This 2000 Buick Century was towed in with a no crank, no run condition. The first course of action is to check codes and data. Only one problem the scan tool will not communicate with the PCM or any other module on the car.
Well somewhere along the way someone else tried to do some testing and really screwed things up. The purple wire, terminal 2 of the DLC had been probed with something other than the proper terminal and a heavy hand was used. This compressed the spring tab in the terminal. With the tab compressed it would not make a connection to the scan tool mating terminal.
Terminal 2 is located on the top row of the connector and two positions from the left side, in the following picture. Click on the picture below to enlarge it.
The terminal was badly damaged so I cut of the old one and spliced on a new terminal.
Data stream was back but the engine still would not start.
I looked for codes and at data in all of the modules and found that there was still no communication with the BCM, body control module.
That is going to be a different post though. Click here to see that repair.