2001 S-10 Blazer, 4.3, 4WD, 4Dr, 107K miles
This has been the wife's vehicle but since car prices have come down so much I got her a new car a few months ago. I am trying to get this thing to pass an IM test so I can drive it and keep the miles off my truck.
The Check Engine light has been on for 4 or 5 years now but have not seen any decline in performance. When we 1st moved here (AK) about 3 years ago I took it in for the IM test and the mechanic said it was the MAF so I replaced that. Light stayed on - Went back to get it checked again and he reset something so the light would go out long enough for him to pass it?? Anyway, it is now time to get it inspected again and the mechanic that did the 1st IM test is no longer around.
Took it in last week and it came back with P0128 so I changed the t-stat and added a little coolant. The other code is P0410. The mechanic recommended I replace the air injection pump. I replaced the air pump and solenoid with a kit from GM ($400). This kit re-routed the hose and put the solenoid between the battery and the coolant bottle. I also replaced the air sensor that is behind the MAF. I then unhooked the battery for a while which I believes clears the codes.
The light is still on, and when I took it back today sure enough both codes are still there?? What am I doing wrong?
I guess my question is where should I go from here?
I did pick up a Engine Temp Sensor on the way home but can't figure out where it goes? The Haynes manual and other posts say it's on the front of the intake manifold but the only thing I see is a place where it could go - just below the t-stat housing but there is just a plug there.

Any help would be greatly appreciated!!
Thanks!
-Pete

 

Remove your battery and inside your fender is a 30 amp fuse and relay that powers the air pump. Check it. That's a possibility for the PO410, could be a bad sensor causing the other one. It's located on the drivers side of the motor near the spark plugs. Might be easiest to get at with drivers front wheel off.

 

The code P0128 could also be caused by a faulty ECT sensor (engine coolant temp) or a faulty IAT (intake air temp) sensor. Make sure the coolant is up where it's supposed to be. The easiest way to test it would be a scanner that reads live data or a Tech2(a GM scanner). You need to see what the computer thinks the ECT is at, it will show you a reading for both the ECt and IAT and it'l show if they are working correctly or not. If you mean you picked up an ECT sensor it's located right next to the thermostat, lol. It's literally connected to the thermostat housing.
For the other Air injection code i'd check the fuse if you already replaced the unit. Try disconnecting the battery for a min or 2. That will clear the codes, and the air injection one shouldn't come back for a little bit anyways.

 

Thanks gentleman! The 30 AMP fuse is blown and I found the ECT sensor on the drivers side by the spark plugs. Probably going to have my 2 year old replace that because she is the only one with hands small enough to reach it Anyway, once I get everything back together and run the codes again I'll let you know how it turns out.
Thanks Again!!!

 

wondering how this turned out lol