2001 S80 Odd computer problem

[BradF80]

Hello all,
Just wondering if any of you have come across this situation:

I have a 2001 S80 T6 . The car won't start and won't communicate with the engine computer (it's a new cloned computer but I have tried the original computer as well).

However, if I disconnect the battery and reconnect with key in position 2 as required; The car will start up and communication is perfect. Once I turn the key to the off position then try to start the car the communication ceases. If I disconnect and reconnect the battery it will start right up again until I turn the key off. I've never seen this in all my years of working on cars at dealerships etc. lol

If anyone has some insight I would greatly appreciate it, if not and I find the resolution I'll be sure to post it on here so someone can search for it.

I posted this on a few other volvo sites just fishing for a response hopefully.

[doublebug]

I think the culprit is CEM (Central Electronic Module).

[BradF80]

My first thought was that too. But based on the wiring diagrams, the PCM (Powertrain Control Module) doesn't not go through the CEM at all whatsoever. The engine module itself triggers the relay to give itself power. The CAN communication via the DLC (data link connecter) is straight into the PCM.

Unless the CEM somehow has to send signal to the PCM to tell it to give itself power. Which would not surprise me at this point. Someone let a 6 year old design their CAN network when it came to this model year car...lol

The funny thing is, I didn't have this problem when I sent the PCM off to be cloned, the car had another issue with the PCM sending out too much reference voltage to all the components in the car. But the car still started up every time no questions asked. If I put the old PCM back into the car I have the same issue though. So something happened in the few days the car was without power while the PCM was being cloned....bah