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ALH 121 pin immo delete... DIY!

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
So, being the cheap poop head that I am, I looked at the various services offered for immo deletes, and people want a hundred bucks or more to remove the immo. There's a dingus you plug into the OBD port you can buy on aliexpress that'll do it, but that's $20 or something for a single-purpose dongle. No thanks.

Reading up on ecuconnections the third option is a serial-eeprom reader, for 12 dollars on ebay. Now that's a cost I can stomach! :p

A certain friend on here was nice enough to provide an already dead victim for me to learn on. They can identify themselves if they want, heh
Good thing, too...

A 400W soldering gun is not suitable for SMD work. :eek:
I did however get pretty good at working these chips loose with a 25W iron I bought a few days later.
Well, gotta find a new 24Cxx chip since I killed the 24C04 that was on there.
Luckily I tend to save salvageable boards, this one from an old LCD monitor had a 24c16 directly below the socketed chip.

soldered on there, ignore the bridging, solder wick cleans that right up.

So, we've learned that it is very easy to destroy things. Best try and learn on something a little more disposable. Found yet another 24C16 on a board from a dell 1700 laser printer

Soldered some jumper wires to it in order to use the ZIF socket, easy enough, as pin 7 is unconnected, 1-4 are bridged and the other three are straight over. Manageable. Got it to read and it had some mentions of lexmark 1700 in the information, neat.
Now I need the info off the ECU to flash to the new salvaged chip I'd soldered on. Lucky me, I've got one fresh new $50 junkyard ECU that I'd rather not screw up. Soldered on the jumper leads and read the data, tried making sense of it, tried plugging it into software provided, nothing. Try rereading it and it reads different info every time. Try the dell printer chip again, it reads right again. So maybe there's something else in the ECU trying to power on and the little programmer can't supply enough current... So, nervously desolder the good chip from the good ecu, and solder it onto the reader board's backside

Hey, now it reads the same giberish every time!
Save the binary on the desktop and go put it into "edc15 calculator" and it recognizes it, neato bandito
write the immo-off'd file to the chip, desolder it, solder it to the ECU and put the good one away to be tested later on as it is very cold out. Doing tires tomorrow, I'll test them both then when it is in the shop.
So, back to the dead ECU, desolder the chip salvaged from the old LCD monitor, read it:

Little less interesting than the dell printer one, but w/e. neat that in both cases they don't use all the extended capacity of the 24C16 chip, everything beyond is just FF'd out, gives some hope that tossing the contents of a 24C04 onto it will work out okay.

the board on the bad ECU cleaned up real nice, I wrote the same binary to the salvaged chip, desoldered it from the reader, soldered it to the dead ECU, tossed the dead ECU in the sink, washed it for a while, threw some alcohol on it to dry it out, tossed it in the oven to try and fix it (cue rossmann repair "I rehot board it still not work" sound bite)

Well, that's it, I'll update tomorrow if it worked or not. Low hopes for the one given to me pre-killed. Moderate hopes that the junkyard one will work, as at least that one would do the "catch then die" immobilizer halted stop, whereas I didn't even try plugging in the 'dead' one.
 
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turbocharged798

Veteran Member
Joined
May 21, 2009
Location
Ellenville, NY
TDI
99.5 black ALH Jetta;09 Gasser Jetta
One trick to getting those gullwing chips off is to solder wick all the solder off the pins and then using a dental pick to pop each pin of the chip off board, very carefully. Its something that you need to do a few to get the feel.
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
Much, much easier way. Buy at chip clip!

http://www.mcumall.com/store/index.php?route=product/product&path=63&product_id=196

Before these were readily available, I used to desolder and drop into my burner. Most generations of boards had a drop of epoxy holding the chip down. Now that fun!

There's also a program floating around that will do this in boot mode for ME7.
Tried soldering wires to the chip, doesn't work at all on this ECU, might work on other ones but this one's got something drawing down one of the pins that is needed, so the ECU needs to either be powered on (didn't try it) or the chip desoldered.
 

CasaEd

Veteran Member
Joined
Mar 18, 2017
Location
Portugal
TDI
VW Passat TDi B4, VW Passat TDi B4 GL, VW Passat B3 PD AWX Conversion
I also managed to kill the chip the first time I de-soldered it with a hot air gun,(MSA15)
temperature far to high, the chip can with stand 310 deg for about 10 secs only !!
I have since found that you can remove them at 280 deg quite easily.
As for reading them whilst still attached to the ECU I've only manged that once
and I had to supply power to the ECU whilst reading and writing it, for me it's

easier to remove it, put it in the Mini Pro I have immo of the chip and re-solder it
back to the ECU.


Also you don't need to remove his chip to immo off if you have vag-commander cable (the cheap Ebay one)
It can be done with that and it's what I use for myself only
 
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Uberhare

Veteran Member
Joined
Sep 3, 2006
Location
Ontario, Canada
TDI
Too many.
Tried soldering wires to the chip, doesn't work at all on this ECU, might work on other ones but this one's got something drawing down one of the pins that is needed, so the ECU needs to either be powered on (didn't try it) or the chip desoldered.
Yes - you just have to hold the wright protect line high. Most of the burners I've seen don't do this properly in circuit. I just supply +5V directly to that pin. Works like a charm.
 

JLMurphy

Veteran Member
Joined
May 16, 2007
Location
Huntingtown, MD
TDI
2010 Golf 6MT, 2001 Golf 5MT
One trick to getting those gullwing chips off is to solder wick all the solder off the pins and then using a dental pick to pop each pin of the chip off board, very carefully. Its something that you need to do a few to get the feel.
I used to do it that way too until a buddy showed me a better method that's less likely to result in bent / broken pins.

The trick is to add solder, lots of it. You get enough on both sides of the part (bridging all pins) so that one side stays molten long enough to get the other side hot. Then the part just slides off easy as pie. Wick the excess solder off of the board / part and you're good to go.
For bigger parts I just break out my hot air gun and heat that sucker up till the part comes off.

Oh, and if you do any amount of soldering at all, especially surface mount stuff, get a decent iron. I used to use a crap Radio Shack pencil at home, that thing sucked hard. I have a nice Weller rig at work that is excellent for SMD rework. Overkill for the home gamer, but a decent digital iron can be had for less than $100.
 

turbocharged798

Veteran Member
Joined
May 21, 2009
Location
Ellenville, NY
TDI
99.5 black ALH Jetta;09 Gasser Jetta
Well the best method is to use a set of hot tweezers which will get the chip off in about 3 seconds. Problem is they cost a lot of $$


We have a JBC full iron rework station at work and its pretty incredible how easy it is to remove stuff like that. Problem is that it cost around $5K.
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
Well, the "known good" ECU worked, the one I obtained "already dead" still acts like the immo is on, but "already dead" has got the immo chip binary file from "known good" ECU so maybe they've got the vin number or something stored elsewhere in the ECU and they've got to match up. Destroyed the immo chip from "already dead" trying to desolder, so no hope of getting that file back.

my method of desoldering is to bridge the pins with solder, oull up gently and get it to move a half mm or so, cool the chip off with alcohol, do the other side, back and forth a few times until it's up high enough for solder wick to clean out one of the sides, then the other comes apart easy.

Certainly better to do it through the OBD port, but that cable has less lasting utility to me than a generic EEPROM reader does. Best method for sure, though.
 

JLMurphy

Veteran Member
Joined
May 16, 2007
Location
Huntingtown, MD
TDI
2010 Golf 6MT, 2001 Golf 5MT
Well the best method is to use a set of hot tweezers which will get the chip off in about 3 seconds. Problem is they cost a lot of $$
We have a JBC full iron rework station at work and its pretty incredible how easy it is to remove stuff like that. Problem is that it cost around $5K.
Well, sure yeah, you could always break out the big guns. :D
I've never used the tweezer type setup before, but my Weller at work has a hot air pencil that while not nearly as fast is really nice for installing / removing fiddly parts like leadless packages.
The best method is not removing the chip at all as I've already mentioned.
Agreed, if you can work on it in circuit that's the best way. Although, if you end having to solder a bunch of wires to it you still run the risk of shorting something and letting the smoke out. As you mentioned, a chip clip is the way to go if you have one. :cool:
 

hey_allen

Veteran Member
Joined
Nov 25, 2006
Location
Tacoma, WA
TDI
2000 Jetta TDI
Any pointers toward the code for the programming of these chips?


I have a nice Weller WD1, (actually, I have a few, if anyone is in the market for one...) and am likely skilled enough to pull the chip if needed, so I'm tempted to do this on a spare ECU and keep it as a backup.


That said, if a knockoff VagTacho cable could work like the suggested VagCommander to program it through the OBD port, that would be easier yet.
 

[486]

Top Post Dawg
Joined
Mar 1, 2014
Location
MN
TDI
02 golf ALH
Any pointers toward the code for the programming of these chips?
There were guides to do it I found before buying the EEPROM reader, then promptly could never find them again. One gave addresses to the bits to change, the other gave the values you wanted to change.

There's a link in the first post to the software that 'does it for you' which is a free download
 
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