calculate CheckSum E2Prom 25640 PCR 2.1 1.6 TDI

[Team dz]

Hi all

Topic for discussion
How to calculate CheckSum E2Prom 25640 PCR 2.1 1.6 TDI + Unlocked E2Prom Manual Without a program or tool



1-Unlocked E2Prom 25640 Manual

2- open the file

***********************************************
file is locked

0x024A :0000 0000 0000 434C 4E41 25B6 B4BE A771
0x0250 :8C7F 0000 0000 0000 0000 0000 0000 0000
***********************************************

25B6 B4BE A771 8C7F XOR FFFF FFFF FFFF FFFF = DA49 4B41 588E 7380

Replace 25B6 B4BE A771 8C7F to DA49 4B41 588E 7380
***********************************************
file is unlocked

0x024A :0000 0000 0000 434C 4E41 DA49 4B41 588E
0x0250 :7380 0000 0000 0000 0000 0000 0000 0000
***********************************************
calculate CheckSum E2Prom 25640 PCR 2.1 1.6 After adjusting the km

Km stored Ibiza FR in 0x02F4 and 0X02F8 and 0x0C9C and 0x010A2

Take 3 lines :

0x02E0 :0000 D7E0 FE00 D8E0 FE00 D9E0 FE00 7476
0X02F0 :C7B0 1200 C8B0 1200 C9B0 1200 ACEB 2700
0x0300 :4350 D680 7480 0D7F 9C77 4B76 716E C679

************************************************** ****************************************

C7B0 1200 = 00 12 B0 C7 Convert : 122490,3 km
C8B0 1200 = 00 12 B0 C8 Convert : 122490,4 km
C9B0 1200 = 00 12 B0 C9 Convert : 122490,5 km



CheckSum C7B0 1200 = CRC : D7E0
CheckSum C8B0 1200 =CRC : D8E0
CheckSum C9B0 1200 = CRC : D9E0
************************************************** ************************************************
122490 ,3 km = C7B0 1200
C7B0 = D7 E0 CRC
D7= C7+1
= D7
E0=B0+3
=E0
CRC=D7E0

//************************************************** **************************************************
If you have changed your km to 251322 km :

0x02E0 :0000 XXXX FE00 XXXX FE00 XXXX FE00 7476
0X02F0 :2659 4700 2659 4800 2659 4900 ACEB 2700
0x0300 :4350 D680 7480 0D7F 9C77 4B76 716E C679

***************

Who can understand the method of calculating the checksum Please do not hesitate to complete the explanation

For interest and learning

Team dz

Thank you .

[omarino]

Hi
Very interessting topic
Specially if adapt anthor ECU by hand
Regards


Envoyé de mon iPhone en utilisant Tapatalk

[pawel7924]

From my observation ...

pcr 2.1 vw passat 2011 1.6TDI CAYC,

mileage string 1 : cf e8 30 00 , checksum c6 f0
mileage string 2 : d0 e8 30 00 , checksum c7 f0
mileage string 3 : d1 e8 30 00 , checksum c8 f0

it was approx 320.000 km (tacho 220.000)

i found file with ... 194.000 km and copy strings with checksum
mileage string 1 : 11 a8 1d 00, checksum d3 2d
mileage string 2 : 12 a8 1d 00, checksum d4 2d
mileage string 3 : 13 a8 1d 00, checksum d5 2d

and copy this strings to my file

after change ignition ... ECU notify checksum error - but not present ... I erase it...
turn on/off ignition many times (10 or more), there is no DTC errors ...

I confirmed mileage - remove flowmeter plug...
error in ecu has mileage 220.000 that I think it was correct.

[Junkyard Dog]

Team dz solution have good cks??? Thanks for answer

[stranger345]

Team dz, are you sure that D7E0, D8E0, D9E0 are checksums? Where did you get this information from?