my check engine light came on I had it checked and the code was p0440 is this something I can fix myself or do I need a mechanic?

This is a emission control malfucntion,could be clogged vacume canister,or just a sensor,best left to pro to fix,this.

I had a test done and 4 codes came up what should I done

I replaced the gas cap now it might be the upper lower oxgen senor. Could that be the problem.

I had a test done and 4 codes came up what should I done Could you call me I would like to talk 716 605 4428

I would like to talk to you. 716 605 4428

When i did the obd ll test came up po440 I replaced the valve under the hood n ran fine after There is a video on utube showing how to replace the sensor valve Its located on the right side of your engine Has two ends of which hoses are attached n is black This is for the 2002 envoys

I replaced my cap with a GM cap and cleared code. The light has come back on and the “tighten cap” light has came on again, but vehicles running normal. Next thing I’ll be trying it running seafoam through the vacuum system to clean off sensors

It’s an emissions code could be faulty gas cap seal,it could be the sensor down where the the gas filler pipe goes in the gas tank,easy to install, or it could be the vacuum purge in the engine compartment and possibly the charcoal canister has a vacuum leak. It’s all got to do to make sure that the fumes in your gas tank get returned through you engine instead of the atmosphere that causes pollution. You can go from the easy one which is the gas cap, if you have a battery powered voltage tester u can test each sensor, but if it’s one of the two sensors I would replace them both for less then a hundred dollars through Rock Auto .com under a 100 bucks for both units.... I know it sounds hard believe me it’s not, unless you want to pay someone 300 or more dollars... I hope I could help u...if you have a computer or an IPad type in the 440 code and how to fix it, it will walk you right through the whole process......John