I suppose you could have checked for current to the pump during a drain cycle. Or somehow wire it direct to current and see if it works.

Does it stop draining throughout the cycle or just at specific points?

Did you check the coin trap?

Just buy a new one from eBay and drop it in, makes life much easier, the pump itself gets filled up with muck behind the impeller.

Tried googling the error code?
My AEG gave one which pointed to the drum motor. I guess some might just say 'error' and nothing else helpful though.

I've just connected pump straight to mains to check - though you'll need a mains lead with spade connectors on the end which is kind of a dangerous thing to have, so I couldn't possibly recommend doing that (seriously, you need to know what you're doing before playing with mains electricity - always disconnect the plug end from the mains before messing with the live bits).

Though it never has been the pump which is faulty - normally it's just a blockage somewhere. Also worth noting that error codes can be deceptive - with our old one it gave a code which was supposedly related to the door latch, but having checked that (and wired directly across the contacts to isolate it) and even gone as far as replacing the main PCB I eventually discovered that the fault can also be caused by worn motor brushes 🙄

my last washing machine used to do this with boring regularity (well; it did it twice) - both times the pump was fine; but the impeller had snapped. Frustratingly you can't buy the 20p's worth of plastic without the pump attached to it.