P0340 and U1000 error codes; car idles, jerks in reverse gear too.

Question

Takes a while to kick
Jerks when I engage the gears especially the reverse gear
On the road it idles and takes a while to pick up speed
Sometimes. It just loses power and slumps
I've changed oil, fuel pump, kickstarter, fan belts but no improvement.
Diagnosis says CAMshaft position sensor (p0340), CAN Communication malfunction (u1000), I've changed the sensor but problem still remains.

Please where is the CAN Comm module behind the dashboard? My mechanics have no idea what's going on.

Please help!