Wife's Car----This mostly occurs when she's cruising down the highway at 55-65 mph and the motor suddenly just cuts out. It always starts right back up, but it's a bit unnerving if you are rounding a curve and suddenly you need a great deal of strength to turn the wheel while restarting the car in neutral. I changed the fuel filter canister just ahead of the passenger side rear wheel and the old filter wasn't particularly dirty inside. As the fuel pumps are rather pricey, I'd like to get some ideas as to what else to check before replacing the fuel pump. Thank you, Paul, Providence, RI

 

fuel pump relay for starters

 

Agreed. It very much sounds like it is lacking enough fuel volume. Have the fuel pressure tested. The 07 model has a sensor so you can read the pressure when you are driving.

Just use sense since you don't want to be distracted while driving.

 

The only manual that I can find for this car is the Haynes (4263) Volvo V70 & S80 which is not specific to the XC70..Regarding the 07 model having a sensor allowing pressure to be read while driving ? , are you saying that I can hook my gas pressure sensor to the fuel rail and drive the car with the pressure gauge possibly taped to the windshield to view the pressure? I used this method diagnosing my 1986 Ford F150, but I'm not sure if I'm understanding you completely. Thanks, Paul, Providence, RI

 

I'm suggesting that you plug a scan tool into the OBD II port and have a helper read the fuel pressure via computer while you drive the car.

Do not connect a manual pressure gauge to the system.

 

Now I just need to know where in the car is the fuel pump relay located? It's a 2006 XC 70. Thank you, Paul

 

https://www.matthewsvolvosite.com/fo...ic.php?t=52622

 

and guess what ? , this 2006 Volvo XC 70 doesn't have that relay. This was confirmed by a Certified Volvo mechanic from Swedish Motors in Seekonk, Mass. This stalling issue seems to happen more often when hitting a bump on the highway going 55-65 mph. Any other ideas?Thanks, Paul

 

To my knowledge, the cars are virtually the same 2001 to 2007. The fuel pump needs a relay to handle the current draw. Certified or not, here's the relay.

https://www.rockauto.com/en/catalog/...ing+relay,3380

Again, I would suggest that you have someone monitor the fuel pressure while driving.

 

They are not the same from 2001 to 2007. 2006 does not have a fuel pump relay.

My guess would be an intermittent fault in the fuel pressure sensor.

 

This is right out of Alldata for the vehicle:

The fuel pump control module powers the fuel pump and regulates the output of the pump. The fuel pressure changes with the output of the pump.

The fuel pump control module is supplied with battery voltage by the fuel pump (FP) relay and is grounded in the car body. The fuel pump (FP) relay is controlled by the central electronic module (CEM) when requested by the engine control module (ECM).

The engine cannot be started if the power supply to the fuel pump control module is faulty because the fuel pump will not then be powered.

The fuel pump control module is controlled by the engine control module (ECM) via serial communication. The fuel pump control module then controls the fuel pump by transmitting a PWM voltage on the ground lead for the fuel pump. This means that the voltage drop across the pump changes, and with it the output of the fuel pump. Also see Function.

There are no diagnostics for the fuel pump control module. The engine control module (ECM) has diagnostics for fuel pressure regulation and the associated components. Also see Fuel pressure regulation, diagnostics.

The pulse width modulated (PWM) signal from the engine control module (ECM) to the fuel pump control module can be read off using VIDA.

The fuel pump control module is on the outside on the right-hand side of the fuel tank.

 

Cars with a PEM do not have a fuel pump relay.

Check the wiring diagram for an 06 (or 05). Then check an 04.

 

I suggested a long time ago to monitor the fuel pressure while driving. All of the debate over the mechanism to power the fuel pump system is somewhat moot until we can verify a fault in the fuel delivery.

 

Until it's verified that fuel pressure cuts out and then someone tells him to check or replace the relay that doesn't exist.

 

Without modern diagnostic tools, or a lot of experience, you end up shooting the parts cannon at cars and missing the point. I just diagnosed one today that supposedly needed a new throttle body. What I found was a crank sensor unplugged.

Plug it in, car runs very nice. You tell me.

 

Does the 2007 V70 have a fuel pump relay? I bought a big red one with 103 on it but cannot find where it goes. So frustrating. I also could not find a fuel pump control module in the rear. Any help?