Kessy system unlocking on passenger side (RHD car)
09-13-2018, 08:05 AM
#1
Kessy system unlocking on passenger side (RHD car)
2004 Cayenne S
Damaged Kessy module repaired (just the MOSFETs) as described in a separate thread about a huge power drain. This solved the problem at last. No more overnight drains.
But the Kessy module is acting strange - and now my question is more 'why do I NOT have a drain?'
It hasn't worked for a long time but I never used the keyless entry so... In fact, I remember when a Porsche dealership did a diagnostic a few years ago they mentioned the antennas or handles (I forget) needed replacing.
The drivers side (again, this is RHD so the passenger side for most of you) doesn't open at all.
But, and this is the strange bit... the passenger side opens without me touching it. If I lock the car and walk around to the passenger front door, it unlocks.
If I lock the door with the fob from the passenger side, it unlocks straight away.
While I was at the garage discussing it today after getting a load test done, it also seemed to be locking/unlocking itself as we talked...?!
As I understand it, the kessy module goes to sleep. And the door handles have proximity sensors. When you place your hand on/near the handle, that wakes up the kessy module which then scans for the fob.
Obviously the proximity sensors use some power but it must be minimal.
But if the kessy module is unlocking without me touching the handle (therefore without me telling kessy to start scanning) does that not suggest it is scanning all the time? I would imagine that would take more power?
But since I changed the MOSFETs, I haven't had a single drain. I left it 60 hours and it was fine (gone down a bit, but started fine). And it's started every day since.
I don't understand how - unless the scanning doesn't use much power? Or maybe it stops scanning after a while? (But if so, why does it start scanning?)
Could the proximity sensor on the handle be sensing me stood a foot or two away?
I can live with this, as long as it doesn't drain the battery, but if I can fix it easily - all the better!
Thanks
Damaged Kessy module repaired (just the MOSFETs) as described in a separate thread about a huge power drain. This solved the problem at last. No more overnight drains.
But the Kessy module is acting strange - and now my question is more 'why do I NOT have a drain?'
It hasn't worked for a long time but I never used the keyless entry so... In fact, I remember when a Porsche dealership did a diagnostic a few years ago they mentioned the antennas or handles (I forget) needed replacing.
The drivers side (again, this is RHD so the passenger side for most of you) doesn't open at all.
But, and this is the strange bit... the passenger side opens without me touching it. If I lock the car and walk around to the passenger front door, it unlocks.
If I lock the door with the fob from the passenger side, it unlocks straight away.
While I was at the garage discussing it today after getting a load test done, it also seemed to be locking/unlocking itself as we talked...?!
As I understand it, the kessy module goes to sleep. And the door handles have proximity sensors. When you place your hand on/near the handle, that wakes up the kessy module which then scans for the fob.
Obviously the proximity sensors use some power but it must be minimal.
But if the kessy module is unlocking without me touching the handle (therefore without me telling kessy to start scanning) does that not suggest it is scanning all the time? I would imagine that would take more power?
But since I changed the MOSFETs, I haven't had a single drain. I left it 60 hours and it was fine (gone down a bit, but started fine). And it's started every day since.
I don't understand how - unless the scanning doesn't use much power? Or maybe it stops scanning after a while? (But if so, why does it start scanning?)
Could the proximity sensor on the handle be sensing me stood a foot or two away?
I can live with this, as long as it doesn't drain the battery, but if I can fix it easily - all the better!
Thanks
09-21-2018, 07:20 AM
#3
I think one of your handles has gone.
There are two sensors on each handle - one proximity sensor to unlock and one pressure sensor attached to the square rubber button which locks the car.
One of your sensors is activating all the time.
An icarscan, durametric or vagcom cable will tell you which one (you can test the sensors on each handle separately) but you can work it out for yourself. Go around all four doors and press the buttons/grip the handle and see which work and which don’t work. Including the boot.
Do you ever ever get a ‘key not found’ message?
Ive been looking into this for ages as mine has a similar problem - And I’ve not got to the bottom of it.
My kessy works exactly as it should with one exception. Only one of the four black buttons do anything. The other three have no affect.
All four door and the boot proximity sensors work fine.
So, is it the handles or the kessy module? I don’t know. In your case you replaced the mosfets in the module which brought it all back to life and fixed your battery drain but you didn’t replace the resistors? I’ve not read a definitive article on what the mosfets and resistors do and I’m not confident enough of my own soldering to try to replace them (The part numbers would be handy if you have them).
Replacing the handles requires the removal of the door liner and carrier. And they are about £130 new.
Let us know how you get on.
Cheers.
There are two sensors on each handle - one proximity sensor to unlock and one pressure sensor attached to the square rubber button which locks the car.
One of your sensors is activating all the time.
An icarscan, durametric or vagcom cable will tell you which one (you can test the sensors on each handle separately) but you can work it out for yourself. Go around all four doors and press the buttons/grip the handle and see which work and which don’t work. Including the boot.
Do you ever ever get a ‘key not found’ message?
Ive been looking into this for ages as mine has a similar problem - And I’ve not got to the bottom of it.
My kessy works exactly as it should with one exception. Only one of the four black buttons do anything. The other three have no affect.
All four door and the boot proximity sensors work fine.
So, is it the handles or the kessy module? I don’t know. In your case you replaced the mosfets in the module which brought it all back to life and fixed your battery drain but you didn’t replace the resistors? I’ve not read a definitive article on what the mosfets and resistors do and I’m not confident enough of my own soldering to try to replace them (The part numbers would be handy if you have them).
Replacing the handles requires the removal of the door liner and carrier. And they are about £130 new.
Let us know how you get on.
Cheers.