alright i have a 99 blazer and now this code (P0452) is appearing ,emissions control low read. what should i check to get rid of this? thanks

 

Code P0452 is fuel tank pressure circuit low. The first thing I would check is the fuel filler cap. The cap might not be sealing properly. That would be the first and cheapest thing to check.
If that doesnt do it then there may be a problem with the fuel tank pressure sensor, which is located in the fuel tank on the fuel pump assembly, or the wiring or connectors.
Lets hope it's just a gas cap.

 

Yup, I concur. When you fuel your truck, do you leave the engine running? Do you click the gas cap atleast 3 times after it becomes tight?

You should always fill up a vehicle with the engine off. And especially on GM vehicles, always turn the gas cap until it clicks 3 times when finished fueling. Try just tightening the gas cap down more and see how that goes. If the code is still present, replace the gas cap and continue on.

 

yeah i've already replaced the gas cap and the code is still on. this sucks

 

The code needs to be cleared with a scanner or it will reset , if the cap fixed it after 40 warm up cycles.
So even if the cap fixed the problem, unless you cleared the code with a scanner, it'll be a while before you know for sure.

 

can't you pull battery terminal for like 10 min. or something and clear the codes?? Then it'll only store new/current codes if any?

 

as soon as i clear the codes it pops right back up. so it not the gas cap , i think maybe i should check the vacuum line(s) from the tank....?

 

bump

 

Did you check the vacuum lines?

 

How about the fuel tank pressure sensor make sure there is a good connection it should be back on top of the gas tank some where...

here is the price at gmpartsdirect.com:

Part #9377680
Fuel Tank Meter Sender/Connector
SENSOR
$22.03 Gm Parts Price
$9.95 Shipping
$31.98 Total

Some states will require sales tax so the price reflected may be higher....but i checked it with my connection...


Also maybe check out the Evap canister filter???