Thanks you for describing this method, but it's not working for my Toyota 7SM12. I think, I would need the can-key for it. 1100 H ist the setting..
The display shows for a longer time (only) the fault code C29, now the forklift will not drive in any direction anymore, but the lift is working.
Any ideas to fix it?
Thanks in advance!

rogeriwt is correct. you need to enter the system and reset parameter 25 in order for truck to release code. turn unit off then hold horn button down and power the unit on.watch the display until p appears then let go of horn button, then use the direction **** to scroll to parameter 25 then click horn button,then using the directional **** you can adjust parameter. all units have this, usually its set to 2000hrs thats why this code is really not seen very much. once its set hit horn button, power unit off and test ,hopefully this helps you out

It is a code for the service reminder. Not sure how to reset. I have never had this function turned on.