2001 S60 no comms with EC, TCM or ETM after dead battery

[Snazzyfreak]

My 2001 S60 T5 battery was drained low enough to keep it from starting (but not totally dead) when the key was left on. I connected a jumper pack and was able to get it to crank, but it wouldn't start. I charged the battery completely, then tried it again, with the same result. Hooked up VIDA and I get CEM codes for no communication with the ECM, TCM and ETM. Also all three modules show no response in VIDA. Obviously, this is why it won't start. My question is, could the weak battery have lead to this, or is this likely coincidental? I'm pulling up wiring diagrams, and will probably start with the grounds, but it's nagging at me that the car was running fine before the battery drained. Anyone run into anything similar before?

Thanks,

[jonesg]

disconnect the battery for 10 minutes. Make sure it is fully charged.

and do a soft reboot......re-connect battery terminals with key in pos II.
allow a few minutes to boot all the modules, then turn it off, wait for everything to shut down and try again.