The theory is you put a PEM-controlled pump into your older car that does not have a PEM. ECM tells the PEM how much load is required for the pump, PEM adjusts its PWM duty cycle, the pump develops fuel pressure accordingly. When PWM line is connected to constant +12V, the pump thinks 100% load is ...

Nothing in the diagram but I figured it out.
A previous owner replaced the fuel line from the pump to the filter. When they did, they eliminated the T back to the pump return port.
I added a T back to the return port and now have correct fuel pressure

replacing the fuel pump on a 2002 S60 with a plastic tank. Found that the return line was broken off whatever it is supposed to be attached to. Dropped the tank and can't find anything that looks like an attachment point. Anyone know what the return line is supposed to attach to?

Anyone know where the fuel pump return line connects to on a 2002 S60 2.4?

I’m having trouble with a new fuel pump in my 2002 s60. Anyone know how fuel pressure is controlled in models with no PEM?

As I try to understand the high fuel pressure - wouldn't fuel trim be high negative to compensate for high fuel pressure?
My short and long term fuel trim are both close to zero.

With no feedback to the ECM, there has to be some mechanical means of controlling fuel pressure.

No PEM

volvo part number is 30761743
bosch PN is 69746
say it is correct up to chassis 234999
mine is 121587

Replaced the whole assembly. I’ve tried a Bosch, Delphi and now a volvo pump with the same results