch in the road with my bumper. Now my central locking no longer works. No communication between the key fob and central locking/alarm. When I unlock the car with the key the horn beeps twice. From what I remember when I replaced the passenger door actuator, this is a fault signal. I'm finding quite a few threads online that describes this scenario and attributes it to the knock to the bumper. Porsche centre body shop "experts" are adamant that it is impossible. ("In my 30 years as a panel beater, I have never heard of this") I have only done 102 000km in my 2001 986S. And kept her in perfect shape.

My first guess would be that something came loose. I would check connections to the control under the seat. First disconnect battery!

My car will be coming out of winter storage on April 1st so I can't say IF IT "MAGICALLY" FIXED ITSELF over the past 4 months......but I kinda doubt it. I'm not going to mess with it myself and not of the mind to pay anyone to troubleshoot/fix it. My car is in beautiful shape after almost 28 yrs but has a few signs of aging....Door lock remote, vent system occasionally spits tiny foam pieces, could use new shocks, radio kinda sucks etc etc....BUT it looks great and runs well during the summer months and the usual 4,000 to 5,000 miles I drive it (TOP DOWN) each summer. (w/105,000 miles) With a "book value" usually hovering around $3,500 to $3,900 it doesn't make sense for me to sink a lot of money into it. So IF I can lock the car manually I'm fine with that. If it's magically "cured" and the key fob locks the door I'll be sure to report back.

Well.....I took my car (1998 Boxster) out of it's winter "hibernation" today and it DID NOT magically fix the key fob issue, that suddenly began last November. (I'm just assuming the issue is with the "immobilizer" or maybe the "central locking system") My 1998's key fob still does not lock or unlock the doors, or open the rear trunk. The car starts fine with the key, the fob red light blinks as it should when trying to open/lock the door or open the rear trunk but no luck. I tried both fobs w/new full strength (tested) batteries but still "no joy". I'm just wondering IF there is a fuse that might be blown. Does anyone know IF there is a fuse that's designated to the door locking system? IF SO, any idea which one and would it be in the driver's foot well or elsewhere? Just wondering if a blown fuse could be my issue? I've tried all the previous tips to no avail.....the thought of bringing my 26 yo car into a Porsche dealer to "diagnose" is VERY SCARY.....especially at their current shop rates that might require a "second mortgage"...lol. (at least the key still works in the door and ignition) Thanks, R

M53x itself has a 10 Amp fuse at the housing, you need to remove the left set or use an endoscope to check it. Mine was ok but not seated completely. I recommend disconnecting the battery before you start.

I'll see what I can do.....removing the seat isn't easy. Those fasteners have been on for 26 yrs.....very difficult but I'll try again...thx

Quotes source post: 669856

E12 Torx (female), use an extension

Thanks.....