Do u have to reset any thing once you replace the o2 sensors

First replace the bank 2 sensor 1 O2 sensor. p0051 is that sensor heater circuit. These codes are always the O2 sensor, unless you see the wires are melted against the exhaust manifold. Once replaced the light will eventually go out. A code reader or scanner will turn it off.

The problem has to be fixed first.
The code probably did not say "replace sensor" but rather that the signal from the sensor was out of range.
The real problem could be the fuel system or other things.
What is the actual trouble code and vehicle info ?

Hi there:
DTC P1133 - Insufficient switching on Bank1 Sensor1 O2 sensor.


This is the O2 sensor located in the exhaust manifold. The vast majority of the time it is a faulty O2 sensor, but check O2 wiring harness for any chafing, as well as melting(resting on exhaust manifold):





To replace, disconnect the harness connector, and use O2 sensor socket to remove sensor. Once you change it, the code has to be cleared with a scanner. it wont reset itself. Most major parts stores will clear the codes for free. Make sure you get a direct fit O2 sensor. The universal ones that you have to splice into dont work right most of the time. They lose voltage in the wire splice and will reset the code.



Hope this helps; also keep in mind that your feedback is important and I`ll appreciate your time and consideration if you leave some testimonial comment about this answer.

Thank you for using FixYa, have a nice day.

There is no such code for any car. this 1999 cougar with the 2.5 engine has a code and i think you may have mixed the numbers the only code thats close is the po420.

Code po 420 is the cataylic converter efficency, this means the converter is not cleaning the exhaust to specs anymore and may be bad.

I have found that i lot of times a bad o2 sensor is the cause of this or both o2 sensors as in this car,i have found that its good thing when a converter is replaced that the o2 sensors should always be replaced. this will cost more but is the correct way to do the job. what i do is replace the o2 sensors first and then reset the light and then if light doesnt come back problem is fixxed.
there are mant people out there that say a good tech can see if the sensors are bad, ture and not,you can test a sensor by watching the reading and also changing them to see how fast a sensor can react and theres more to it but i wont bore you.


MY point is , i have replaced bad o2 sensors and then the converter is bad, now the customer is not happy as the quote just went up alot. then i replace a bad converter and then find an o2 that worked a week ago is now slowed down,
This is to keep in mind if its a converter and the o2 sensors are old replace them, they may be working now but lets say they slow down but not enough to turn engine light on which i see alot, then a year later you wonder why you must buy another converter.

Good day.

There are no monitors for O2 Sensors

You must have other issues effecting
the sensors

If your cats are 15 years old,then there
is your problem. No Efficiency,Replace
worn out cat

you have more than 1 o2 sensor are you replaceing the one that is bad plus once replaced you have to drive for awhile for computer to reset itself

Which O2 sensor did you replace?
P0141=O2 Sensor Heater Circuit Bank 1 Sensor 2,
this is on the drivers side,and the sensor after the converter

po420 is catalylic converter system efficiency below threshold, which means converter is not burning or cleaning exhaust good, i ve found that 90% of the time its bad o2 sensors they give off a false reading to computer, replace the frt and rear o2 sensors and reset engine light that should take care of problem, if cat con verter happens to be no good its no loss because new o2s should be replaced with new converter, but i think o2s will solve youe problem. hope this helps.goodluck.

That would correct the problem, the O2 sensor is on the exhaust manifold or on the exhaust manifold down pipe. If you go to Auto Zone, they will have the O2 sensor you need and also the loaner tool you may need to remove the O2 sensor. Auto Zone also can give you the step by step instructions to replacing the O2 sensor in about 30 min. Once you located the O2 sensor, disconnect the wire harness and use the O2 sensor socket to remove the sensor from the exhaust. It's like removing a spark plug, to install the new O2 sensor is just to follow the same procedure in revers to the removal. Good luck.

Reseting the cpu will clear the check engine code however it will not fix the problem that caused the check engine light to come on. The most common cause of failing emissions is the O2 Sensor. This sensor will trigger the check engine light when it is failing. The good news is that the Oxygen senser is pretty cheap and is mounted on your exhuast so it is fairly easy to replace yourself. I suggest replacing your O2 sensor the clear the computer by disconnecting the negative battery terminal and leave it disconnected for a few moments, hook up the negative again and it's all clear. Take your car back threw emmisions and you should be all set.

Hope this helps