My Honda Accord 2000 runs great but the check engine light keeps going on. I keep getting things fixed (i.e. oxygen sensor, two other sensors, transmission etc) but light keeps going on about 2 days after I get something fixed. Now the light is saying 780, 700, and 1470. But the car is running great.

the code refers to the heated oxygen sensor (HO2S) and not the O2 sensor which is a different sensor
It is a generic code and refers ti injector and fuel problems
The misfiring can be from injectors as well as plugs so check for fuel pressure and blocked fuel filter

My first thought was fuel pressure. Low fuel pressure would cause the engine to go lean but not set a code for the actual problem.
Is it possible the fuel filter is clogged ? Have you checked fuel pressure?

This code does not mean to replace the sensor , testing is what is suppose to happen .
P0131 O2 Sensor Circuit Low Voltage Bank 1 Sensor 1

Honda Civic P0131 02 Sensor Diagnosis

DTC P2270: Rear Secondary HO2S (Bank 1, Sensor 2) Circuit Signal Stuck Lean

Is this the only code that is coming up? If so, replacing the Bank 1 Sensor 2 Oxygen sensor should fix it. If there are any other engine/drivetrain/emissions related codes, I would recommend ignoring this code for now and fix the other things first, then retest the vehicle to see if this code comes back.

For more information about locating oxygen sensors and repairing oxygen sensor codes, please review the following article:

Which Oxygen Sensor Is It?

What Else Could Be Wrong?

The service check connector is a BLUE, 2-pin connector located in the area of the right side kick panel. You may have to remove the kick panel to find it. It is normally "taped up" to the wiring harness and should be there unless someone has previously un-taped it and left it "dangling". You can jumper the connector with a paper clip and turn the ignition on to get the check engine light to output flash codes.

The only thing "common" about fixing the check engine light is that you MUST get the fault code so that you will know which of the many circuits monitored by the computer is malfunctioning. When you find out which circuit is malfunctioning, then you must diagnose that circuit to find out why. NOBODY can tell you what to fix or replace without FIRST retrieving the fault code.

1993 Honda Accord was equipped with 1 oxygen sensor. It is located in front of the catalytic converter. There is no second oxygen sensor. Toyota began using downstream oxygen sensors to monitor the catalyst in some of the late 1995 models. (getting ready for mandatory OBDII which began in 1996)

check engine light is set when the computer gets bad readings from sensors. you can try an auto parts store to get a reading of why a light came on. autozone and advanced auto parts both do it for free. then you can get the parts from them to fix it. it would be about time for an oxygen sensor to go bad. this should reduce performance and gas mileage. any diveablility issues with the car? if this helps please reply and good luck

o2 sensor is very important part to the engine when it come to the fuel economy. o2 sensor send information to the computer (ECU) which compute and calculate ratio of burnt exhaust gases. if the engine is not run properly either is too lean or too rich the o2 sensor will detect it as the car will triger the check engine light. you can drive the vehicle which will not hurt it as long you can tolerated the light however the car will get terrible gas mileage and poor performance as the ECU will try to lean the engine out itself. o2 sensor is fairly cheap to replace and fix. Let assume the car get 30 mpg on the high way, running with check engine light/bad o2 sensor will change the gas mileage to 18-25 mpg. If the car is V6 make sure you replace o2 on both side. good luck!

Did you reset the ECU after changing the sensor? If not you need to (procedure in 2nd pic below), that way the fuel trims are reset and the ECU can re-learn the Short term and Long term fuel trims. this could be the cause of the difference in MPGs.

An O2 sensor will have no effect on RPMs/MPH. the only thing i can think of that would effect this besides changing gear ratios, would be changing the overall diameter of your tires or possibly a slipping clutch.

Check the codes on the ECU. here is the procedure:

(CLICK PICTURES FOR FULL SIZE)

Try driving for a while, it should go out. Unless fixing the oxygen sensor uncovered a new problem. Maybe the MAF sensor is going bad.

i think its a computer glitch or it you might have replacesom parts with a non honda part,it maybe not syncing with hondas's sensor..