The 2004 V70R had error codes for REM-4A33 which VIDA says, "Fuel level sensor Signal too high/Signal missing" and ECM-4050, "Fuel level sensor - Signal too low." These codes were persistent and would come back immediately after clearing with the next ignition key-on cycle. First I inspected the pump module wiring harnesses for any damage and inside the electrical connectors for corrosion.
I opened the passenger side of the fuel tank first (after a half hour of vacuuming and cleaning dirt and junk to keep it all from falling into the fuel tank):
FCP and IPD both offer an aftermarket left fuel tank sender but the aftermarket part has bad reviews for leaking out the electrical contact pins on FCP:
https://www.ipdusa.com/products/114385/ ... s=988,1224
https://www.fcpeuro.com/products/volvo- ... n-30645854
The fuel height sensor looked to be identical between the left module without an external harness and the left module with the external harness. I went to a couple local Detroit pick-n-pull junkyards to try to get a replacement part because the left side part isn't available by itself and the right fuel height sensor is $216 from Volvo and $67 from Bosch.
All the junkyard P2 Volvos I looked at had the no-harness left modules. I opened one and was able to remove the fuel height gauge sub-assembly without much difficulty by unplugging the electrical connector from the bottom of the flange, sliding the float arm off, and then unclipping two plastic tabs while sliding the part out of a plastic slot.