Key works, fob buttons don't, PAS module issue? - PCB guru advice required
I've had my 07
Cayman
for around a year or so and when I first got the car, the trunk and frunk buttons would successfully open those lids. Not the door locks though.
I changed the fob
battery
and they stopped listening to the fob (I only have one key, noted as Key 2 on the dash display). The doors still don't unlock from the fob. The
battery
does function, I can see the
led
light up when i press the buttons.
The physical key does unlock the door, and I have to put the key in the ignition within about 5 seconds or the alarm starts going off. The key still starts the car. The door sill switches still can open the trunk/frunk.
So for the past year, it's been a minor inconvenience in that I have to use the physical key for locking/unlocking but nothing that stops me from using the car.
I had a spare couple of hours the other night so thought I'd bite the bullet and delve a bit deeper.
Checked all the fuses in the kick panel - OK
Removed and tested each of the relays above the kick panel - OK
Removed the PAS module to check the
plug
/wiring for any visual damage - seemingly OK
Opened the PAS module for visual inspection - found this in the bottom right hand corner...labelled U15 (don't know what this is)
Compared to another photo I found online, mine defintely looks crispy.
There is nothing on the backside of the board in this location.
Anyone know what the U15 means? It "might" be noting an integrated circuit according to some brief research I did.
Does this look like something that can just be reheated, wiped clean and re-soldered?
Cheers,
Julian
Key fob transmitter and
battery
handle the door lock, frunk, trunk releases. The
battery
needs to be good, and this circuit needs to be "paired" to the car, of course.
The alarm after the key open is expected - the immobilizer is a separate device and works with a separate chip in the key. It is NOT
battery
powered. I believe it's basically RFID which means the coil in the ignition energizes it "enough" to provide the code needed to clear the alarm and start the car.
It's entirely possible that the transmit board in the key is worn or bad or something. These keys are known to lose buttons so this part can be replaced. The immobilizer chip is a different animal, and if you plan to replace the rest of the key assembly, it's VERY IMPORTANT to pull that chip from your existing key and put it into the replacement one. Not doing so will require dealer work and cost a lot, from what I've heard.
I don't think the PAS module has anything to do with the problems you have reported. I think you just need to fix/replace the transmit-side of your key. The immobilizer is working as expected... just be sure to grab that if you replace the rest of the key.
Hmm, thanks. I'll dig back into the key, double check avarything looks clean.
Many have had good luck with replacement Ebay key bodies. I'd say you could try that and be sure to grab the immobilizer chip. See if that solves it?
I might also suggest clearing the keys from the car, as the implication is that there may be another key out in the wild that can open your car. The likelyhood of this being a real threat is low, but it may be easy enough to do while you swap to a new key-body?
Why am I remembering there is a "reorient the key to the car" process as they can lose their connection somehow. Don't have my owner's manual handy. I seem to recall the process is to insert the key into the ignition, turn the key to the accessory stop, don't start the car, and then push all the fob buttons. I may have the sequence wrong but I'm pretty sure I read about this kind of process. Check your owner's manual. I believe it's in there. If I'm mis remembering, you have nothing to lose. Keep us posted.
The u15 on the PCB looks like a bare footprint where a component could go, but isn’t installed. Yours looks like the solder paste/flux got a bit corroded on the large pad. Seems unlikely it’s causing a problem, but you could try cleaning it up with some alcohol either way.
I have tried this previously but I had the remote apart again looking at it for dead bits (none visible) so I'll try it again. Thanks
Interesting, I'll dig the module back out and give that a shot. Thanks
