Originally Posted by pizzaguy
What I think he is talking about, is the air pump that runs at first to inject extra air in the exhaust to help heat up the Cats so they do their job well almost right from the start - saving the planet and all of that.
Not really a test, but a routine the car goes thru when it's first started and the computer sees that the Cats are "cold".
Yes, right, it also tests the pump periodically to make sure it's working. It quickly cycles the pump, usually right after your car is fully warmed up, and watches the O2 sensors to see a rise in AFRs. If you start moving during the test it stops and waits for the next idle time, like a stop light. The extra drag on the electrical system will cause a slight dimming also. The pump pulls some amps as shown with the RCM relay contacts wearing down.
