Skip the auto shop - Our mechanics make house calls

Symptoms of a Bad or Failing Oxygen Sensor

oxygen sensor

Bad or Failing Oxygen Sensor Inspection

by a top-rated mechanic at your home or office

The oxygen sensor in your vehicle measures oxygen levels in the exhaust gases exiting the engine. This information is used by the Powertrain Control Module (PCM) to determine the correct air to fuel ratio for your engine in real time. The sensor is located in the exhaust system and allows the fuel injection and engine timing to work efficiently, which assists with emissions control. The oxygen sensor transmits the data to the vehicle’s PCM to maintain the optimal air to fuel ratio for your engine. A bad or failing oxygen sensor will have a negative impact on environmental emissions and engine performance, so there are a few things to watch out for before your oxygen sensor completely fails.

HAVE SYMPTOMS OF CAR TROUBLE?
Get an $80 diagnostic
by a top-rated mechanic at your home or office.

Get a quote · Book an Appointment · Our expert mechanics come to you.

1. Check Engine Light comes on

The first line of defense is the Check Engine Light. The Check Engine Light will illuminate if you have a bad or failing oxygen sensor. As soon as this light comes on, contact a professional automotive technician for a Check Engine Light inspection. This light can come on for many different reasons, so it is important to have it looked at by a professional who can correctly diagnose the exact cause. If you have high a mileage vehicle, there's a good chance it has a bad oxygen sensor that needs to be replaced.

2. Bad gas mileage

If the oxygen sensor is going bad, the fuel-delivery and fuel-combustion systems will be thrown off. If a bad oxygen sensor disrupts the air to fuel ratio mixture, or too much fuel is injected into the engine, your vehicle's gas mileage will be reduced. If you find that you are filling up your gas tank more often, keep a record of how many gallons you fill up with and how often. If it is more than normal, have a professional mechanic check out your oxygen sensor.

HAVE SYMPTOMS OF CAR TROUBLE?
Get your car fixed at your home or office.

Get a quote · Book an Appointment · Our expert mechanics come to you.

3. Rough engine idle and misfires

As your oxygen sensor is going bad you may notice your vehicle is running rough, misfiring or running irregularly while idling. Since the oxygen sensor output helps control engine timing, combustion intervals, and the air to fuel ratio, a bad sensor can disrupt these engine functions, causing a rough or irregular engine idle.

When to replace the sensor

If your vehicle was manufactured within the past 15 years, the oxygen sensor should be replaced every 60,000 to 90,000 miles. This sensor is a wear item and does fail over time. Replacement of a bad or failing oxygen sensor will reduce the level of emissions your vehicle puts into the atmosphere, while keeping your engine running smoothly and properly. As soon as you notice your Check Engine Light, poor gas mileage, or an irregular engine idle, book a service with YourMechanic to have your oxygen sensor replaced. This will ensure your vehicle is running smoothly and efficiently, and will help prolong the life of your engine.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Still not sure about your car's issue?
Diagnose your car
What kind of issue are you experiencing?
Brakes are squeaking
Car is not starting
Car is overheating
Car is shaking (vibrating)
Fluids are leaking
Heating and A/C
Smoke or steam is coming out of the car
Warning light is on
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

P0121 OBD-II Trouble Code: TPS "A" Circuit Range Performance Problem
P0121 code definition Throttle Pedal Position Sensor/Switch (TPS) A Circuit Range Performance Problem...
P0222 OBD-II Trouble Code: Throttle/Pedal Position Switch/Sensor B Circuit Low Input
P0222 code definition Throttle/Pedal Position Switch/Sensor B Circuit Low Input What the P0222...
How to Buy Fuel Treatments
Adding a fuel additive to your gas tank when you fill up is one way to clean vital engine parts of deposits, improve the performance of your engine,...


Related questions

Q: Wrench light comes on and chokes, loud grinding noise when I go slow

The two problems are not relates most likely. The grinding when hitting brakes is worn out pads and rotors. The stalling and wrench light will need to have the engine computer scanned and checked for stored codes. The codes will...

Q: Car won't let me accelerate.

Hello there, A continued oxygen sensor and voltage code is a sign there is still a problem with your 2002 Pontiac Firebird. You did not say if you replaced the oxygen sensor in question or not. I am going to...

Q: Car stalled out unexpectedly

Hello. This could happen for several reasons. Your car could have gone into a temporary limp mode because of transmission malfunction or because the battery and/or alternator has low voltage causing the car to stall. This problem should be addressed...