Help please trying to connect

[5.7senator]

Im trying to connect to my vs v8 5.7l commodore.It has a modified memcal.

I have the car off , i plug in the cable, turn the program on
i have selected the vehicle gmh-vr68vs8,i have ticked the serial 1/0.I selected the option from the left side then i hit
f3 button then all that happens is i get a long message coming up on the right side of the screen.
It says start writing frame
send $f4,$57,$01,$00,$b4
finished writing frame
wait 10ms after writing, before reading...
start reading frame
aldl frame length byte:$0
aldl frame length byte:$7
recv:$00,$55,$00
error reply frame checksum failure
finished reading frame
error no echo recieved from max232
wait 10ms after writng, before reading
start reading frame
com timeout: expecting frame header byte
aborting request due to previous error
and then it repeats the message

Thankyou if any one can help.

[5.7senator]

Also when the cable is pluged in the check engine light on the car dash is flashing.

[Blacky]

What type of interface cable are you using?
Some cables require the "Max232 Echo" setting to be checked on, some cables need it checked off.
Also, if you could copy/paste the exact text that is displayed it would be helpful.

Regards
Paul