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