emissions test fail, couldn't read computer
 

Person at emission testing said he could not read the computer on my 96 Dodge Ram truck. He said check the fuse to the ECM. Can not find in the diagrams an ECM fuse.

If the truck starts and runs, the ECM is most certainly getting power. Likely just a problem with the OBDII connector. Will the cheap parts store code readers talk to the PCM?

If the IOD fuse has popped, it will keep the obd stuff from communicating. It's the one with the cover on it in the fuse block on the dash.
I remember another fuse causing the same issue with the obd port, but I don't remember which one. Good luck and happy hunting. :)

if the scan tool will not power up; check for power at pin 16 of the data link connector. this pink wire should have battery voltage at all times. If no power, check fuse 17 in the fuse block

if the scan tool powers up but will not communicate with the ecm, check the communication lines pins 6 & 7 of the dlc for voltage.

Check cig lighter fuse

nevermind... i found it. long day...