I don't have that manual in front of me, but I think Code -05 is an accelerator problem? The accelerator switch is not closing as the truck sees the accelerator potentiometer increase in counts. Both of them are right next to each other under the accelerator pedal. I work for Crown, but it has been a while since I worked on the older FC4000's. You can check your brake switch to see if it is stuck, but it is usually one of them. The brake switch when stuck for more than 3 seconds with the traction command given, will give a code too. Sorry, don't have that book available right now.