Keyless (kessy) entry problem fixed ! after 5 dollars and 1 hour o

[clarksongli]

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.

[Brit6]

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.

[Brit6]

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....

[ajnanyc]

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!

[clarksongli]

Resister PN is in the DIY.

But as a side note....the resistors will not fix the issue.....resistors blow when the gate starts to leak in the mosfets.

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!

You are welcome to try it, but it won't fix your issue.....the resistors are there to protect the board in an event the mosfet fails and starts to leak between the gate and drain of the transistor. If your antennae work then your resistors AND Mosfets are functional.

http://www.westfloridacomponents.com

1/4W 0.22 ohm Mini-Melf Resistor Beyschlag MMA0204-50AL0R22J

[Brit6]

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!

[ajnanyc]

Thank you clarksongli for being specific with the actual component part#. I read the post several times and no where could I find this part#.

I measured continuity of the resistors on board the Kessy and all seemed to check out fine. I am wondering why none have blown considering both MOSFETS are leaking?

[clarksongli]

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.

[Brit6]

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.

[clarksongli]

Those are good numbers

[Brit6]

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

[Brit6]

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.

Edited March 17, 2014 by Brit6

[clarksongli]

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.

Just remember, there is a reason the FETs keep blowing......one of the antenna's is drawing more power than expected. Basically there is a soft short somewhere. Start looking the antennas that are on the way out

[Brit6]

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)

[jagman1]

I just replaced the two MOSFETs and 6 resisters following this thread. All is working once again. System failed on Thursday. Back to full operation by Sunday afternoon, thanks to fast shipping and lots of info on the subject between Touareg forums and here.

I wasn't able to test any of the individual components because I lack the tools and knowledge required. So I just replaced the items in phases.

I started with the two MOSFETs (they looked easiest). After reinstalling I cleared the codes with Durametric and it still didn't work. I then replaced the 6 resistors, reinstalled, then cleared codes and it is working perfectly.

Thanks for the info

[markthis]

Hi clarksongli, Brit6,

 

First I have to say that you have shared a lot of useful information about 'how to fix the KESSY module when it’s failing you' (in my case, in an old Cayenne Turbo), and, when you are trusting yourselves enough to give it a go (to save a lot of money)! I have to say, great reading. All the given information is much appreciated!

My Kessy module is giving me exact the same symptoms/ faults as you all described. I will try to do the same, fix it myself, but I think I need your help a bit. I know this is rather an old topic, but still very useful. I have decided to make a shopping list first, because I live in Europe and I have to deal with different distributors.

 

My shopping list will contain the following, as described in the DIY:

 

1/4W 0.22 ohm Mini-Melf Resistor Beyschlag MMA0204-50AL0R22J – 6
IRFZ24NS FZ24NS HEXFET Power MOSFET International Rectifier - 2

So far it’s clear to me, but, in the DIY the images (as guiding example) are gone, so I do not know where to look at, or how to compare (I’m a noob). Is anybody well known with this manual, or is someone keeping a copy of the images? The images will help me to find the exact location on the print board.

 

A bit assistance is very much welcome.

 

Many thanks!!

Edited January 30, 2015 by markthis

[Brit6]

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!

Edited January 28, 2015 by Brit6

[markthis]

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!

Many thanks, I did not knew those are the same images. Now all is in place to give it a try :-D

- the article numbers  :lightbulb:

I have contacted Mouser Europe for the parts and yes, they have all the items in stock. The distribution depot is in France, but original it will be shipped from the US.

 

The Mouser part numbers are:

942-IRFZ24NSTRLPBF --> "Title: MOSFET MOSFT 55V 17A 70mOhm 13.3nC (Brand: International Rectifier)." needed 2, ordered 10
71-SMM02040B2207JB30 --> "Title: MELF-resistors 1/4watt, 0.22ohms, tolerance 5%, 200V (Brand: Vishay / Draloric, not Beyschlag, that was the old branding, which took me a while to find)." needed 6, ordered 20

• Price of the parts: 14 euro (all on stock)
• Shipment FedEx: 20 euro (3 working days)  :blush: shipment costs are worth the money I think.. (or I had to order 6000 pieces).

 

:wrench: I'll let you know if these parts are correct, after the repair of the Kessy next week.

 

(I had to buy a solder iron as well, so I picked the Velleman vtssc10n for 50 bucks, which a good balance between price/quality, they say on the net... :notworthy: let's find out too!)..

Edited January 30, 2015 by markthis

[markthis]

I just want you to know that I was able to fix my Kessy problem as well! :notworthy:

Because I did not succeed at once, I want to share my findings. I had to do some troubleshooting.

In my first attempt to try soldering the 2 x mosfets (transistors) and the 6 x condensers (2 times, 3 per mosfet), I experienced some issues. I did not had the time to de-solder both mosfets, so I did one, and I replaced all 6 condensers. "Wrong choice" I have to say afterwards, because the fusible condensers will be fried as soon you start the car because of the defect mosfet I did not replace. Result, I had to do all the solder again. After successfully solder the components, I checked the values with the multimeter as well. As the DIY manual described, you can measure the mosfets, but also the condensers should be tested. If you have a different value then 0.2 or 0.22ohm, replace all the 3 condensers as they are parallel switched as group. Test both groups of 3 condensers.

Second, some notes you should consider:

- Solder condensers: never exceed a temperature of 270 degrees Celcius, otherwise there is a chance you will damage the condenser. Also, find yourselves a solder Youtube education movie; I did, and some solder techniques may help you too (you work environment is scaled on 3 mm!). Good luck!

- Solder mosfets: 1) to lose them, you should set the temperature on 470 degrees Celsius (don't use a hot air gun, too much heat, so stick with the solder iron, as of my Iron of 48Watt did the job perfectly), and when you have heat the back plate, put some new fresh solder to it. This will heat up the backplate much easier and you will see that it comes off very easy. 2) to fix them, for the backplate (because I know you will fix the two legs easily), again use some new solder as well. Prevent any contacts with other components on the print.

- Resetting the faults codes with Durametric software (v6.0.7) or other, will not help you if the components are broken. I tried more then once! No luck, defect is defect. Also any activation of the kessy when repairing is finished, is not software related.

- After installing the whole Kessy module back behind the dash, you want to use the plastic dummy key for testing right? Well, if you are lucky you can. I my case, a no go. I had to drive for 20 minutes, parked the car for a couple hours, and then finally the dummy key worked, and also the door locks! Why? Or some component had to charge for a while, or it is related to security matters (Ex. 60 minutes as when removing a wrong pin code in the PSM to activate? don't know..). I have read that issues may lead to the main battery of the car below the drivers seat, but that one I replaced. What I need to replace is the second battery under the Bose subwoofer, preventing strange behavior of the electrical systems, like power fluctuations which can kill your Kessy as well.

- Before replacing the mosfets and condensers, be sure your remote key is working wireless. I have read posts where also the remote key was not working. Then some can be wrong with your key battery (should be 3.2V), or your CAN bus (which communicate with the Kessy). Also the control unit in the back can be defect, which handles too the handshake with the key. If your key is working as a remote, start to do the Kessy repair. Plan half a day to do the whole job.

- The parts I ordered as in my former post are the right parts!

- Kessy module: when trying to disconnect the two connectors under the dash (drivers site, see DIY), you will find it easy to remove the front small connector i think. The big connector needs more attention, because IN the connector the sleeve lock should be extracted first. You can do this by hand and you will find it on the back of the connector (where the cable is going into the connector). You should pull a bit hard, but gentle and the connector will come lose. Vise versa when you assembling the module again after the repair.

For now this is it I think. Best of luck, and yes, you will save a lot of money if you succeed!

Mark

Below my Kessy module under repair:

Mosfets just fixed

3 more condensors to go

Edited February 22, 2015 by markthis

[Roman Marcone]

Hey all.

 

 

I have a quick question for you. 

 

I ordered the pieces to replace on my Kessy module. Took the module out to work on it and ... those parts do not exist on mine. The circuit board on mine is a stripped down version of the photos in this post. For example the mosfets and the resistors arent on my board and mainly the Big Blue modules on the photographs are not on mine.  The model number on mine is a little different as well. ends in 7019 .. and the number at the top ends in Mx not just M as in the photo. 

 

Curious if maybe someone switched it out at some point before i bought it and got one without the 'door buttons option' (which is what im trying to get functioning again as my car has the buttons on the door handles. )

 

Is it possible to change out kessy modules and have it work? 

 

I have many issues with the car slowly happening now.. wanna figure this one out hopefully. :) 

[markthis]

Sorry for the late reply, but what if the door buttons are not original? And your module is? I think you should find the Kessy module with the Durametric software first. In my case the module is identified as KESSY. By the way, the KESSY module is not working if all depending other parts are installed too, like antenna's, the right CAN bus, wires.. name it... And if the car is prepared, and you are able to switch the module for an other KESSY, then you need to re-program the KESSY for your keys as well..  :oops:  :wrench:

[Kenatic]

[bTW: I think Markthis is referring to resistors not condensers)

 

Thanks everyone for contributing!  I have the same thing happening on my 2004 Touareg V10 TDI. Buttons on door handles stopped working and the automatic open (pull driver door handle twice stopped working, and the rear lid window stop working, then magically for a few days worked, then never again).

 

As of this writing The Mouser parts are still available (April 25th 2016).  

 

Interesting enough.  The battery under the front seat (accessory battery) keeps getting massively drained and eventually fails and it started happening after the kessy unit failed... I will do the repair to kessy as indicated -- also I replaced the front and rear batteries.  I have to replace the front battery about once a year, until I read about failures of the kessy(!), hopefully this will fix it.  I will likely have the local printed board assembly service in Bellevue Washington USA to the soldering PCA - Printed Circuit Assembly for $50).

 

The alternator been acting up as the front battery went dead (lost a cell), eventually brining the 'Egg to a stop, and I replaced the battery and now the alternator it won't charge at all, before replacement it would output 14V, but started going whacky the worse the front battery got.  All seeming to be caused originally by the Kessy.

 

Is the source of the problem in the Kessy unit due to water ingress?

 

Scott

[Brit6]

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...............

[Kenatic]

I wonder if a different rating of resistors would work...?  Risky I know.  But we all agree it's broken right?  In one set of pictures in this thread the resistor color code looks orange to me on my mac(note I lost my color vision years ago to an undiscovered tumor crushing the optic nerves, but it was treated a while back and now I have fantastic  color vision, but am still learning to associate names with colors) -- anyway, orange would be .33ohm.  In another picture is almost looks like there is red barred resistors (.22 ohm) AND ones with orange bars (.33 ohm).  I am waiting on parts from mouser.com and will take a look when I get the unit out.  Often the underlying color of a resistor will make the bars look different then the intended color.  The only way to know for sure is to test a known-good resistor on a ohm meter.  

 

Question: The resistors may act as fuses to protect the MOSFET rather than the other way around (or both?). If they are too low resistance that could blow the MOSFET vs the MOSFET blowing the resistors...?  I have several EEng friends; I will chat with them as soon as I get my unit opened up.

 

I had a similar thing happen on my Samsung LCD TV.  Factory resistor parts were too low resistance and the tolerance top poor.  They blew and took out a MOSFET used to turn on the TV.  An EEng online figured out the right resistor rating needed (more resistance, higher wattage too).  I replaced the resistors and MOSFET on the TV and it's been years and it still works fine.  Samsung would not cover the repairs even under warranty!  I also had a similar thing happen on a Magtag washing machine.  Poor quality resistors blew a MOSFET that operates the wax-motor driven door latch.  Again, I found a fix involving narrower tolerance resistors with a slightly different resistance rating and replaced the blown MOSFET.  Worked great ever since.

 

So maybe it's a similar situation here?  I'll let you know what I find.

 

Scott

[lewisweller]

Hi all,

My kessy was not working for entry/exit or the Dummy key. I replaced the mosfet and resistors in my kessy and works a treat now. I found only one mosfet was damaged but changed both anyway and 3 resistors which obviously was for the blown mosfet. The key is the drain ie the back of the mosfet soldered onto the pcb, this must be a solid solder sandwich or the mosfet won't work well or sometime at all. I did it 3 times to get it good. You can hear a sound like a crack when the solder is going to liquid and the pressure applied to the mosfet pushing it down with a screw driver to make the contact point for the solder to melt.

I also smeared the solder on the pcb evenly prior to trying to solder the mosfet drain on.

The kessy is under the drivers side dash panel nearest the center console, so water ingress is doubtful.

Battery drain could be many electrical circuits, there was a how to I read about connecting amp meter to battery and pulling fuses to determine the Power drain source.

Note the mosfet I had where different to the other people's that I copied the part order from, so when I opened it up and saw they where different, I had to reorder from mouser the correct ones.