Foreign cars do not often have the 'pump only' (the pump by itself with no module) option domestics often do. The individual pumps are often weirdly designed as well and not like the generic modular type pumps often used here that can interchange with some minor mod work done.
The entire fuel pump/sender outer module thing is one more of the unitized parts things I bring up as new ways the car companies turn the engineers inward to find more ways to make more expensive parts that bump up company profits, they redesign to make several parts all into bigger subassemblies that force you to have to buy several parts to get the one that commonly wears out. That process often replaces the oldschool thinking that said to mod the assembly to be better, if they can get away without doing it now they do, it sells more parts not doing it unless the government forces them too.
I have replaced pumps 'alone' like you propose and saved big $$$$$ but only on domestics, you have to have a fairly easy to change basic pump that works there without totally redesigning everything to even begin to work. The strainers commonly can be recleaned to work fine unless ethanol has ruined them and that part is always unpredictable. The last Ford pump I did involved modding the OD and length to work and the outlet changed position to have to mod up a one-off special top of module cover to work, not hard but very few will go that far. Parts were easy to make and basic pump was $35 on an entire module assembly price of $450 so it was worth it to me as I had done it on 2 cars. The pump itself will generally be junk and even more so if ethanol is part of your daily fuel, it either eats the wire insulation to short or the glue that commonly gets used to hold the permamags in place, then they come loose to grind up on rotor. I have replaced NLA strainers with other bastard shapes that fit the pump inlet, they work fine if you work out the physical fit issues and make them end up at close to tank bottom to feed pump right. That involves getting the filter just right with the level sensor float height to still have tank run to zero before running out of gas. It can be helpful to know that now usually part of the pump output is used to fill the plastic module up to keep it full so pump never runs dry even at very low tank levels. So, look at how they accomplish that, it helps to understand some of the perceived to be excess plumbing there.
When you ultimately meander about in your mind to realize that the OEMs by making that whole pump thing one part has you paying roughly $100+ just for the plastic case I just want to kick the **** out of somebody.
I would say yank the pump module connector and check for corrosion, most are clean but then there is that occasional one that did not seal at the weather seal and then water gets into it to do the same thing. Some even melt if the connector used there is substandard and getting to be a common OEM problem as they try to make things continually lighter. They then use connectors that overheat due to not being substantial enough at the cross-section of the connection itself. Ford does that all over their cars now and more of the engineering turned inward thing I spoke of above, to get more parts sales and repair throughput into the dealerships too. That means look close at pump relay socket too (part of main harness usually), think of what part will cost the most to replace, that is the one they will choose to under-design to fail early. The sockets overheat to let the relay pin not be tight in socket but you think it's fine since you are forcing multiple pins in place, the good high friction ones make you think all are OK when maybe one isn't. The socket has often distorted too due to excess temperature. I always rebend the socket contacts to be tighter when working a relay, and if not satisfied I will cut it out and cobble up my own individual wires to make sure the relay has 100% contact on all pins. My fuseboxes sometimes can be ugly inside but they are absolutely rock solid in performance, the only thing that matters.
If you go into the pump module don't be surprised to find a whopping mud layer of sediment inside, depending on your area red rust dust from gas station tanks will pack up in the pumps to shell them out and sometimes water based trash in the ethanol to make like a white gluey snot mess that is just gross. Use water to clean it, nothing else will work.
Go there, enroll for free and service manual link at the banner across top of page, drill down through the pages to get to your year and model and download the different sections. You'll need 'FL' for fuel system and any others referred to in that one, the first 2 letters in green are the other sections needed.