We've had a number of issues with CAN on the Jaguars in the past. The support folks at Vex were very helpful, but in the it seemed to be issues with different versions of the Jaguars so we dropped it. FWIW, part of the issue was conformal coating on the modular connectors, but changing that did not completely resolve the issue.
This year we have to use CAN to get battery voltage from the PDB as well as communicate with the pneumatics module, and want to use it for motor control, but it seems the Talon SR's in the KOP do not have CAN, but rather the Talon SRX's do.
See here...
http://content.vexrobotics.com/vexpr...t-20140819.pdf