Brit6

On ‎25‎/‎01‎/‎2018 at 12:44 PM, andrewjt19 said:

Question for you... Do you remember the part number for the rear control module? I need to change mine too... Any info would help. Was the process to changing it difficult?

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I have it written down, i'll try and dig it out, but they will be different depending on model.

16 hours ago, andrewjt19 said:

I'm looking into the issues here for a different reason, but I think the problem you're experiencing is a failure of the rear control module. Do your Comfort settings reset instead of retaining them? This might be your issue. As far as my issue, I'm trying to find part numbers for the exterior antennas for the key fob alarm. It has something to do with the kessy system, but I'm not entirely sure how. I know the interior antennas are related to the keyless start, etc.. 

Yeah, that seems to be what it is boiling down to. I will try and replace my rear end control module this summer and then re-do the 2 mosfets and 6 resistors and see what happens. I'll report back.

I can help you find the part numbers, why do you believe that you need new exterior antennas?

3 hours ago, Kira Langolf said:

Thanks for your response!   Yes, the dummy key works.

 

Is there a guide to show how to get to the module?

 

PS I still have no idea why touching the tailgate handle enables the fob to function.

The module is a little difficult to get to and even harder to install back. I am not sure if there is a guide online, but there should be, i'll try and look.

As you can probably see from this thread, i had the same problem, My dummy key always works, but my handles stopped working. I replaced the MOSFETS and MELT resistors and then everything started working again.

But, they blew again and i replaced them a second time! and guess what they went one more time just last year, i have not replaced them for a third time because something is blowing them out after a couple months of use.

I am going to investigate when it take it out of storage probably in the fall. My guess is rear end control (comfort) module (I have heard these are known to fail), tilt sensor, or passenger compartment monitoring sensor.

Kira Langolf: The reason it works when you press on the rear hatch entry handle is that when you do that it sends almost like a wakeup command to the KESSY module and then your key fob will work. My money is on the MOSFETS and MELT resistors, give it a go and go from there!

Believe it or not, looks like mine have blown again! This will be the 3 time in less than 5 years! 

There must be a short or something causing the issue...............

I had the same problem last fall. I ended up replacing the hood latch cable, front bumper needed to be removed and both front fender linings.

I have a similar problem that I have been working on for years, except mine is 34 on driver side fuse box.

I would trace fuse 22 to see where it connects to and go from there. There are wiring diagrams online.

Loren, are you sure? I think he is looking for the 955-618-036-05 (CONTROL UNIT- IMMOBI)

Part Number 1 on this diagram?

http://www.autoatlanta.com/porsche-parts/hardparts.php?dir=9PA-03-06&section=901-04

clarksongli: Let me know if you get this done, I have heard that once you change the KESSEY Unit, you might have to replace other components to work with the new KESSEY.

Hey markthis, the images in the first post of this thread are still working. Can you see them? Let me know if you still need more help!

I would say the rears as the power is more in the rear (62 per cent to the rear,38 per cent to the front)

I am going to say that possibly my passenger interior monitoring sensor has a short, I have had my heated seats tested at the dealer and they are all ok.

My fuse #34 on the drivers side fuse panel keeps blowing (sometimes once a day, sometimes once a week, etc) (34 Passenger compartment monitoring, seat heating 5 Amps)

I changed the 2 FETs on the weekend and all the door handles, and the rear bumper are working again. Now we will see for how long they will last.

Thanks, im going to go try it now, will report back after.

The problem with these is they break and most of the time you actually have to replace the piece that is under the carpet which snaps into the top clip.

In the tutorial you have these specs:

Red lead on SOURCE (right leg), black lead on GATE (left leg) = OPEN CIRCUIT

Red lead on SOURCE (right leg), black lead on DRAIN (TOP or back pad) = .5V to .8V

Is that the results of good FETs or leaking FETs?

did you measured the FETs? Was there any leakage? If any of your handles or interior key sensors work then your FETs AND resistors are good.

This is interesting!

First time happened to me today I keep getting "Key Not Found" and the car willl not start with the DUMMY key, of course the door handles don't work anymore.

Could somebody please provide the part/mfg# for the fused resistors?

I've replaced the MOSFETS several times and the keyless entry/battery drain isuues go away for several weeks, but eventually return. So I would like to attempt to change the 6 resistors as well to see if that solves the problem.

Much appreciated!

There is one relay under the dash which controls all the seats.

There is one module under each front seats, I think it is yellow.

You will need to remove the bolts on the seats to access the module.

I might have some documentation if you need it.

Well Cayenne was parked for 2 days, went to touch this morning (of course not working) tried the button on my remote (not working), had to unlock manually with key, not even 5 seconds passed after I opened the door and the alarm went off, quickly started the car with the DUMMY key and that works fine.

Something is messed up, not to mention my blower motor is on it's way out....

OK, I will take a look at the FET's again.

The Entry and Drive handles were working perfectly everytime for 2 months after I solded the 2 FETs and 6 Resistors. It only stopped working after I brought my Cayenne to the dealer for my heated seat blowing fuses all the time.

It seems to work every now and again.

It could be that i have a faulty rear end control module which actually stores all the settings and that is what communicates with the KESSY.

when you soldered the FETs in, if the gate portion(the backing plate of the semiconductor portion) isn't super good, then it can cause irratic behavior as well.

Was the solder job semi hacked up? you end up putting a lot of heat into the FET to get the solder to flow....unlikely to damage it due to heat, but if it wasn't sitting clean on the board with a good joint, you could be having issues there.

If the solder job was good then i'd start looking at the handles and other interior modules like you mentioned above.

It seems to work every now and again.

It could be that i have a faulty rear end control module which actually stores all the settings and that is what communicates with the KESSY.

Wow this is getting stranger and stranger. The entry and drive stopped working again, i went into my MID (Multi Information Display) and went to comfort and door lock just to check the settings, everything looked ok. Once i exited the car, my handles worked again (I didnt change any settings). It worked on and off for the day, then stopped completly, i tried the same thing on the MID and the handles are working again.

What to try next?

I will try and replace the FETs again.

My front door sensors and handle buttons were working for about 2 months.

My rear door sensors never worked, and the rear handle buttons always worked.

Rear hatch bumper sensors and DUMMY key also always worked.

Can't believe i've had the Cayenne for 3 years and I am still playing with this.

I tried re-soldering 6 new resistors and it has the same problem even after I replaced them, I checked the old one for short and it looked like they were ok.

I wonder if I should try changing the 2 MOSFETS again??

Ok so all my antennas are short again! The PIWIS is able to communicate to the KESSY module and I am able to start the car with the dummy key but none of the door handles or trunk sensors are working.

I guess I should try and re-solder 6 new resistors but I have a feeling that either one of the handles or one of the sensors is shorting the KESSY unit. Strange.

I had my car at the dealer for a heating seat fuse blowing all the time.

They mentioned to me that the PST2 can still not communicate with the rear door antennas and that they are showing open circut.

Both my front door handles work for unlocking/locking, and my rear door handles will lock but not unlock.

nope not normal. The MOSFETs control power to the antennas, so if one handle is working then it probably isn't the KESSY.

Chances are you have a bad handle/antenna but without a durametric it will be tough to tell for sure.

Congrats on getting the KESSY back up and running....I hope my PNs and DIY were semi helpful.