Issue: While using KT200 ECU Programmer on a Seat EDC17C74, the reading process is 100% OK, but the writing process stuck in 87%, resulting in a non-starting car.

Here’s an insight into the Seat EDC17C74 ECU:

The following image shows the cable connection:

KT200 reads Seat EDC17C74 ECU data 100% OK:

However, KT200 write Seat EDC17C74 not OK, stuck in 87%:

As a result, Seat fails to start:

How to fix:
The solution is relatively straightforward. The primary culprits are usually an incorrect file or a faulty checksum. If you write a bad file, the tool can only write it file it is told to write, just write Ori back to ecu. Write the ORI file to the car, when it runs you will then see that the file is bad.

Finally Solved by doing these:
1.Correct checksum manually (using winols or Lsuite or Davinci).
2.13V power supply

Alright, KT200 Seat EDC17C74 writing failure is fixed and the car can start.