I have a 2001 Mitsubishi eclipse check engine light on the code was O2 sensor bank1 sensor 1.i changed the sensor reset the system and the same code came up what do I do now?

These may be few possible reasons why the check engine light won't go away after replacing the O2 sensor in your 2000 Mitsubishi Eclipse V6

·The wrong O2 sensor was replaced or the O2 sensor is properly connected to the wiring harness(any signs of damage or corrosion).
·Sometimes, issues with the engine, such as misfires, vacuum leaks, or problems with the fuel system, can trigger the O2 sensor to report a problem. Ensure your engine is running smoothly and there are no other issues that could affect air/fuel ratios.
·The new O2 sensor is defective. If the O2 sensor is working properly, then the check engine light could be due to another problem with the exhaust system, such as a leak or a problem with the catalytic converter.
·Problem with the wiring to the O2 sensor. If the wiring to the O2 sensor is damaged or corroded, it can cause the sensor to malfunction and trigger the check engine light. To diagnose the exact cause of the problem, you will need to have the car scanned by a qualified mechanic. The mechanic will be able to read the trouble codes from the computer and use that information to pinpoint the problem.

The 4G64 (2.4L) engine is an in-line four cylinder engine. The cylinder numbers are assigned as 1-2-3-4 from the front of the engine (timing belt side). This engine is fired in the order of the 1, 3, 4 and 2 cylinders.
Feb. 27, 2009

Spark Plug Order ' Mitsubishi Eclipse 3G Club

Pictures

https://www.google.com/search?q=firing+order+for+2007+Mitsubishi+Eclipse+Spyder+2.4L

Strictly speaking you have two fuel / air sensors in the manifold for the catalytic converter and two O2 sensors after the cat.

Details here

https://www.google.com/search?q=2007+Mitsubishi+Eclipse+Spyder+2.4L+Replace+o2+sensor

buy original equipment manufacturer sensors (OEM). Their job is important to engine management.
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Start buy replaceing the o2 sensor after the cat first o2 sensor if bad will give wrong reading i normaly tell the person lets try replaceing 2 o2 before spending 900 on a cat

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Its possible. It depends on what the actual code is and what the other O2 sensors are doing.
Trouble codes are only a guide for the mechanic to use in troubleshooting, not a command to replace a part.

Contact a Mitsubishi dealer for advise , could need a new ecu , hard to say without seeing vehicle

Looked up the code. Means fuel trim malfunction bank 2. Switch your o2 sensors out and see what happens. If the code changes to p0171, then the o2 sensor is bad. If it doesn't, you need to check for misfires or exhaust leaks. Google 'fuel trim malfunction bank 2' for more info.

Passenger side, after the catalytic converter.

A dirty carbon canister (part of the egr system) caused by topping off your gas tank can cause this. Try not topping off your gas a few times to see if it will go out. You may have to reset the engine computer, to do so, unhook the battery for at least 20 seconds. (after you haven't topped off your gas a few times if the light doesn't go out automatically)
Make sure you have any security codes or radio codes before you do this.
If it doesn't go out then the O2 sensor in that bank will have to be replaced again. If you replace it again, do not top off your gas tank.
Make sure you use the correct heated sensor, some places sell universal ones that do not work right, or in some cases at all.

Explanation: Topping off your gas (overfilling) can cause raw gasoline to run into the egr system causing all kinds of problems on some models. In some cases, raw gas can run into the exhaust when the engine is warming up, over time, damaging the front O2 sensor/s. When the gas pump stops, do not add more to attempt on getting the most gasoline in your tank.

You can take your car to Auto Zone and they will scan the codes for FREE. They will also let you know the part causing the problem. 99% of the time it's a sensor that you may be able to replace yourself if your handy with cars. Without the codes, it's random guessing to fix the problem.

make sure there is enough anti-freeze in the radiator. Also another reason it could be heating up is if the fans aren't kicking on