Canon Saddle Finisher-T2 Service Manual page 235

c. Download
The error code E503 might occur during download. It does not affect the download operation and its results.
1) Start up the Service Support Tool.
C:\ProgramFiles\Service Support Tool\bpchost.exe
2) Select the type of host machine.
F-4-56
F-4-57
Chapter 4
4-49