It can be a PITA. The information Ford used in-house...or what might be in a printed manual...is not mainstream.

I've never seen anyone differentiate between a 'pcm' and 'ecm'....same thing...refers to the engines computer. The main difference only comes in that later vehicles used the computer to shift the tranny where early ones did not. That may be the use for the change in term...but regardless...they're interchangeable amongst the general public. PCM and ECM are refering to the vehicles engine management computer. Regardless of if that computer shifts the transmission or not, it's still an engine management computer. It's not a totally different piece of equipment.

I'd still like to know what they really are refering to when they say 'emissions module'. Our trucks don't have that...and if they do...than they're refering to something other than a computer box such as the ECM and that is just confusing.



BTW, there are better ways to check for power at the coil! Use a test light or voltmeter! Voltage spikes in an EFI system are your enemy!