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In this video, you will learn 5 symptoms of a bad or failing oxygen sensor (upstream). Watching this video will help you diagnose to see if it is time to replace your oxygen sensor. You will also know how an oxygen sensor works. This video also teaches you where the oxygen sensor is located. You might be experiencing poor performance, failed emissions, rough idle, bad mpg, and a check engine light. Some of the engine codes you might retrieve are P0150-P0167.

I hope you guys are all having a productive day easy out of fix here and today we’re gonna learn symptoms of a bad oxygen sensor the purpose of the oxygen sensor is to measure the amount of oxygen in the exhaust system most cars have two oxygen sensors one before the catalytic converter and one after some cars can have three or even four depending if you have two

Catalytic converters today we’re going to be focusing on the sensor before the cat once this oxygen sensor gets hot enough to function the ecm uses the data to either add or reduce fuel by controlling the fuel injectors to achieve the perfect air slash fuel ratio for example if the sensor measures a rich condition which means more fuel and less air the ecm is going

To reduce fuel if the sensor measures a lean condition which means more air less fuel the ecm will command more fuel the average life expectancy for an oxygen sensor is around 100 000 miles so the first symptom you might be experiencing with a bad oxygen sensor is having your check engine light on here are some codes related to a bad oxygen sensor now your oxygen

Sensor can still be faulty with no check engine light so let’s move on to the next symptom the second symptom you might be experiencing with your car is poor engine performance the better your car can come to a perfect burn the better performance it will have now if you have a faulty oxygen sensor it could be sending a false rich or lean condition to the ecm the

Ecm will then try to fix the problem that doesn’t exist by adding more or less fuel messing up the air slash fuel ratio this can be the reason why your car has been sluggish this leads me to my third symptom a rough idle since the ecm is getting faulty oxygen data from the sensor it messes up their slash fuel ratio and combustion this as we know will result in

Poor combustion efficiency which explains why your car is shaking when you’re parked or at a red light the fourth symptom you might be experiencing with your car is having poor gas mileage since the oxygen sensor is a huge influencer to the decisions that ecm commands for fuel injection to achieve the best air slash fuel ratio if it sends a faulty signal of a

Lean condition or in other words more air less fuel the ecm will want to add more fuel this unneeded extra fuel is the reason why you have to stop by the gas station more often adding more fuel opens up a new rabbit hole which leads me to the next symptom a failed emissions test since there is more fuel than what is actually needed the rest of it has nowhere to

Go but to go through the catalytic converter and out the tailpipe sure the catalytic converter was designed to reduce harmful gases for the environment but it was never designed to convert a massive amount this is the reason why you’re failing the emissions test a quick tip to see if your oxygen sensor is bad is by unplugging the connector doing this will force

Your car to operate in open loop which means the ecm is going to be using other sensors to calculate the air slash fuel ratio like the mass airflow sensor ect throttle position map and others if you see your car running better after doing so it’s probably time for a new oxygen sensor if you plan on replacing the oxygen sensor check out the special tool that helps

Out a lot linked in the description below i hope this video brought value to you if it did please do me the favor like and subscribe so i can see you in the next video

Transcribed from video