Mitsubishi Outlander 2011 2.2DiD ignition off dash still on

[sandsltd]

HELP !!

Had my car in for MOT and failed on steering sensor
Friend plugged his diagnostic machine in and found fault but once removed test equipment and removed the ignition key
Dash is fully illuminated with lots of warning coming up and reversing lights on.
Tried disconnecting battery but still same
and diagnostic not communicating with car now
Car starts and runs as normal but every time remove key dash fully light up still

Help please

[Deranged Rover]

Maybe take it to a garage who knows what they're doing, rather than relying on your mate, who clearly doesn't?