Can the bosch maxx wfl 2860 wash with only a cold water supply?

check door inter lock

Yes but there are different colour choices

A leaking internal hose.

pressure chamber blocked with soap depists scale etc will need removing for service and cleaning partial strip down required.

The diagnostics are finding a proble. Usually a time out on the fill or empty. Check water supply is clear and that the drain filter is clean

The timer sticks at one place.
Quite a common problem. The least common is the actual failure of the timer itself. It is much more commonly caused by the failure of the heater, water valve, pump, a broken wire or even a blockage in the pressure system or waste system.

unfortunately no there is no way you can alter the way the max defaults as it is programmed into the module

I fixed a y joint to the cold water outlet and fed ito both hot and cold on the machine

tks

Sam

connect at random. put on a rinse cycle. if cold water comes in then pipes are correct. if hot water comes in then pipes are wrong way round and just swap them

Make sure both hot and cold water are turned on. If that is ok you may have a faulty control board.