07 Volvo D-12 ECU issues

Here is my problem...
Vnl, when running with Ac on voltage drops to 13.3,when Acs off gets up to 13.9
I may shut the engine off and it won't start,then suddenly after couple minutes all is good.
Batteries, alternator checked,both fine.
Any ideas?

 

What year? Do you have a battery disconnect switch? If so, check the cables on the back for loose or scorched.

 

If ur ecm goes bad the truck will not crank at all...all you will hear is the truck trying to crank.The dashboard will show bad ecm on the screen.I just had that issue a couple months ago.When you see maintenance ecu that could mean anything.

 

Hi fellow Trucker’s first time post I have a 2005 Volvo VNM I’ve had trouble with this truck since I bought it used had 500,000 on it always seem to have power until I started having EGR problems I have deleted all the EGR‘s and had the computer flashed I still get a code 128 266 FMI3 truck takes forever to get up to 60 and I have to downshift quite often I see a lot of post with the same problems but at this point I don’t know if I’m running into fuel problems or computer problems any help would be greatly appreciated