ECU=Engine Control Unit
ECM= Engine Control Module
ECCS=Engine Computer Control System
They're not the same thing, sorry. The ECCS is the entire system consisting of multiple sensors and the engine computer. The ECU is simply the engine computer itself.
Owner of NPORA, mod for Nissan-Infiniti Forums, NissanForums.com, NissanHelp.com, AllNissans.com and VGPowered Forums
'88 Pathfinder: 6" of lift, 33x13.50 Swamper LTB's, Rancho 9000's, L&P Stage 3 steering system, K&N, Pacesetter headers and 2.5" exhaust, Lock-Right locker, 110A alty and electric fan swap, dual batteries, 700W+ worth of PIAAs, etc.