Solution: C70 '06 passenger door wouldn't open
 

FYI

C70: Passenger door wouldn't unlock, not with fob, inside release handle, or metal key.

Found this solution here (3rd down) from Alpha206, who credited "oilburner":
http://www.volvoforums.org.uk/showthread.php?t=40932

Seems one stage away from turning round anticlockwise three times and spitting, but having performed the ritual, the door released... :shades_smile:

Here it is:

Try performing a reset of the UEM (Upper Electronic Module), this controls the door locks and window operation:

- Close all of the doors and bonnet.
- Key in position II engine not running.
- Hold both the driver window and passenger window switches in the driver door panel in the closed or up position for 5 to 8 seconds after the windows are closed.
- Release buttons.
- Remove the ignition key.
- Operated the remote twice. lock/unlock lock/unlock.

This will reset the UEM brain. This can correct faulty operation of the sunroof and/or erratic door lock function.

Ok, so that failed to sort out a subsequent 'door locked and can't be unlocked' event: that is, unresponsive to the fob, the metal key, or the interior release handle.

On the supposition the C70 had its computerised knickers in a twist, it seemed to me that the old-school approach might work: switch it off and back on again.

Disconnected the battery, left it 5m, reconnected, and door opens again.