Work.
Plug in equipment to test jig.
No response.
Swap cable for known good one.
No response.
Swap interface for known good one.
No response.
Swap laptop for known good one (EDIT: after a FUCKLOAD of checking and testing communication settings, parity, baud rate, bit timing, mask settings, protocol parameters...).
No response.
Check fuses on test jig.
Not blown.
Check interface for short circuits and open circuits.
No problem.
Check interface has control unit (sometimes they get 'borrowed')
Control unit present.
Swap control unit for known good unit.
No response.
Ask colleague for help.

Colleague looks at the screen for a moment, then turns it from Channel 2 back to Channel 1.

It Works. Channel 2 is plugged into thin air. Channel 1 is plugged into the test jig.

!"£$%^&*(!!!!!!!

Still, not bad as the bloke who did all of the above on a prototype car and complained he couldn't connect to the Automatic Transmission Control Module. It was a manual car.
( Rotating Wobbly Hat That's not a banana. THIS is a banana., Thu 21 Mar 2013, 18:17, Reply)