We'd recommend you first try to get your Dodge truck smog checked at another
smog test center, maybe the smog station that performed the smog check last
time. We're thinking if there is nothing wrong with your Dodge truck's
computer system maybe the smog machine's OBD II connector had a problem. Try
a different smog test center first. If you get the same problem (no
communication) you will then need to have the problem diagnosed by a smog
check repair center. Your Dodge B1500 may have a loose OBD II connecter
wiring, or in the worst case scenario, a defective engine control computer
(ECU).
The smog repair shop will check the connector wiring ensuring there is power
getting to the connector (and a good ground) and no breaks in the
communication wire between the connecter and ECU.