Other 70 Problem: Fuel Pump Fuse Blowing Constantly

[Brendan W]

Originally Posted by RWD

When I swapped the pump tonight I noticed that the left hand side of the tank with the sender in is at a higher level than the pump side.

Maybe there is something wrong with the in tank transfer plumbing. This might starve the delivery pump.

[RWD]

I have a fuel filter ready to fit. When I swapped the pump it was the complete unit, I had to take out the sender and feed the pickup and wiring through.

Thanks everyone, I'll keep you posted

[KBB]

Your problem will have nothing to do with a "bad earth", a poor earth prevents current from flowing in a circuit. When a fuse blows you are looking for a short to ground which will be before the electrical load. A power feed which touches ground before the load component has a circuit with very low resistance which means high current flow being more than your 15 amp fuse can handle.

The fault could be between the CEM and the pump control module or the control module and the pump. The pump control module receives a power feed at key on via relay 2/23 in the CEM, the relay receives a permanent live feed via fuse 33.

Remove the relay and disconnect the pump module connector. With a test connect a test light across the relay bed pins 3 & 1. If the light is lit up you have a short to ground between the CEM and the control module. Follow the harness and flex it every inch along its length from CEM to module. At the point where the light goes out you have located the short to ground. If you can confirm this section of the circuit I will give guidance on locating a short between control module and the pump as a slightly different approach is needed.

[RWD]

Thank you very much KBB I shall have a look tonight when I get in from work

[Chris_Rogers]

You may find this link helpful:

http://www.volvowiringdiagrams.com/?dir=

[RWD]

Right, done a bit more digging on my non-start issue. I now have a VIDA DICE units thanks to a fellow forum member, all running and installed on an old Windows 7 laptop.

Plugged it in last night, ran the diagnostics and got this DTC.
ECM-2120 Fuel pump control module - Signal too low

This relates to the Pump Electronic Module that many of you have suggested and is borne out by a lot of research via the forums and the internet.

I changed the fuel filter as it needed doing anyway, whilst I was under the car I had a look at the PEM and superficially it looked OK.

I popped it off as it just slides into a bracket under the car, the terminals looked OK on the block connector, but given what I've read I decided to open it up. The PEM has a plastic housing with a rubber seal and a heatsink. The cover pops off if you take a little care, it is not a sealed unit.

This is what I found inside, accompanied by a whiff of fried electrical components.
Methinks I have found the culprit!




I'm now on the hunt for a replacement.

Thanks for the help everyone