Fuel pump electronic module

[charlie8]

Hello, 2005 XC 70 with 80,000 miles
Can anyone tell me what the fuel pump electronic module actually does? ...eg. control pressure, etc??
Does anyone know how to bypass this module or "jump" the connections to bypass it to see if it is the source of my no fuel problem.
Won't start and no fuel pressure in the rail. How can I tell if the in tank fuel pump is working or not??
Thanks

[Willy]

I don't know what the module does in a Volvo, but I know that in (some?) current day vehicles,
due to emission regulations, the fuel pump is not always powered with the full voltage in order
to limit fuel flowing back to the tank. The module will apply a voltage to the pump in accordance
to the required fuel under any given regime.
This is the case in my BMW (motorcycle that is :o). This fuel pump module is known to fail,
a temporary solution is to bypass it and power the fuel pump with 12V.
This will create more fuel to flow back to the tank, but it will do no harm.
If the same method is used in your car, you could try to power the fuel pump directly and see
if the car will then drive as it should.
But, as I wrote, I am not sure what the fuel pump module in the XC does.
Willy

[charlie8]

Hi Willy,

Thanks! How can I bypass the module?? Does anyone know which connectors to "jump" to bypass this and get the fuel pump working??

[Willy]

Item 4/83 of the drawing is the fuel pump module, item 6/33 is the fuel pump itself.
Data wiring is surrounded by a figure 8.
The module (point 4 and 5) transmits commands to the pump (point 1 and 2).
I think that that points A and B of the fuel pump are the power connections,
but it is possible that the fuel pump won't run without a command from the module.
Not that it will help, but I compared the MY2005 system with the previous one
and until 2004 the fuel pump was powered directly, always running at full speed.
Willy

6477

[charlie8]

Hi Willy.Thanks. I don't have any power going to the plug on the PEM with the ignition on. There are 5 wires going to the PEM and I thought one of them would have been 12volts to power it and try to jump it to see if the fuel pump would come on.
Do you know where the PEM gets it's power from??

[Willy]

The drawings show the fuse (No. 21, item 4/83) and the ground connection.
Unfortunately the schematics don't contain connectors or connector layout drawings.
Willy

6478
6479

[charlie8]

Hi Willy,
The drawing doesn't show the power source? I'm thinking there would be power going to the PEM with the key on vehicle not running at one of the connections but I'm not showing any voltage.
Do you know where the PEM power comes from.
If I turn the key on engine not running, would I be able to hear the fuel pump running in the tank??

[Willy]

I can't help you any further concerning the power source, sorry.
I am also not sure what happens when you turn on the ignition in a MY2005.
Until MY2004, the fuel pump is activated for a short period to bring the fuel rail under pressure.
The pump will start running again when the engine is crancked.
You would not hear a continuous flow of fuel back to the tank.
Perhaps owners of MY2005 on models can provide more specific info.
Willy

[volvospeed70]

Hi Willy,
The drawing doesn't show the power source? I'm thinking there would be power going to the PEM with the key on vehicle not running at one of the connections but I'm not showing any voltage.
Do you know where the PEM power comes from.
If I turn the key on engine not running, would I be able to hear the fuel pump running in the tank??

On My MY2005 XC70 the fuel pump primes for about 2 secs when i first turn the key.

You should have voltage at the fuel pump for a few secs when you first turn the key over.

[mopar2ya]

the pem controls the speed (rpm) of the pump. which controls the pressure to the injectors depending on the engine load, looking at the wiring, when you turn the key to on, there is power on the relays. when you turn the key towards start the ECM grounds the PEm and the pump runs, I know of no way to jump the PEM, I would remove the filter by the right rear tire and see if the pumps works, you might have a clogged filter, if no fuel, you could jump the pump with another battery , remove the rear seat bottoms,both sides,on the rightside rear door down near the door molding you'll see the elect wire connections, the two to the rightside ,one with three wires is the pump and the other is the gage, two wires on the gage, the gage wires is easy to check, with the key on, unplug the fuel gage wires and the gage should stop reading, if you jump the pump wires and the pump,if it don't come on, go to the drives side and remove the cover plate in the floor and under that cover is where the wires come into the tank and go to the other side to the pump, open the tank cover and look at the connection to the rightside, one wire is black that supplies powder to the pump, that connection will sometimes get hot and melt, remove the slideon connector and check if its melted,have a meter with you, if it is melted and you have no power on the inside wire, that will be your trouble, clean that connection or replace that melted cover and get power coming into the tank and to your pump,check and see if the pump works,if not your pump will be shot,and needing to be replaced,

[jenkinskg]

My PEM went for the second time, good thing I bought replacement from erie VOlvo lifetime warranty
Would love to know pin out to verify myself, I will ohm out connection to pump tonight