check engine light O2 sensor already replaced same codes still popping up after replacing old O2 sensor
I went to AutoZone after seeing a check engine light on and got a diagnostics check on my check engine light it said I have a faulty O2 sensor bank 1 sensor 2 to replace so I replaced it got my codes cleared even reset the codes by disconnecting the battery and drove over a hundred and fifty miles already I still have the check engine light on I went to AutoZone and got another diagnostic check and the same code is popping up still saying I need a new O2 sensor that bank 1 sensor 2 is faulty what should I do what else could be the problem if I have a brand new fitted O2 sensor in there already
Experienced mechanics share their insights in answering this question :
Hi there. What you received from the parts store was a code retrieval, not a diagnostic. The codes are set when a fault is detected against normal operating parameter. The computer does not know what caused the fault, only that the fault meets the criteria for this code to set. There could be a problem in the wire harness, converter, or the ECM. The code and data are needed to properly assess the direction that a diagnosis needs. I strongly suggest having a qualified technician perform an inspection to avoid replacing unnecessary parts. Your Mechanic has several available technicians that can assist you with a check engine light inspection.
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If the mechanic completed the O2 sensor replacement, reset the codes and the error code was triggered again, it is possible that the catalytic converter is damaged and needs to be replaced.
The Light Stays On
If you`re experiencing this, don`t panic. You may think that there is still a problem with the car after the repair, but it`s because the light needs time to reset. The car`s internal computer only resets after a set period where it checks all of its sensors once more.
Because the sensor can no longer regulate the fuel mixture, a car`s emissions will go up. While O2 Sensors are robust, they are exposed to the elements, and will deteriorate. Once this happens, the sensor will throw a fault, and thus the Check Engine light comes on.
In most cases, successfully repairing the issue that caused your light to come on will cause the check engine light to turn off automatically—but only after 10 to 20 “cycles”.
So why is the light still on? Here`s something you probably don`t know: after clearing the car`s computer you will need to drive for about 50 to 100 miles. As you drive your car the computer will monitor all the sensors and register the results.
Yes. While the damage may seem small initially, the longer you drive with a bad oxygen sensor, the worse the damage will become. Eventually, you may experience rough idling, poor acceleration, engine misfires, an illuminated check engine light, and failed emission tests.
Disconnect both O2 sensors (front and rear). Start the engine and allow the vehicle to idle. After faults have stored: Cycle the ignition OFF/ON 2 times with a 10 second pause in between key cycles.
Yes, a bad spark plug can confuse your car`s internal computer and trigger the O2 sensor code.
Why do O2 sensors fail? Since the oxygen sensor is in the exhaust stream, it can become contaminated. Common sources of contamination include an excessively rich fuel mixture condition or oil blow-by in an older engine and engine coolant being burnt in the combustion chamber as a result of an engine gasket leak.
No reset is required. Most of the time, there`s a problem when the check engine light is on.
It is a good idea to let your car sit with the battery disconnected for at least half an hour, this will reset the computer allowing your O2 sensors to not have to work against the PCM.
Cycle the ignition OFF/ON 2 times with a 10 second pause in between key cycles. Check measured value block (MVB) 41/4 and 136/4 to verify they have both changed from a 1 to a 0. This forces the ECM to re-learn the O2 sensor adaptation.
If the problem was a bad sensor, it will work immediately. It might take a couple of drive cycles to auto clear the codes from the ECU. If another issue caused the code, like a bad wire harness, then the light will never go off until that gets fixed. Same thing for a bad cat convertor.
Cycle the ignition OFF/ON 2 times with a 10 second pause in between key cycles. Check measured value block (MVB) 41/4 and 136/4 to verify they have both changed from a 1 to a 0. This forces the ECM to re-learn the O2 sensor adaptation.
Once your sensor is reinstalled and plugged back in reconnect your battery. With any luck your check engine light will be off. Take it for 15-30 minute test drive to see how it runs.
If the problem was a bad sensor, it will work immediately. It might take a couple of drive cycles to auto clear the codes from the ECU. If another issue caused the code, like a bad wire harness, then the light will never go off until that gets fixed. Same thing for a bad cat convertor.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
check engine light O2 sensor already replaced same codes still popping up after replacing old O2 sensor
ANSWER : Hi there. What you received from the parts store was a code retrieval, not a diagnostic. The codes are set when a fault is detected against normal operating parameter. The computer does not know what caused the fault, only that the fault meets the criteria for this code to set. There could be a problem in the wire harness, converter, or the ECM. The code and data are needed to properly assess the direction that a diagnosis needs. I strongly suggest having a qualified technician perform an inspection to avoid replacing unnecessary parts. Your Mechanic has several available technicians that can assist you with a check engine light inspection.
O2 sensors changed, but check engine light still showing code after clearing it I checked fuse. Wires are good and used Denso OE.
ANSWER : Depending on what the code was for will determine if the oxygen sensor was to be replaced. If the conditions were for a rich or lean mixture and it said oxygen sensor, then the spark plugs and wires could need replaced if its a rich reading or the fuel injectors could be clogged or not working if its a lean mixture. If the code said that the oxygen sensor was bad, then check the harness and see if there is a break in the wiring or a short to ground in the wiring from the oxygen sensor to the main harness. If you need further assistance with your check engine light being on, then seek out a professional, such as one from Your Mechanic, to help you.
Diagnostic code read o2 sensor bad, replaced o2 sensor, cleared code but engine light came back on, is it caused by bad air filter
ANSWER : Hello there. Typically jump starting a vehicle doesn’t trigger an OBD-II error code. However, one of the most common misdiagnosis issues with the P-2270 is replacing the O2 sensor before diagnosing if there are any exhaust leaks. Obviously, you’ll want to check for the exhaust leaks first, repair the damaged component, and then clear the codes before scanning the vehicle again. Sometimes the electrical harness attached to the O2 sensor is damaged or dirty which will also trigger this error code. The noise and vibration may be an indicator of a loose exhaust pipe, which may be the source of the error code staying on. If you need any help, have a technician from YourMechanic come to your home or office to diagnose your Check Engine Light and make the necessary repairs.
Service engine warning, MAF code and O2 sensor code, along with check suspension light are turned on
ANSWER : Hello, it sounds like you have quite a few things going on. I am going to do my best to break them down for you.
First if the engine is very loud when idling and the belt has already been replaced, there may be an issue with the tensioner or idler pulley.
Next, the Navigator is known for needing service to the air suspension system as it gets up in miles, the most common causes of these are the air struts themselves have failed, or one of the air lines has a leak.
Lastly, if the O2 sensor and MAF are continually coming back after the sensors have been replaced, the most common cause would be either an exhaust leak or a vacuum leak.
Qualified technicians such as the ones at YourMechanic will be able to diagnose these issues and recommend the best path to repair, starting with a diagnosis of your warning lights.
So I had two codes come up for two of my o2 sensors..replaced them both and check engine light is still on…my mechanic seems to
ANSWER : Hi there:
Although it’s hard to say if there was serious damage done to your ECM during this service, it’s more likely that the stored error codes were never cleared from the ECM, and that’s why the warning lights still appear. This is a common oversight with some mechanics, but if you have a mobile mechanic complete a check engine light inspection, they should be able to clear those stored codes and determine if further damage has occurred.
Check Engine light comes on, mechanic replaced o2 sensor but light still comes on.
ANSWER : Hi there:
If the mechanic completed the O2 sensor replacement, reset the codes and the error code was triggered again, it is possible that the catalytic converter is damaged and needs to be replaced. However, it’s also very common for the electrical harnesses that power these sensors to become frayed, damaged or faulty; which can also trigger the check engine light. It’s not advisable to drive a vehicle with a damaged catalytic converter for extended periods of time, as it can cause damage to internal engine components.
check engine light code said replace cam sensor will not crank with new sensor but wiil crank with old sensor
ANSWER : Hi there:
That is a very off symptom you’re describing. Without being there to phyisicaly inspect your Nissan, the only thing I’d guess that might be causing this is if the cam sensor you installed was the incorrect one, or perhaps the electrical harness created an electrical fault; causing the ignition relay to not send a signal to the starter relay. You might want to have a professional mobile mechanic complete a car is hard to start inspection; so they can determine why you’re having this issue.
I have a 96 Ford ranger with cel p0340 I have recently done a timing belt, engine runs great replaced cmp sensor cel still on
ANSWER : Hi There,
This may happen for a couple of reasons. First, check to be sure that the connections to the sensor are clean and not faulty or broken. Secondly, check to be sure you replaced the correct sensor as there are two camshaft position sensors in some applications. If you need further help with this, please reach out to us here at YourMechanic as we are always here to help.
