What Does A Car Do When An Oxygen Sensor Is Bad?
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If you’re reading this article you are more than likely experiencing some recent challenges with your vehicle. Hopefully they’ve been minor and you’re just looking to know more! But let’s start with the basics: what is a sensor and what does a car do when an oxygen sensor is bad?
What is an oxygen sensor?
The oxygen sensor in your car monitors the amount of oxygen in the exhaust gases as it leaves the engine. The Powertrain Control Module (PCM) uses this data to measure the right air-to-fuel ratio for your engine in real time. The sensor is located in the exhaust system and helps with emissions control by allowing the fuel injection and engine timing to operate effectively.
Fuel tracking, transmission, MPG, as well as emission release, can all be monitored by these sensors. They compare the volume and quality of oxygen in your exhaust pipe to outside oxygen before sending the data to the engine’s computer for analysis.
O2 sensors in older vehicles usually last between 30,000 and 50,000 miles, or generally 3-5 years. Sensors with an additional heated feature can often be found in newer cars, and these latest sensors are more likely to last at least 100,000 miles or 7-10 years.
It’s important to take care of your O2 sensor issue right away since your catalytic converter is at risk, and if it fails, it ultimately may cause more damage to your car. In simpler terms, your car’s catalytic converter is there to basically turn harmful gasses into less harmful ones.
There are a few things to look out for before your oxygen sensor fully fails, since it can have a negative effect on environmental emissions and your engine efficiency. Usually each vehicle will have one catalytic converter for each exhaust pipe on your vehicle. There will be two oxygen sensors for each catalytic converter. Most vehicles only have one catalytic converter and therefore two oxygen sensors, but some vehicles can have up to four or more.
A service that used to cost a few hundred dollars with routine maintenance now can range from $500 to $2,500 depending on how many oxygen sensors are in your vehicle. Yikes! This may not be the case depending on how late you catch it, but in a worst case scenario this is a likely range to fix and repair. Since that’s not the goal that we would hope for, what are some signs you can catch and what does a car do when an oxygen sensor is bad?
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1. Check engine light comes on
Onboard diagnostics are mounted in both cars and light trucks to identify engine-related issues that affect the emissions control systems. The check engine light indicates that a fault in the vehicle’s emissions, ignition, power, or exhaust systems has been identified by the onboard diagnostics system.
You shouldn’t neglect it because it could be triggered by anything from a loose gas cap to a defective oxygen sensor or spark plug but could be more serious like a faulty catalytic converter or major engine problems.
This isn’t an end-all-be-all type scenario since a check engine light can come on for a few different reasons. But it’s usually one of the first things drivers notice when a car’s oxygen sensor is bad. Sometimes it’s nothing, and the light will turn off after running for a few minutes. If it’s flashing or stays on while you drive, it needs to be looked at.
2. Decrease in fuel efficiency
It’s important to keep track of how many gallons you fill up and how often you do so if it feels like you’re filling up your gas tank more often. This is usually fairly drastic and not just a few miles you might lose to sitting in traffic or behind red lights.
This is caused by the fuel-delivery and fuel-combustion systems not properly functioning due to oxygen sensor failures, and ultimately using more fuel than it needs to.
If you have an electronic odometer tracker and have noticed a steady decrease in efficiency and started paying more at the pump, this would be a good time to have a professional take a look. This is doubly important if your check engine light is on!
3. Engine skips, hesitates, or has trouble turning
This can be a frustrating and even scary experience that’s often attributed to advanced engine trouble. When one or more cylinders fail to fire properly, either due to ignition or fuel-related issues, the stuttering and jerking caused by the engine is typically obvious to the driver and passengers. If you’re feeling sputtering on mild jumping while driving or idling, get to a mechanic ASAP.
4. Exhaust releases black smoke or bad odor
These could of course be signs of other issues with the vehicle, but if you’re experiencing more than one of the problems listed above and can either see or smell something, it’s time to see a professional. It’s always recommended to get this taken care of as soon as possible but we all know life can happen and be unpredictable, so if you must wait, there are a few additional things you can do if you want to prolong that visit:
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1. Check the owner’s guide
While every vehicle at its base level is similar, there may be slight differences depending on make or model that could provide some options when experiencing maintenance issues.
Certain fuel recommendations, routine oil changes are standard things to look over. There could even be a “what does this vehicle do when an oxygen sensor is bad” section and how to get it fixed.
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2. Keep your vehicle well-maintained (or start now if you haven’t been!)
This is a great way to keep your vehicle road ready and in the best shape possible. If you don’t drive often it’s still recommended to get your vehicle checked at least once a year or every few thousand miles to replace things like filters and spark plugs. This is a good way that professionals often catch things that not everyone would notice.
3. Avoid low-grade fuel options
This likely won’t save your oxygen sensors, but may keep them around for a bit longer before they completely go out. While it has been mainly debunked that higher grade fuel will turn your vehicle into a brand new machine (see 2019 Car and Driver report) there are minimal advantages to user higher grades if you’re willing to pay a few extra cents per gallon.
When in doubt and your safety and others might be at stake, definitely go to a professional. Faulty oxygen sensors show up in different ways and can vary based on condition. A good rule to live by is that if you think something is wrong, it probably is. Even if you don’t experience shaking or see any release from the exhaust, it is always better to catch it early to prevent a hazardous ride and save some maintenance money!
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