External links 
For me the external links looked very much like advertisement because of all the buy options on this websites, so I removed them. 

The text for the ecutesting for example says as you can see below testing & technical information but I could only find price lists and repairing options with telephone numbers of the garage at the first glance. Also www.qualitycustomparts.com doesn't sound like a link where you can get information about ECUs in general. A bit like writing an article about cows and posting the link to my favorit steak restaurant -P

ECU testing & technical information
ECM Codes Revealed

153.96.161.212   shelmton