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Discussion Starter · #1 · (Edited)
I gotta purge old covid gas. With other cars I've jumpered the fuel pump relay or a diagnostic connector to get the fuel pump to pump the gas out through a fuel line. I'd like to do that with the Schrader valve on the fuel rail with this car but I can't figure out how to get the fuel pump to run without running the engine. I thought maybe jumpering +12V to one of the fuel pump fuse connections may do the trick but I can't find the right wiring diagram to figure out which of the two fuse connectors or confirm if this procedure is safe. anyone done this?


2012 S60 T5 Belgium made

(edit:update)
looks like this diagram may be relevant. so there is an unidentified relay between the CEM and most of the circuits it feeds. is that supposed to be the same relay, or separate ones? on some of them it looks like the fuse for that circuit is on the positive side of the relay, and others on the negative side. why is that?

130704


(update #2:)
it looks like pin 76 in this diagram is the one to jumper +12v in order to run the fuel pump via the fuel pump control module:
130717

i don't really know what the fuel pump control module does, but i'm guessing it senses back pressure in the fuel line to regulate the activity of the fuel pump after prming it for 2 seconds when it's powered up? does anyone know if i'll fry anything by trying to jumper that pin directly to battery positive?

(update #3)
looking further at the wiring diagrams i found that there are 3 other separate unfused wires going from the Central Electronic Module directly to the Fuel pump, as well as another unfused wire to the Fuel pump Control Module, and another wire going from the ECU to the Fuel Pump Control Module. so now i'm even more confused 馃槙

(update #4)
looking at pictures of the fuel pump, there are 6 pins that are external to the tank:
130718


pins 1, 2, 4, and 6 are connected to the CEM, with 4 being the fused one that is joined to the FPCM. If i were to guess, i would guess the pins go 1-6 left to right looking at the picture but i have no way to be sure. interestingly enough, that does seem to hint at wanting +12v. worth the risk?
 

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Back in the day of the P2 fuel pump recalls, we sometimes would have to power the fuel pump to lower the fuel level to prevent gasoline spilling out onto the shop floor.

We would use a spare car battery and jumper wires connected directly to the fuel pump. Those 2 larger terminals are the power and ground to the pump motor. Without looking at a wiring diagram, I would say power those (power/ground appropriate) and have a hose attached (via schrader valve) at the fuel rail to collect the fuel.
 

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Discussion Starter · #3 ·
Back in the day of the P2 fuel pump recalls, we sometimes would have to power the fuel pump to lower the fuel level to prevent gasoline spilling out onto the shop floor.

We would use a spare car battery and jumper wires connected directly to the fuel pump. Those 2 larger terminals are the power and ground to the pump motor. Without looking at a wiring diagram, I would say power those (power/ground appropriate) and have a hose attached (via schrader valve) at the fuel rail to collect the fuel.
well, if you're taking the pump out anyway, that makes sense. i wasn't gonna do that quite yet. but the first step of getting to the fuel pump in this car is to remove the gas tank, according to the factory service manual. I plan to reuse this pump when I eventually replace the gas tank. Is that a strategy you would use if you were going to reuse the pump?

If i'm not taking the tank down, from the wiring diagrams and connector list it doesn't look like there's a way to get +12v to that 4th pin without also sending it to the fuel pump control module since it is a single pin that runs to both units from the last connector in the chain:

130750


could that harm the fpcm if i just run +12v to both those guys through the 76 pin of the CEM c2 connector?
 

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Back in the day of the P2 fuel pump recalls, we sometimes would have to power the fuel pump to lower the fuel level to prevent gasoline spilling out onto the shop floor.

We would use a spare car battery and jumper wires connected directly to the fuel pump. Those 2 larger terminals are the power and ground to the pump motor. Without looking at a wiring diagram, I would say power those (power/ground appropriate) and have a hose attached (via schrader valve) at the fuel rail to collect the fuel.
what he said, p1 and p2 is gonna be your power and ground, just give it some juice and it should start pumping out
 

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I wouldn't go from the CEM. Find the page with the fuel pump. If I remember correctly, there is a connector under the back seat (driver side) that we would use to take resistance measurements for the fuel level sensor following a TJ for inaccurate fuel gauge on P3 (seemed to always be P3 XC60). That connector might be able to power the fuel pump motor directly.

Anyway, I would try to find the easiest connector to get to that you could power the fuel pump motor directly.
 

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There won't be a terminal under the back seat because the power wire for the fuel pump comes right off of the PEM, which is mounted on top of the tank.
 

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Discussion Starter · #7 ·
There won't be a terminal under the back seat because the power wire for the fuel pump comes right off of the PEM, which is mounted on top of the tank.
aren't the PEM and FP wired in parallel? that's what it seems like according to the connector pin lists.
 

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BollWeevil,
Not having your VIN I looked up a generic 2012 S60 5 cylinder in VIDA.
According to the Engine Management wiring diagram, the power goes to one terminal of the PEM and comes out another to the Fuel Pump, so that would make the PEM and Pump in series.

Think about it, if the power supply came in parallel the PEM would not be able to control the pump speed.
 

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Discussion Starter · #9 ·
BollWeevil,
Not having your VIN I looked up a generic 2012 S60 5 cylinder in VIDA.
According to the Engine Management wiring diagram, the power goes to one terminal of the PEM and comes out another to the Fuel Pump, so that would make the PEM and Pump in series.

Think about it, if the power supply came in parallel the PEM would not be able to control the pump speed.
but look at post #3 above, which has pin 3 coming out of the +12v off F13 from the diagram post #1. pin 3 goes to both the fuel pump control module and pin 4 of the fuel pump in a 3 way connection.
 
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