GM uses the term Pcm when one module acts to govern both the engine and transmission. When the build uses a separate transmission control module, the module that governs the engine is called an ecm. Generically, pcm and ecm are interchangeable.

Its way to early to condemn the pcm. If the battery is bad, the ecm will try to charge the system at a higher voltage.

 

Branding! Ford tends to use ECM (Engine Control Module) while Chrysler and GM use PCM (Powertrain Control Module). Both are the same thing by different names.

 

Cool. Thank You Primem, & Alloro. All of this has indeed been an Education, sadly I wish that it was Voluntary, instead of due to a poorly running Work Van. Again , Thank you both!