Replaced my upstream O2 sensor. The check engine light won’t turn off.
My check engine light was on so I took it to AutoZone for a diagnostic check. It came out as my bank one sensor one O2 sensor. I replace that and now the truck is running much better. However, the check engine light won't turn off. How is this done? I've tried driving, getting the codes cleared, and disconnecting the battery.
My car has 93000 miles.
My car has an automatic transmission.
Experienced mechanics share their insights in answering this question :
When an error code is triggered and stored in the ECU, it needs to be removed by a professional mechanic using a digital scanner; and not a simple code reader. The folks at Auto Zone use the code reader and are not able to clear codes correctly in most cases. However, it is possible that a different code is stored in the ECU, as more than 100 individual codes can trigger the check engine light to illuminate on the dash. I would recommend having one of our professional mobile mechanics come to your location to complete a check engine light inspection; so they can clear the old codes and determine if other faults are found.
How to Identify and Fix Common car Problems ?
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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.
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”.
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.
Oxygen sensor failure can often be traced to one of three common factors: Age and high mileage, an internal contaminant (poisoning) or an electrical issue. One or two wire unheated oxygen sensors should be inspected or replaced every 30,000 miles.
To make sure the check engine light does not reappear, it`s recommended that you drive your car 30 to 100 miles. This enables the vehicle`s “Drive Cycle” to reset, as the various sensors need time to recalibrate.
Non-Continuous Monitors
The heater will bring the sensor up to operating temperature within 20 to 60 seconds depending on the sensor, and also keep the oxygen sensor hot even when the engine is idling for a long period of time.
Newer oxygen sensors are supposed to work efficiently for 60,000 to 90,000 miles, depending on the model of your car. If your mechanic determines that your car`s problem is due to a bad or failing oxygen sensor, the replacement shouldn`t take long and you`ll be ready to tackle many more miles on the road.
A brand new O2 Gas Sensor does not need to be calibrated, but the sensor will drift over time and will need to be calibrated. To calibrate the sensor, follow the normal 2-point calibration procedure. -For the first point, push and hold the calibrate button on the sensor using a paper clip or LabQuest stylus.
No need – just ensure the engine`s not running.
However, if there`s a problem, the light will come back on as soon as the computer runs the test that caused the light in the first place. It might happen right after you turn the car on, which might make it seem like you can`t clear the check engine light. Or it might take a couple of days to come back.
Failing Oxygen Sensor
One common issue that can cause your check engine light to turn on is a failing oxygen sensor. The oxygen sensor is responsible for monitoring the amount of oxygen in the exhaust system, and if it detects a drop in oxygen levels, it will trigger the check engine light.
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.
Read Full Q/A … : Replaced my upstream O2 sensor. The check engine light won’t turn off.
Replaced my upstream O2 sensor. The check engine light won’t turn off.
ANSWER : When an error code is triggered and stored in the ECU, it needs to be removed by a professional mechanic using a digital scanner; and not a simple code reader. The folks at Auto Zone use the code reader and are not able to clear codes correctly in most cases. However, it is possible that a different code is stored in the ECU, as more than 100 individual codes can trigger the check engine light to illuminate on the dash. I would recommend having one of our professional mobile mechanics come to your location to complete a check engine light inspection; so they can clear the old codes and determine if other faults are found.
Read Full Q/A … : Replaced my upstream O2 sensor. The check engine light won’t turn off.
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.
Read Full Q/A … : Replaced my upstream O2 sensor. The check engine light won’t turn off.
2006 Ford Mustang has check engine light on
ANSWER : There are countless potential causes for your illuminated check engine light. The mechanic manually turned off the light, but it came back on because the problem has not been fixed. The first place to start is retrieval of the stored diagnostic trouble codes (DTCs). These codes serve as a starting point for any further diagnostics a mechanic may perform. Codes will be stored anytime the check engine light is on. Since the first mechanic was unable to fix your concern, I recommend giving the professionals at YourMechanic a call. We offer expert check engine light diagnosis and repair.
Read Full Q/A … : Replaced my upstream O2 sensor. The check engine light won’t turn off.
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.
Read Full Q/A … : Replaced my upstream O2 sensor. The check engine light won’t turn off.
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.
Read Full Q/A … : Replaced my upstream O2 sensor. The check engine light won’t turn off.
Just replaced head gasket, changed crack sensor new plugs. The check engine light is on, but dim, the only other light that the dash is a normal battery indicator. The fuel pump is not running when switch is turned on, the power windows don’t work, it turns over but not firing. It’s like only one part of the system is working. Also the heater fans work even if the switch is off.
ANSWER : I would first look at the diagnostic trouble codes. Those codes are available because the check engine light is on. If the fuel pump is not running (momentarily) at key on, that fault alone will prevent the car from starting as there will be no fuel pressure. Pump output and pressure can be directly tested and you can also check for electrical power to the pump. To find out why the engine will not run, the recommended diagnostic is a no start diagnostic. If you request that service, the responding certified mechanic will get this taken care of for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
Read Full Q/A … : Replaced my upstream O2 sensor. The check engine light won’t turn off.
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.
Read Full Q/A … : Replaced my upstream O2 sensor. The check engine light won’t turn off.
