Code a6 : material handling switch installation abnormality. Other words means you need to check the switches on the lift, tilt and side shift levers. check them for proper adjustment, ohm switches out to see if they are good, check the wiring to make sure they are reaching cpu and no shorts , if wiring and switches all test good you have a bad cpu board ,hope this gets you in the right direction, 90percent of the time you will find a switch has failed