Recently took my blazer into the shop. Had a bad IAC pump. Was throwing the notorious secondary air injection fault error before I had the repair. There was a blown fuse in the fuse box above the secondary air pump (I replaced the fuse before the repair). I got the truck back a week ago, and the check engine light was off.

I drove around 400 miles since I've had the truck, in all conditions. Yesterday when I took it in for inspection, I failed due to no reading coming from the secondary air pump and the catalytic converter.

Anyone have any suggestions?

 

What year, make, model, mileage etc.....?

 

2001 s10 blazer 4wd 5spd 104k

 

When you replaced the pump any chance you reversed the the two vacuum hoses on the switch on the pump? I dunno if there's a check valve in there and it would only let it work properly in one direction? Check the IGN E fuse in the underhood fuseblock (powers the relay coil for the pump). I assume you replaced the 30A maxifuse, did you also check the smaller 10A fuse on that block (powers the vacuum solenoid switch on the pump)?