can the low pump pressure be caused by the actuator or clutch
Low pressure can be almost anything, but some of the error codes are open to misunderstanding- low pressure can mean that there wasn't enough pressure in the system to complete an operation because the pump didn't kick in at the right time, or that fluid is leaking away somewhere. Or many other things.
In simplistic terms, the system works by using the pump to create a reserve of pressure, with valves and actuators being opened electronically to "move the gear lever" or "press the clutch". Each of these operations "use up" some of the pressure, so, when it gets down to a pre-set level, the pump kicks in again to restore the pressure.
The accumulator is a metal "sphere" with a diaphragm across the middle, with gas on one side, and fluid on the other. This stores some of the pressure, so the pump runs less often.
It is possible to monitor the pressure in the system using
MultiECUScan. You should be able to see readings fluctuate between the high (pump stops) and low (pump starts) values, which reduce in steps each time a gear change is made. When no changes are made, the pressure will slowly reduce over a few minutes by itself if the actuator is in good condition. If it has an internal leak, or the accumulator diaphragm has failed, , the pressure will drop in less than a minute.
A failed accumulator will cause the pump motor to run too often, leading to pump motor failure if not caught fairly quickly. This can be identified in
MultiECUScan by the pressure reading fluctuating rapidly, and only getting one or two gearchanges between motor stop and start, rather than the usual amount (depends on model, but probably 8 or 10)