Rawze.com: Rawze's ISX Technical Discussion and more

Hello, it has been awhile since I have been on the forum, also been awhile since I have been trucking. It is good to be back..

2012 Volvo, CM2250, 936K miles, (guru tuned at 600k).

Getting ready to hit the road in a few weeks, did a service, put the fuel filter on dry as usual. Usually cycle the key 6 times for the lift pump to fill the filter.. cycle the key, no lift pump noise.. pulled the pump and hooked it direct to a battery. Nothing, if it tap on it it will run just a bit but very weak.. so I know the pump is bad.. pulled the relay.. no voltage on pin 30 with key on..

Now the problem, I cannot for the life of me find the fuse that I hear controls voltage to the relay. I found one in the outside fuse panel that is for the NOX and it is ok..

Any ideas would be appreciated before I tear deeper into this wire harness.. does Volvo even use a fuse between the relay and the battery?

Thank you, JMBT

On the CM871's, the fuse and relay both, for the lift pump, are located in engine the wiring harness, just to the right of the ecm. Not sure about the CM2250's though.

Thanks Rawze, that is where I was looking for the fuse and also where I found the relay. So I searched and searched, found no fuse on the Volvo side.. looking back over the wiring diagram on QuickServe I saw the ECM controls the ground pin on the relay pin 85, and return signal is pin 86.. so I tested again for power on pin 30 with the other lead of my tester on the chassis.. and I have battery voltage. I have ordered the pump..

It appears Volvo did not use a fused link to the pump relay, at least not in that location as other OEM’s have. At any rate the failing pump didn’t blow the circuit.. so I should be good to go with the new pump when it gets here..

anyone know the average life expectancy of these pumps? I'm coming up on 750,000 miles on my 2012 and I'd like to be ready with a replacement on hand before it fails.

JimT, mine was original and the truck has 936K.. but I will tell you it gave no warning signs at all, worked perfectly last time I serviced the truck and primed the fuel filter.. then this time nothing..

New lift pump is painted and I will install it tomorrow when the sealing washers come in..
Current price here in southern OK, was $600, for anyone wondering