Secondary Air pump issue

Hi, I have the same vehicle (2000 V-6 3.8L), acquired from CT, and the same problem. Replaced the smog pump; fault reoccurred. My solution: Have a look VERY CAREFULLY at the wiring harness. In my case, the place where the previous owner tapped into the black ground wire going to the PCM Relay (for diagnosis, maybe) had allowed corrosion to get in, and that wire was broken, although the insulation looked decent. Only when I tugged on it and gave it a close visual inspection did I discover the flaw. This was the black w/yellow stripe wire from the PCM to the relay (one of the 5 wires). So from your problem description, since you have replaced all 3 involved components with "known good", the conclusion is that you may have an intermittent connection or a broken wire in the harness that will work sometimes, and not work other times.

The diagnostic procedure is to check the voltages on all the wires going into the PCM relay (see wiring diagram for C155, as that connector is known).

Yes, it's a VERY TOUGH problem. I see you're posting from AZ; has the car lived there all its life, or is a refugee from the salty NorthEast? Corrosion issues are (unfortunately) common with cars that move south from the Rust Belt...

Good Luck!

Correction: the Black/yellow stripe wire on pin 1 is the +12v Power (Hot at All Times), not a ground. The official name for the 5 connector relay is the Air Injection Reaction (AIR) Relay. Sorry about the mistake...