OBD Communication Failure

The current smog inspection requires that the smog machine communicate with the vehicle On Board Diagnostic (OBD) system. All vehicles sold in the US since 1996 have a standardized On Board Diagnostic system, this system monitors the engine and transmission control systems and warns the driver of faults by turning on the malfunction indicator (check engine) light. During the smog check communication must be established in order to confirm proper operation of the OBD system, check for fault codes, and readiness status. Just because you have an OBD communication failure does not mean there is a problem with your 1996 Isuzu Rodeo, the fault could be with the smog machine. You can verify operation of your OBD system by using a code reader to access the system. AutoZone might do this for you for free. If communication is established with the code reader then chances are the OBD system is functioning properly. The communication fault may be a software issue between the smog machine and your Rodeo. It may be necessary for you to go to a different smog check station with a different make of smog machine to have the test properly completed.

Its either a blown fuse, or if you installed an aftermarket radio/took the stock one out that messed with the obd communications....simply replace the fuse or unplug your radio when you get it inspected and it will work.