2008 XC70, loss of all electrical power

mrscullini · Post by **mrscullini** » 06 Aug 2025, 13:59

I've searched the site and the web. Seems as though things are pointing to the CEM. Here's my predicament, the patient is an ’08 XC70 with 3.2 and about 200k on it. Recently I’ve had an intermittent problem where we’ll loose all power, no interior lights, nothing. We would jiggle the positive terminal on the battery and power would return. Figured it was a battery issue. Replaced the battery the issue continued, so not the battery. I haven’t been able to restore power. Battery measures 12.6V with no motor running. When I connect the ground strap to the negative terminal and probe between the 12V bus in the A fuse panel (connected directly to the +12V) and the negative terminal I have no Voltage. If I remove the ground strap I have 12.6V. I was thinking I had a dead short in one of the circuits. Removed ease fuse individually from the panel to isolate circuits with no return of Voltage at the bus and ground strap. I then removed all fuses from each of the respective panels thinking it might be multiple circuits and no luck. I’m now thinking it is the CEM. Removed that and there is no exterior visible damage. Looking to send it to Xemodex for diagnostics. Anybody experience something similar of have any thoughts?

mrscullini · Post by **mrscullini** » 06 Aug 2025, 15:40

i think i found the issue. the fusible link on the positive lead for the battery. it looks like one these has failed.

Vova585 · Post by **Vova585** » 06 Aug 2025, 17:40

I just wanted to mention that. It is a common area. You can replace entire cable vs volvo sells "patch" kit

jf112 · Post by **jf112** » 12 Nov 2025, 10:27

I have a 2016 XC70 that experienced sudden loss of all electrical power.

I tried to start the car - for a second everything was normal; dashboard lit up..., bu then everything went dead.

I found the positive battery cable - it has two 175 amp fuses, the battery terminal, and a thin wire with a plug at the end

The part is Volvo 31473638

When i look at the two fuses, they seem fine - can the part fail in another way?

Maybe that thin wire with the plug?

Vova585 · Post by **Vova585** » 14 Nov 2025, 12:00

1. Verify your battery is good. Can place booster pack , vs other battery vs taking your battery to store to test and charge(usually advance does this for free).
2. If after verification of proper power supply, you still experiencing no power. Try to test voltage differences between center of negative post and body ground. Center of the positive post and next in line connection(or at the starter "fat" post).
3. Thin wire is a part of battery charge sensor i believe. It should not influence your situation.
4. Can take large 12v bulb(high beam 55w) and make yourslef a test light via connecting 2 wires to it. Now test negative post to starter "b"(battery) terminal- bright light=decently good positive wire. Now check from positive batery post and body/engine ground post. Bright light-likely wires a good. No bright light or dimm light(with healthy batery present )- problems with corrosion or connection on the corresponding testing side.