There are numerous posts using the acronym ECU meaning Engine Control Unit, or ICM meaning Ignition Control Module, (sometimes Unit & Module are interchanged). Sometimes folks refer to ICM to mean Injection Control Module. Then there is the generic use of The Brain or The Computer. I believe the hard to get to "Unit" just in front of the passenger door under the interior panel is primarily related to Fuel Injection but if that's the case, where is the "unit" (nearly the same size as the one under the panel) that controls Ignition? Then there is the tiny inch-&-and-a-half inch by 3 inch unit screwed onto the inner fender well just behind the battery which shows up when ever one Googles ICU?

I have spare units of all three of these from a 940 & suspect one of them to be the root cause of the lack of power to my new fuel pump. I've traced the current from the Yellow/Brown wire at the battery, to fuse #31, then to the FP relay which is new.

Here are numbers for all three. Which is which, what does it control and where is it? TD
Bosch # 0 280 000 563
Bosch # 0 227 400 148
Bosch # 0 227 100 124 (on L fender well?)