I replaced the 02 sensor in my 04 impala, and have driven 400 miles, but it still wont pass state inspection because they said its still not reading or reset. wat is the problem?

need to be city miles not freeway needs to see the stoping and going but that wont stop the light

Here's a link to your code.

Do you see a warning light ? The first step is always checking for stored OBDII fault codes.

If you cleared codes and one monitor will not set up after driving for 250 miles a code should be logged for that system failure.

Here is a previous fixya post describing the monitor set up drive cycle.
What is the drive cycle to reset computer on 2001 chey impala 3 8l v6

It's not the battery itself that's the issue. When you disconnected the battery to replace it, you cleared all the data from the computer. The computer then runs a self test of all systems to determine that they are functioning properly. There are several systems to be tested, and until they pass the test, each system is classified 'not ready'. Some system tests are done very quickly, with only one 'drive cycle', and they become 'ready'. Some systems require multiple drive cycles, and take longer. For some vehicles, specific criteria have to be met. On my vehicle, before the vapor recovery system can be tested, the fuel tank has to be between 1/4 and 3/4 full.

Some testing stations (depending on state) require all systems to be 'ready'. Some require a specific number to be 'ready', e.g., seven of nine. Find out what the requirements are, and which systems still need to complete testing, then check with a dealer for your make/model to see what is required to complete testing for that (those) systems.

make sure there is not a evedent eng. noise 1st

You can get it reset at any shop usually for cheap it takes about 10 to 15 minutes

Please read about this fault code at the link provided.

never replace parts till u know the issue--u cud end up on food stamps---------the code can be cleared by a scanner or removin batt cables fora moment------------there must be a problem with the 02 sensor--------catylitic converter-----------evap system or other air regs on engine----------get car to a mechanic with brains-not a dealership-that can test each one for air polluting

You need to replace your O2 sensor, that should clear pretty fast-does it switch slowly (talking about the upstream O2 sensor)?

-as to the evap, on some cars they won't test unless the tank is between 1/4 and 3/4 full for an extended period of time, but you might just need a gas cap.

i took the battery out of an o7 Eqinox to check the washer pump. when i put the battery back in, the car won't start & now the key is stuck in the ignition. i took the battery to be tested & it is good.