Hi,
Just back from a 16 day trip across Europe, but on about 5 occasions, the following all went to Zero.
Speedometer
Rev counter
Coolant Temp
Fuel Gauge
On most occasions they returned to normal almost immediately, but on one occasion did not come back for a few minutes. The engine was fine. On 2 occasions the fault occurred while on the Motorway and it didn't occur while driving through a Downpour.
Mark, back to your original post and just another thought perhaps to consider....
There is another reason why a CAN may temporarily drop out as yours did other than a suspected faulty connection. Another possible reason is from radiated electrical noise or spikes. Noise can disrupt the comms causing data loss and symptoms like you experienced. Those twisted pair network wires will only offers partial protection to interference, in an ideal world they would be fully screened. By any chance have you done any electrical mods to your car lately? Run any power cables near to the CAN wires? That pair of joined red and black wires in your last pic, are they original? I have a dim recollection from another post that at one point you were experimenting with drawing air out of the cabin through the heater matrix with a cheapy electric fan?