Ok, This is not a do it yourself thing, It requires the Honda test equipment to find the cause. The most likely cause being the drivers side multiplex unit. See info from a service news article on this issue...........
Got a vehicle with power door locks that won't lock with the key less remote or the power door lock switch
but unlock with them just fine? Follow these steps to find and fix the problem:
1. Hook up the HDS, and check for B-CAN DTCs.
problem. Clear the DTC(s), then go to step 2.
2. Recheck power door lock operation using the keyless remote and the power door lock switch.
3. Do a battery cable reset by disconnecting the battery negative and positive cables and connecting
them together with a jumper wire for 15 minutes.
4. Recheck power door lock operation using the keyless remote and the power door lock switch.
MICU). Refer to page 22-77 of the '03-07 Accord S/M. (Online, enter keywords FUSE BOX, and
select Under-Dash Fuse/Relay Box Removal and Installation from the list.)