Our 300,000 mile 1996 Dodge Dakota Sport (3.9L five-speed 4x4) just had the "check engine" light warning. After running my scanner tool, instead of showing a code(s) the screen shows the word "fail". Same thing when I try to clear the codes. This happened once before quite some time ago so I had the local AutoZone try to retrieve the code(s) and their own scanner would not read anything either. Any known remedy to this situation? The vehicle still starts, runs, and drives. I will probably try to clear the check engine light by temporarily disconnecting the battery but I would still like to find out the trouble code in the system. My scanner uses power from the vehicle and it does turn on when plugged into the vehicle port and the function keys on the scanner also work. Thank you.

Thank you.

 

Communication is on a pair of wires from the OBDII port, they like to get pushed out of the connector, so the scan tool can't connect. have a look, make sure they are clean, and in the right spot, and try again.