You can't read the 780851AGC(A) or the flash type 78F0851AGC(A).
The 780851AGC(A) is a mask rom device, the (A) states automotive grade quality.
For mask rom devices there is a secret mode (rom test mode) to read out, but I am not aware of.
If it is a 78F0851AGC(A) not may not read-out, the on-chip flash programmer function only allows erase, program and verify, but no read-out.