Only some Japanese and SAUDI markets 850 dashboards might have all components required to use this parameter.
All other mostly has components missing for this to function.
WARNING! by default this is disabled either by value (in hex) FF or 80.
You need disassemble the dashboard fully though i personally calculate this to be more easy than later models as the whole front where are needles comes off as one piece on 850 than taking all individiually off. You need Torx T8 and T10 for the screws (need long shaft on around case T10 screws).
On PCB is missing next components you need solder in place.
When sound is output the next kind of buzz signal is produced when activated Speed Warning parameter has been reached.
And It sounds like this (this is actually up to buzzer what frequency it uses) video example.