my car won't pass smog trouble code p1794?

P1794 Powertrain Control Module Battery Direct Power Circuit. Basically, the PCM is not passing power properly, Check all fuses, especially dome light, as it powers a circuit to the PCM. Pull them and check not only for continuity, but for corrosion on the blades and clean/replace as necessary. The next is to clean the battery connections and ground connections from the battery to the engine and body. These are the most common issues. If the problem persists, have the alternator output checked.