First up you should get VCDS/vagcom and scan for fault codes, and get a blue kkl flashing lead off ebay.

Physically swapping the ECU out is pretty simple, mk4 golf platform cars usually have a clip in ecu cage, just pop the clip with a screwdriver. A4/A6 sometimes have an ECU cage with security screws, which you have to drill out before you can get the little ECU plug off.

However, assuming your new ECU has an immobiliser (most european ones do), you will need to defeat that before your car will run for more than a second or so. Have a read of the threads in this section, theres lots of info on defeating immobilisers.

Once you have got the ecu in the car, if it is imobilised, use argdubs tool to read the eeprom from the ECU (where the immobiliser settings are stored) and either get the hex editor out, or use my tool to turn the immo off (assuming its an immo3, I havent got round to supporting immo2 yet). To write the eeprom back, you need to put the ecu into boot mode, and use argdubs tool again

It's really easy to tell immo 2 and immo 3 apart when you look at the hex dump, immo2 doesn't store the vin or immo Id. Easiest way to test is to read the EEPROM using argdub's tool and parse it with mine, if 95040tool reports a vin of all x's and broken checksum, then it's immo2, if it reports the vin, it's immo3. (If it's immo2, ignore the bit about the broken checksum, I don't support immo2 yet, so you'll have to edit immo by hand).

You can read the eeprom over odb, but to write it, the ecu needs to be in bootmode, which means you have to take the lid off the ecu and ground a pin on one of the chips before you power up the ecu. Sounds scary, isn't. Might be worth taking a look at my 1.8t bench flashing thread.

> Thank you for your help so far its been brilliant! Now can I have a quick round down of what I need to do please I've looked at the posts you have suggested but be good to know exactly what I need to do in what order!


No worries. I'm on my mac so cant run any of this software today, so I'm doing this by memory (you'll have to actually check the threads if this is wrong).


> Would you recommend bench flashing it or doing it in the car?

I generally bench flash as its a lot easier to put into boot mode, if you have access to a bench harness I would use it.


> With argdub's tool what are the step to read the ecu and dump it to file? do I need to install special drivers?

I use one of these cables http://www.ebay.co.uk/itm/88G-USB-ODB2-Diagnostic-Cable-409-1-OBD2-II-Lead-Win-XP-Vista-FR232RL-Chipset-/230994275228?ssPageName=ADME:L:OU:GB:3160 using the most recent drivers from the manufacturers website, with virtual comport set to com 1. I think these are the drivers I am using, http://www.ftdichip.com/Drivers/VCP.htm might be using the D2xx drivers - the info is on this site somewhere!

I use the tool like this to read:

me7_95040 --OBD -r -p 1 eepromdump.bin

but you should check the syntax for the version of the tool you are using, I think mine is the older version.


> Once I have the file dumped What is the process with your tool to immo off the dump?

First do:
95040tool eepromdump.bin

This will print a bunch of information, if your ecu is IMMO3 then it will show the VIN, Immo ID and report that the checksum is correct (if it shows the VIN and Immo ID and the checksum is incorrect, post up your bin as its likely the read failed somehow). If your ecu is IMMO2 then it will show all XXXX's for the VIN - if this happens DO NOT USE MY TOOL, as it will just screw the bin file up...I really need to find the time to add immo2 support lol.

If yours is an immo3 ecu, use:

95040tool --in eepromdump.bin --immo off --out eepromdump_off.bin

If its an immo2, then you need to get a hex editor (I use winhex, there are many others) and edit the eeprom immo bytes and the appropriate checksum bytes, as described in this thread: http://nefariousmotorsports.com/forum/index.php?topic=2973.0title=

> Then once the dump is Immo off how do I flash it back with argdub's tool? and the chip that need to be ground which one is this?

Bootmode info is here, http://www.nefariousmotorsports.com/wiki/index.php/ECU_Boot_Mode or have a search for your type of ECU and bootmode, on some ECUs the orientation of the chip is different. I earth 1.8t ecus for ~6s and they seem to go reliably into boot mode. Syntax for the tool is something like:
me7_95040 --bootmode -w -p 1 eepromdump_off.bin

> Sorry for so many questions but if I could have a run down of exactly what i need to do so I can't muck it up that would be amazing!

No worries, I was in exactly the same situation a couple of months back. Best bet is to go have a read

Thanks for this detail explanation for dummies!!!
I was about to give up nefmoto. been reading for almost weeks with no luck. info is all over and in many ocassions outdated. not everybody is a computer wizard and people dont like to teach. I learn alot from this one post.