Can someone tell me where to find information on "VEH PARAM OVERLIMIT" displayed after shutdown on CAD's lower edge.
A number of different explanations has already been offered, but I think you really have to distinguish between the various messages.
When the "VEH PARAM OVERLIMIT" is displayed on the top VEMD screen it is due to the fact that the Flight Report occupies the lower VEMD screen.
Think about it;
The situation is right after engine shut down.
Right before the Flight Report appears you have engine oil pressure low and red underlines flashing on the lower VEMD screen.
When the Flight Report appears on the lower screen this information cannot be shown anywhere.
So what the "VEH PARAM OVERLIMIT" is telling you is that some parameters are presently out of limit , that is engine and MGB oil pressure low.
The idea of the system is that you should always get an indication that there is something wrong.
The same would happen if you are shown the System Status page while having low oil pressure.
In fact, try this; next time when you are done with the Flight Report press Reset to remove it. Then press Scroll to see the System status and "VEH PARAM OVERLIMIT" will pop up again.
If you on the other hand are shown “OVER LIMIT DETECTED” or “FAILURE DETECTED” it is another story and you should consult the maintenance page for details.
RD