I have a 2002 HO with 241K miles.  It has been sitting for the last year or so as I haven't been able to get it running. Was driving along one day and it shut off, never to run again.  Overhead reads ccd after about 10 seconds.  No start, no wait to start light, no transfer pump.  My generic code reader doesn't indicate any codes present.

 

I have messed around with it on and off for the last year or so, trying about everything in every forum I've found.  As I'm writing this, I have every module disconnected (except overhead) and no difference.  Initially I had around 1 volt to ground on each of the bus terminals.  At the moment, it's up to about 2.5v on each terminal.  When I had PCM disconnected I had 4.3v or so on each.  The ECM is not connected.  I thought for sure when I started pulling modules it would go away, but at the moment that's not the case.

 

So, currently I have the 2.5v I'm supposed to have on ccd bus, but still get the ccd message.

 

Any thoughts or recommendations are welcome.

You need a minimum of the ECM and PCM to function. Overhead is not requirement. Remember most of the stuff starts from the PCM the ECM is a add-on to the PCM. So kind of required. Everything on J/C 7 can be ditched.