Originally Posted by mongo75

The ICP is Injection Control Pressure (sensor) it's located at the front of the drivers cylinder head. If you simply unplug the connector, it will go into default mode and if the ICP is indeed causing a fault of some sort, the engine should run better. The HPOP, is the heart of the engine. The High Pressure Oil Pump provides high pressure oil to the injectors via the cylinder head (internal) rails anywhere from about 550psi to 3500ish psi, where the injector intensifier piston multiplies that amount by 7, so you get 3500-21000 psi of fuel being pushed out of 7 tiny holes in your injector nozzle. As your HPOP begins to wear out, you will gradually notice a loss in power and an maybe increase in smoke when the hpop can't push fuel like it used to, or rather force the injectors to atomize fuel like they should. Hope this offers some insight to the system. It's an old system Caterpiller started some years back, but it is reliable and proven. Best thing about it is if you lose oil pressure for whatever reason, you can not run and seize the engine.