Leaderboard

Hi mate. As for the check sum I think there is 2 different methods. As follows: If you have an ECU with an immobiliser, you cannot change the value at the checksum location or the car will just run for 2 seconds and cut out. What I did was change the values just above the checksum to make it match, originally the unused memory above the checksum are all 02's. As I put bigger injectors in I had reduced allot of the values which meant I only had to add the difference, therefore this only meant changing a few 8bit values. In my immobilised ecu the checksum is at location 0xEF00. The principal of the check sum is that it is simply a 16bit value that is the accumulated total of all the 8bit values before it. PM me your email and I'll send you the XDF that I have modified to calculate the checksum, its for the CP ecu which will be different but the calculation principal will be that same as long as you can locate the checksum and the range it covers. To view the XDF info go to XDF->view/edit XDF header info, click on the "checksum tab" and then click 'Edit Selected' As for the un-immobilised ECU's I've couldn't say for sure but I think you can just change the checksum value so it's simply a matter of locating it. On the AG ECU I remapped I could never locate the checksum so never bothered with it, it just gives a VAG-COM error but runs as normal.