Both key fobs sending RF signal but not working

Hi all, first time post. Just completed clutch, RMS & IMS replacement on my '02 Carrera cab. Had battery disconnected over course of few weeks while working on it. Key fobs now will not work the locks nor the frunk. LEDs on fobs light up and batteries are good. I have an RF key fob tester & when hitting either remote buttons it registers 315 MHZ . So, it is definitely sending out a signal. Searched high & low before posting and tried battery reverse polarity procedure along with manual lock/unlock of doors 'wake up' procedure. No success. Car starts right up & runs great. So immobilizer is not preventing it from starting, etc. Is the immobilizer what receives the fob signal or something else? I don't post for help unless I hit a wall and that has been hit. In advance, I thank anyone who has DIY troubleshooting path next steps. Thanks, Steve A.

Happened to me in the past. ended up tasking the ECU and two remotes to the ECU Doctor. the other option is to program new remotes in the dealership. They will not do old ones (at least not here) although they can. if you go the ECU Doctor route, you will need to get your vehicle IPAS codes. edit: if by some miracle you have the barcodes for your remotes, then anyone with PIWIS can program them for you.

Thank you for sharing. Ugh that is not good!! Normally I would just live without the fobs functioning. But.....I realized well having functioning fobs is some nice insurance. Case in point when going to determine my AC refrigerant level earlier in the week I tried opening frunk to no avail. Key fob as noted a no go. Frunk door sill switch a no go. But, engine lid switch fine. Pulled frunk switch & no continuity. Disassembled switch, cleaned contacts and still no good. So, waiting on new frunk switch to arrive. And, from experience getting to that manual release in wheel well no great fun. I only post this to share how these fobs can bite you in the rear.

This shouldn't work but costs nothing to try . Insert a key into the ignition and turn on . Not start just on . Don't touch the throttle , let the key stay on for a minimum of one minute . This procedure normally is used to " reset " throttle position after the battery has been disconnected . It's a long shot but you never know .

996C438 thanks a lot for the suggestion. I tried it out but no luck. Open to all other suggestions. My last resort is taking it in. Prefer not to submit to that yet.

Silly question , both remotes worked properly before the extended battery disconnect ? For the couple of bucks go ahead and change the battery in the remotes . Check off all the low hanging fruit before getting ECU doctors involved . When you have the remotes open check under magnification for any cracked solder joints or corrosion . Make sure the " pills " are properly seated . The pills are about the size of a piece of rice . Good luck

Not silly..fair question. I think remote worked OK. It is a cab & I never lock my cars anyway so seldom used. I have had car only a couple of years. I am pretty certain the original fob worked. The spare which looks brand new I am not certain I ever checked it out. As noted, if it weren't for the frunk back up I would probably let this go. Also, if you go to sell not working fobs also come into play. Anyway, even though batteries checked out on meter 3.2ish volts I am desperate at this point. And, as you noted can't lose so put in new battery in both remotes. Still a no go. Figured as much. I am thinking receiving end is an issue because I am sending out 315MHZ signal off both remotes and all buttons. I appreciate your resilience in the fight with me. Any other ideas totally welcome!!

I did a search and there are several posts suggesting a key fob reset . Some have had success some have not . Apparently you remove the battery out of the fob and put it in backwards ( reverse polarity ) . Then push the button/s for a few seconds . Disassemble fob and put battery in with correct polarity . Costs nothing to try , after that I am out of bullets . Because you are not certain both remotes actually worked before that could mean they are defective . Like a push button switch is on its way out . Or a cracked solder joint . When you push buttons the red infrared on the center of the dash should start blinking . Does it ?

Yes, tried that reverse battery thing too early in this process following my own intense research of this issue. No luck. All solder joints look good and I will say the fact that I get an RF reading when buttons are pushed on buttons lead me to believe it is something other than fobs themselves. However, I am no expert here obviously and am just using high level problem solving. Seems like it is an interface issue with whatever receives the signal?? Also, put solder joints under magnifier and all looked healthy. The only light that blinks is the red light on the CDR-220 radio. It is blinking continuously when the car is off no matter if remote buttons pressed or not. When fob buttons pressed it is still blinking at the same pulse rate. Is this the light you are referring to & if so, should it be acting differently? Again, thanks for your passion in helping me out. Much respect.

Well with much resilience & morale support here I finally found the issue. Hope this helps someone down the road. I replaced interior frunk switch as I had made error in continuity check as there are (5) terminals. I followed another post and it was the incorrect 2 terminals that led me to think switch was bad. Out $50 is all on that. Then, went inside passenger wheel well as I had done a time last year and tried to open frunk and as hard as I pulled cable....nothing. That led me to think security issue. I found another post where key fob & frunk not open and was noted immobilizer 15amp fuse kept blowing. Last year I had some experience with this immobilizer as my cowl and rear wheel well water drain plugs were clogged leading to water soaked carpet and standing water in recessed driver floor pan where immobilizer makes its home. How did I know? Well, the security horn went off for a very long time until battery died. I am sure my neighbors loved me and am at least thankful it happened on a Sunday afternoon. Versus say in the middle of the night. I could not get hood open to disconnect battery and pulling fuses did absolutely nothing. Long story short spent a week pulling sopping wet carpet and drying out car. Disassembled the immobilizer, cleaned, dried out with no issues....well, until now...maybe. Make sure you check those drains!! Today I removed seat and worked through open window with doors shut trying to conserve battery to remove seat bolts. Last thing I wanted was to have battery die and no way to get to it. Carpet was nice & dry so H2O not a factor. Got to immobilizer, pulled 15 amp fuse on side and sure enough Blown! Replaced fuse and voila everything working as designed. Why did fuse blow....uncertain at this point. At least now I can monitor and know where to go if it happens again. In summary, if both door lock/unlock button and frunk release button on fobs not working along with interior frunk switch suspect the immobilizer under driver seat 15 amp fuse. Also, for security purposes I am guessing the manual release cable via passenger wheel well is also in locked state as well if fuse is blown.

I assume you have a cabriolet? Any posts showing the location of these drains? (Targa owner here - basically a hardtop cab.)

Yes, I have a cab. May need to research more on specifically how to get to them (I am sure its out on web somewhere) but here is what I found pretty quick: download.axd (678�610) (porscheclubgb.com) Hope above link works for you.