Hello Curtis, hope all is well. Did you ever figure out what the issue was? I have a similar issue and was wondering if it was related.
I was replacing the driver-side wheel hub one fine day and once I was done I took the Rover for a test drive (2001 P38). Everything worked fine so I parked it and left it for the night. The next day I get in and attempt to start it and nothing. The vehicle would not attempt to crank, the dash board did not seem have any power (no messages, no Check Engine Light, No ABS or Brake Warning Lights, no messages on the screen - completely off). I would turn the Key and instead of the vehicle cranking, I would hear a faint click underneath the Passenger Seat (Not sure if this is the Becm or the Starter underneath the vehicle). I checked Battery Voltage, all was good. Tried to Jump the battery with a Battery Charger (it has a jump start setting) and nothing. Checked the Starter Relay and it seemed to work. All locks open and close so I suspect the car in not in inmobilization mode. I am able to insert and remove the key just fine.
I have not yet attempted to Jump the Starter Pins or applied voltage directly to the Starter to determine if this is the culprit, but I'll do that tonight.
1) The Dashboard does not display anything when I turn the Key. It is completely dark. However if I open the driver door, it lights up and shows info (example: key in ignition, etc). I don't see any inmobilization message and I don't recall if I saw warning/CEL lights.
2) When the vehicle was operation these past few weeks, the dash display has been acting up. It is as if had a short or a loose connection somewhere. While the car is on, driving or not, the dash would turn off and on intermittently (fuel gauge needle would work and then drop during the episode) and I would hear several rapid clicks which sounded like relays. Not sure exactly where these clicks came from or how many different places they were coming from, but I know definitely that one of clicks came from the shifter. I know there is a relay there that allows you to change the knob once the brakes are pressed. I would hear several rapid clicks there and after a while they would go away (shifter clicks and Display issue happened simultaneously); this would happen several times during the drive. Some of this clicking may also be coming from the Becm, but I'm not completely sure as this happens while I'm driving. It has happened while the vehicle is idle, but haven't been able to identify if some of these "clicks" actually come from the Becm.
3) When I purchased the car, I did not get the original Key. Every so often, the Car will enter inmobilization Mode and I will have enter the Emergency Key Access Code with the open and close sequence using the key. So far this has happened about 5 times in the last 2 years and I have sucessfully gotten it out of alarm mode, but I have found that it seldom works the first few tries and I generally end up getting it to work after several hours.
There is definitely some electrical issue causing these intermittent clicks (relays?) and the Dashboard to turn off and on. If any experts read this, any clues of where I should look? Loose wires in the BECM? Curtis suggests that his Becm may be out of sync, could this be a potential reason why I cant get my Rover to crank? All suggestions are welcome. Thank you (Luis).