Q: My check engine light came on, changed O2 sensor. Check engine light was still on, then three days later went off.

asked by on July 29, 2017

My check engine light came on and was solid, not blinking, my mechanic reset my sensors, but it didn't help. Took my car to an exhaust place, they said it was my O2 sensor or my catalytic converter. I had them change my sensor, drove 10 miles and my check engine light came back on, so I figured it was the catalytic converter. Three days after that, the check engine light turned off. I called the exhaust place and they said it was ok to continue driving. How do I know for sure what is going on with my car?

My car has 148377 miles.
My car has an automatic transmission.

Oxygen Sensor Replacement $108.80 - $905.23 Get a Quote
Catalytic Converter Replacement $291.63 - $3214.07 Get a Quote

Hi There, The last diagnosis is correct in that the sensor replaced caused the check engine light to turn off. In some cases they do not always turn off immediately and take a bit of driving for the computer to recalibrate and recognize that the problem has been corrected. In your case, it sounds like the oxygen sensor is what caused the code to be triggered. This can also sometimes cause codes to be triggered that may reflect problems with the catalytic converter as well since the oxygen sensor reads the exhaust gases coming from the catalytic converter.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

location of bank 2 camshaft position sensor B on 2012 toyota tundra 4.6L

The camshaft position sensors on most engines are located directly below the valve cover within the cylinder head. This applies to both Bank 1 and bank 2.

Car shakes in idle and reverse

Hi Cyrel. Thanks for contacting us today. To be honest, there could be multiple issues going on here. It's more than likely that you have a loose or damaged vacuum line or your ignition timing is off. A damaged torque...

Rattling noise as I change gears and accelerate

Random rattles are difficult to pinpoint without actually hearing it but I can list a common cause or two. Considering the age and mileage of the vehicle, the exhaust system is a good place to look. Exhaust systems are commonly...

Heater and air conditioning fan stuck on low

The push button panel for your climate control is also the control unit. It uses the signals from various temp sensors to decide what to tell the climate control what to do. It also decides on the fan speed and...

Clicking noise at lowspeed turns, vibration when stopping abruptly, mechanic said need axles & no grease left. how long do i have?

As for "how long you have", unfortunately you needed to replace them when they were mentioned. With no grease to protect and lubricate them, the clicking noise you hear is the joints basically grinding themselves apart. Is this potentially dangerous?...

Car feels like it is going to cut off

Hi, thanks for writing in. I'd be happy to offer my insight. You engine may have carbon build up on the valves and clogged injectors. I recommend having the combustion chambers and injectors cleaned. Once this is done then I...

Battery is dying, jump start did not work - 2013 Cadillac XTS

To find a way to decrease the delay for the lights, consult the owner's manual for the specific steps to change the delay. Otherwise, there may be a faulted circuit allowing a component to stay powered up with the ignition...

My car will only turn on when my foot is on the gas but turns off when its not

Hey there. This could be from a couple of potential problems. Your car has what is called a throttle position sensor which monitors the position of your foot on the gas pedal and relays this to the computer which then...

None of the power windows work

There are two likely causes of this symptom: Either the driver front master window control switch has gone bad, or the control module for the windows has gone bad. The most likely would be the switch. The driver front door...

Related articles

How Long Do Wiring Harnesses Last?
Car wiring harnesses connect all the different electrical systems and components in a vehicle. Wiring harnesses can last the lifetime of the vehicle.
How Air Bags Work
Designed Designed to protect the occupants of a vehicle in the case of an accident, air bags inflate when the vehicle collides with another object, or otherwise suffers a sudden deceleration. Absorbing the energy of the impact, vehicle owners need...
Can Sensors Be Cleaned or Do They Need to Be Replaced?
In In most cases, sensors for your automobile will need to be replaced if they fail, but depending on the type of sensor and its location or function, some can be cleaned and reused. Sensors can come in many...