I have an 2wd '01 Ranger with a 3.0 and auto. The check engine light came on. I borrowed a code reader from the auto parts store and pluged into the diagnostic port . The reader would not power up, when manually switched on the reader does not recognize that it is connected. I have tried readers from two different stores with the same results. Could my plug be bad? If so, how do I test? Any advise is greatly appreciated!

 

You need to turn the key to the "ON" position to supply power to the diagnostic port.

 

I have tried the reader with the ignition switched in the "On" position , the "Off" position, the "Acc" position and with the engine running. The reader does not power up at any point, and when switched on manually does not recognize that it is connected.

 

Make sure the F2.17/20amp fuse in the central junction box isn't open.. It powers the cig lighter/DLC...

 

That was it! A blown fuse, replaced and all is well again. Thanks for your help!