I'll check it, but pretty certain its the battery.
New battery is in, thanks to RACV. Old battery tested bad. Car started up fine. Set the trip computer, did the engagement learning procedure, all good, drove out of the car park, down the road to go home, checked my speed, -45kmh, checked the mirrors ... wait a sec ...
-45kmh?!

The speedo is broken now?
The needle is pointing straight down, somewhere between 0 and 240kmh.
To do that it must have turned fully clockwise, cos theres a stop just before zero it couldnt have gotten past.
Anyone know whats happened?
