ECM does stand for engine control module but adding a "s" makes it more appropriate.
Codes should be checked on all engine modules: LH (fuel), DI (ignition - there are two), EA/CC/ISC (electronic accelerator/cruise control/idles speed control) and the BM (base module). You might also want to check the DM (diagnostic module) although it won't show a running problem that isn't shown in one of the other modules. It can tell you which other module to check.
There will often be codes thathave no bearing so be carefull.
Bosch Master, ASE Master, L1
33 years MB technician