NA car, California emissions. Last couple of months I've been muddling through secondary air system problems. My experience with system errors has historically pointed to the pump itself, and this car had a used one installed many years ago, so I started by pulling the pump, only to find that the motor is good, quiet, and the relay energizes and switches power just fine--on the bench. Further investigation showed that my solenoid valve was NOT working and the valve on the exhaust manifold had a bad diaphragm too. I replaced that with a new unit and got a good, working solenoid check valve. Everything is back together and no more codes, but I haven't heard the motor run in the few weeks since finishing.

Two things I've found on the web:

First, that there is no regular fuse for the motor, but a fusible link--I just don't know where it is and cannot find any info on that. I admit I didn't probe the plug for power TO the relay when I had it out--as the battery was out too.

Second, I've found a couple of posts about the circuit in the ECU that controls the motor developing a fault, only fix is to trace and repair in the ECU or replace the ECU (easy to find).

After doing some other work yesterday, I started the car cold, and it was cold out--about 40 degrees. After a few seconds I could hear and feel pulses in the line to the air pump, so it would seem the porting system is activating. Pump did not run though. Gotta be either signal to the relay or power for the pump? I'd love to find that fusible link and check it, if anyone can point me to it.

Thanks, and season's greetings.