There are over a dozen places online that say they will rebuild your ECM like AES provides ECU ECM TCM PCM BCM Control Modules Automotive Electionic Solutions Main and ECU/ECM/TCM/BCM/ICM Rebuilding Service and Auto Computer Systems - quality auto ecu, tcu, & ebcm units,engine control units/modules/computers(ECU,ECM,ECC) & transmission control units(TCU,TCM,TCC to name a few. They say they can rebuild it for about $400. Has anyone tried that? It would sure save the cost and hassle of dealer key reprogramming if the original code was retained.
Anyone had a Kessy module rebuilt?
atikovi
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411 Posts
Ordered the following components from West Florida Components. Good people. Only three of my resistors are bad but extras can't hurt. $6.22 shipped.
1/4W 0.22 ohm Mini-Melf Resistor Beyschlag MMA0204-50AL0R22J - 6
IRFZ24NS FZ24NS HEXFET Power MOSFET International Rectifier - 2
To get some clarity, I've had a new KESSY installed. The KESSY I'm rebuilding was in the car prior to the replacement. So, it should still be matched to the car and keys since nothing else has changed. Am I correct in this assumption?
1/4W 0.22 ohm Mini-Melf Resistor Beyschlag MMA0204-50AL0R22J - 6
IRFZ24NS FZ24NS HEXFET Power MOSFET International Rectifier - 2
To get some clarity, I've had a new KESSY installed. The KESSY I'm rebuilding was in the car prior to the replacement. So, it should still be matched to the car and keys since nothing else has changed. Am I correct in this assumption?
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1,569 Posts
Unless being without power caused it to lose all its memory. It happens to all of us as we get older! Is there a battery on the board to hold the electronic memory? If not, the only other way is to have a memory device installed (bubble memory or equivalent) that requires no power to retain 'bits'.
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411 Posts
It must have EEPROM on board. Otherwise if the battery went dead the Touareg would be rendered inoperable. That doesn't seem to be the case as I've disconnected the battery on mine for several days with no ill effects. Should have the answer in a couple of weeks when I try it.
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582 Posts
Hi All,
With help from Bobby78 I managed to spend some valuable time re-visiting my Kessy failure for the third time.
The Kessy module is easy to access and pull apart, my unit had 2 FETS part No. IFRZ24N faulty.
To measure the FET, use the following guidelines to determine if they are faulty.
They must first be removed from the PCB.
Before removing the FETS, I advise you remove the 2 large 6u8 caps, big blue blocks. Use a soldering iron and a fine nose pliers to lift the 2 legs from the solder pad. Then you need a fair amount of heat to remove the FET by heating the heats ink tab, eventually the FET will lift away, but make sure the G and S leads are desoldered from their respective pads.
By removing the 2 big blue caps, it is much easier to get to the FETS, also be careful not to damage the very small SMD resistors, easy to do. Take note of the value before you start, if one fails, you know the value at least.
Once both FETS are removed check both against each other, see below.
1) Use Digital Multimeter in diode test position
2) Holding red lead on Source
3) Put put black lead on Drain, you should read between 0.5 to 0.8 volt drop.
4) leave the red lead on S, now put the black lead on Gate, you should read open circuit. If not, the Gate is leaky, thus the device is not fit for purpose.
5) Now up the red led on Source and black on Gate, if this reads a low value similar to step 4, then the Gate is leaky in both directions.
When FETS are removed, clean tinned area and ensure the FET Drain heats ink pad is properly tinned and legs are bent to refit.
Use a small amount of flux and heat the FET back into place with a fairly hot tip say 400 degrees C, not to long, but it will take time to solder it into place due to the surface area, don't worry to much the FETS are pretty tough. They just don't like static.
Once both FETS are into place, check solder quality and make sure the FET tabs are properly soldered to the copper pad, this helps dissipate heat.
Clean flux away and re-install blue caps. Also double check the small 0402 resistors around the Gate and Source leads.
Check solder all over before closing Kessy box, re-install. You must put key into ignition, start engine, this ensures code synchronization happens between Kessy and your Key.
By the way, all my other surface mount components were 100% intact. It appears the FET Gate may have been zapped, via static, or a pulse or EMC burst, although the Gate is protected, the Kessy module could be re-engineered to provide a bit more Gate protection. Hopefully this should work from now on.
Thanks to Bobby78 for keeping the pressure on me to fix my unit.
Kessy module $865 + tax, 2 FETS $8.00 and half a day, fixed at last.
I have some pictures I will post later.
If there is any clarification required, drop me a reply, any good technician or a local Amateur Radio Guy you know who does electronics can fix this, but must have some basic tools.
Do not attempt this yourself if you are not equipped, you can destroy it unit and surrounding components.
Regards
Gerald
With help from Bobby78 I managed to spend some valuable time re-visiting my Kessy failure for the third time.
The Kessy module is easy to access and pull apart, my unit had 2 FETS part No. IFRZ24N faulty.
To measure the FET, use the following guidelines to determine if they are faulty.
They must first be removed from the PCB.
Before removing the FETS, I advise you remove the 2 large 6u8 caps, big blue blocks. Use a soldering iron and a fine nose pliers to lift the 2 legs from the solder pad. Then you need a fair amount of heat to remove the FET by heating the heats ink tab, eventually the FET will lift away, but make sure the G and S leads are desoldered from their respective pads.
By removing the 2 big blue caps, it is much easier to get to the FETS, also be careful not to damage the very small SMD resistors, easy to do. Take note of the value before you start, if one fails, you know the value at least.
Once both FETS are removed check both against each other, see below.
1) Use Digital Multimeter in diode test position
2) Holding red lead on Source
3) Put put black lead on Drain, you should read between 0.5 to 0.8 volt drop.
4) leave the red lead on S, now put the black lead on Gate, you should read open circuit. If not, the Gate is leaky, thus the device is not fit for purpose.
5) Now up the red led on Source and black on Gate, if this reads a low value similar to step 4, then the Gate is leaky in both directions.
When FETS are removed, clean tinned area and ensure the FET Drain heats ink pad is properly tinned and legs are bent to refit.
Use a small amount of flux and heat the FET back into place with a fairly hot tip say 400 degrees C, not to long, but it will take time to solder it into place due to the surface area, don't worry to much the FETS are pretty tough. They just don't like static.
Once both FETS are into place, check solder quality and make sure the FET tabs are properly soldered to the copper pad, this helps dissipate heat.
Clean flux away and re-install blue caps. Also double check the small 0402 resistors around the Gate and Source leads.
Check solder all over before closing Kessy box, re-install. You must put key into ignition, start engine, this ensures code synchronization happens between Kessy and your Key.
By the way, all my other surface mount components were 100% intact. It appears the FET Gate may have been zapped, via static, or a pulse or EMC burst, although the Gate is protected, the Kessy module could be re-engineered to provide a bit more Gate protection. Hopefully this should work from now on.
Thanks to Bobby78 for keeping the pressure on me to fix my unit.
Kessy module $865 + tax, 2 FETS $8.00 and half a day, fixed at last.
I have some pictures I will post later.
If there is any clarification required, drop me a reply, any good technician or a local Amateur Radio Guy you know who does electronics can fix this, but must have some basic tools.
Do not attempt this yourself if you are not equipped, you can destroy it unit and surrounding components.
Regards
Gerald
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158 Posts
Great write up. Can't wait for the pictures.
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582 Posts
Hi All,
Added photos. Happy to report the Kessy stayed intact all weekend.
Regards
Gerald
Added photos. Happy to report the Kessy stayed intact all weekend.
Regards
Gerald
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411 Posts
Took the FETS off, one tested bad. Replaced both. Replaced all 6 .22 ohm resistors. The old tested OK but replaced them anyway. So it appears the only problem with my KESSY was one bad MOSFET. The behavior I was experiencing was that the door handles wouldn't operate. I'll update once I install and test.
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158 Posts
What is the best soldering iron to use for this?
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582 Posts
You will need a soldering iron with changeable tips. Large spade for removing FET from PCB, smaller tip to remove Gate and Source. I also advise you remove the capacitors as shown in my PDF file.
Use an Iron that can go to 400 degrees C, this is only for removing/soldering Drain/tab back onto the PCB.
The good news is, Kessy and door entry and button locking still works well.
At one stage I thought it may have been excessive RF from HF / UHF radio, I have been transmitting 100 watts on HF and 50 watts on UHF all week and entry system stayed intact.
I cannot explain how both FETS could actually go leaky at the Gate.
Let's see what happens 6 months on.
Regards
Gerald
Use an Iron that can go to 400 degrees C, this is only for removing/soldering Drain/tab back onto the PCB.
The good news is, Kessy and door entry and button locking still works well.
At one stage I thought it may have been excessive RF from HF / UHF radio, I have been transmitting 100 watts on HF and 50 watts on UHF all week and entry system stayed intact.
I cannot explain how both FETS could actually go leaky at the Gate.
Let's see what happens 6 months on.
Regards
Gerald
Joined
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411 Posts
Put my rebuilt KESSY back in the car yesterday and immediately am greeted in the MFI with "Immobilizer Active". Then it shuts down. Put the other KESSY back in and everything is back to normal. So it seems the dealer did something to my old KESSY or the car to render the swap impossible. I'll be hanging on to it as a spare.
hi members
i have touareg with maybe same problem because in kessy i have one antenna in rear bumper fault but mine when insite key in the switch you can hear steering lock release steering when start car nothing apear on dash no power on and starter very quiert but fun thinks remote work fine lock and unlock for me i dont know if power comes from kessy if anybody has kessy pinout to relays
any ideal brothers
regards
i have touareg with maybe same problem because in kessy i have one antenna in rear bumper fault but mine when insite key in the switch you can hear steering lock release steering when start car nothing apear on dash no power on and starter very quiert but fun thinks remote work fine lock and unlock for me i dont know if power comes from kessy if anybody has kessy pinout to relays
any ideal brothers
regards
Joined
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34 Posts
Thank you so much for this thread. For the past week I've been having Kessy module issues. Replaced the 2 MOSFETs on the circuit board as per bkm, so far so good, all the doors open and lock. Crossing fingers for my battery to hold charge.....
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34 Posts
This fix really works, my battery is holding charge now....
As common as this issue is, this thread should be a sticky....
As common as this issue is, this thread should be a sticky....
My FETs came in today, I checked the old ones and found 29 ohms of resistance between the Gate and Source. I'm sure this was causing my dead battery issue (i'll know in the morning). I need to take the Kessy back out to check two resistors, I'll do that tomorrow as well.
Jumped in the Treg this morning turned the key and she started right up. This would've been a "dead battery morning" for sure as it was 26 degrees and I was in a hurry. Also when I exited the Treg and hit the button on the door It worked! Best $1 repair I can think of.
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