Just replaced myMAF Sensor with hopes that this helps. I noticed another sensor between the MAF and TB going into the duct.

What is this and what purpose does it serve?

2003 Blazer 2WD,2 door.

Thanks in advance........

 

If it goes into a rubber grommet about the size of a nickle, has 2 wires in the molex plug - it's the engine air temp sensor.

 

Yep.

 

Thanks Guy's, that's it. How do you replace it/check it. Do you have to splice the wires?

Sorry, I'm not a mechanic or electrican,LOL.

I thought while I was replacing the MAF, I would go ahead as a maintance thing and replace that as well.

Thanks again...

 

You shouldn't have to replace it. Splice the wires?! Isn't it hooked up?

 

So that's the nature of this project... See how many parts you can replace?

One of the reasons a lot of us contribute here is to learn.. and help to spread knowledge. That's so when the next guy has a problem and does a search, he'll find where to look, specifically.
First.. all the temp sensors are non-wear items. they may fail but they may just as well last a million miles.
Since there's no moving parts; if they arent right, there's almost always an 'out of range 'code. But that's also a reason to have a good scanner, I suppose.

There are charts on the net, if you look, that show resistance v temp of these sensors. Also unlike the MAF or the O2's they dont have to react instantaneously so if they measure the right resistance for the temp they are in, they are good. They dont need 'cleaning'
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I was just thinking.. someone ought to make a chart of all the key engine sensor/driven elements and categorize them as to failure modes.

Dirt v wear v heat excess etc