• Home
  • Denver Auto Repair Services
    • Full Service Oil Change
    • Expert Mechanics
      • Expert Honda Mechanics
      • Expert Toyota Mechanics
      • Expert Subaru Mechanics
    • Automatic Transmission
    • Fuel System Cleaning
    • Radiator Flush Service
    • Wiper Blades
    • Air Filter
    • Cabin Air Filter
    • Gearbox Service
    • Brake Repair
    • Clutch Repair
    • CV Boots
    • Tune-Up
    • Steering & Suspension
    • Tires
  • Auto Diagnostic
  • Contact Us
    • About Us
  • Shop Specials
  • Testimonials
  • Blog
  • 303-691-2760

Express Car Care of Denver

"Denver's Best Auto Repair and Quick Lube"

  • Brake Service
  • Car Maintenance
    • Heating-Air Conditioning
    • Suspension
    • Transmission
    • Engine
    • Tires
  • Oil Change
  • Tips & Tricks

Oxygen Sensor

December 26, 2016 by Denver Express Car Care

Oxygen SensorMany people hear the term “Oxygen Sensor” and figure it must have something to do with sensing oxygen, but don’t really know much beyond that.  Let’s break it down:  your vehicle has an oxygen sensor in the exhaust manifold that measures how much unburned oxygen there is in the exhaust.  The sensor reports its findings to the engine control unit (ECU), which knows how much oxygen there should be in the exhaust.  Based on that information, the ECU will adjust the amount of fuel it sends to the engine.

This feedback and adjustment loop continues non-stop.  The goal is to have the optimal air to fuel ratio for performance, efficiency, and to lower harmful emissions.

There is a second oxygen sensor located in the exhaust pipe behind the catalytic converter.  It too measures the amount of oxygen in the exhaust, after it has been treated by the catalytic converter.  As the measurement is reported back to the ECU, the computer compares the oxygen levels before and after the catalytic converter to determine if the converter is still functioning properly.

So, 4-cylinder vehicles have two oxygen sensors.  V-6 and V-8 engines have four sensors, two for each bank of cylinders.  As you can imagine, the oxygen sensor lives and functions in a pretty hot environment so they will wear out over time.  Substances in the exhaust can also damage them leading to failure.  Outside elements like water and road salt can corrode an oxygen sensor and when the sensor goes bad it needs to be replaced.

You may be interested to know that oxygen sensors are often replaced needlessly.  When the oxygen sensor returns a measurement that is out of the specified range, it may trigger a trouble code in the ECU and the check engine light is illuminated.  Inexperienced do-it-yourselfers or part store employees may misinterpret a trouble code that reports an out of range sensor reading.  That could mean that the sensor is bad, but it could also mean that the sensor is accurately reporting a condition caused by some other malfunction.  A skilled diagnostician can sort this out and will only replace the oxygen sensor when it has truly gone bad.

When you have a check engine light come on and stay on, it’s good advice to have it checked out by a qualified service technician at Express Car Care.  The cause may be minor or quite significant, so it’s best to play it safe and let the professionals check it out.

Filed Under: Engine Tagged With: Oxygen Sensor

Express Car Care
4200 E. Evans Ave. Denver, CO (map)
Phone: (303) 691-2760
Located just southeast of the Colorado Light Rail station

Follow Us Today!

  • Facebook
  • RSS

Shop Hours

Monday: 8:00AM – 5:00PM
Tuesday: 8:00AM – 5:o0PM
Wednesday: 8:00AM – 5:00PM
Thursday: 8:00AM – 5:00PM
Friday: 8:00AM – 5:00PM
Saturday: Closed – A note from the owner
Sunday: Closed

Last car oil change time  – 5:00PM

Click for the BBB Business Review of this Auto Repair & Service in Denver CO

Recent Articles

Affordable Brake Pad Replacement in Denver: What You Need to Know

Affordable Brake Pad Replacement in Denver: What You Need to Know

What if your brakes failed today? You’re zooming down the highway, tap on the brake pedal, and nothing happens …  Scary, right? It rarely starts like that. Instead, when you hit the brakes, … [Read More...]

  • Is Your Car Ready for a Road Trip? Our Pre-Trip Inspection Checklist
  • How to Know If Your Car Needs Suspension Repair in Denver’s Bumpy Roads
  • Signs Your Car Battery Might Be Failing and Where to Replace It in Denver
  • Why Tire Rotation and Balancing Matter—Especially in Colorado’s Climate
  • How Often Should You Replace Your Car’s Timing Belt in Colorado?

Search Our Site

Brakes Service

Affordable Brake Pad Replacement in Denver: What You Need to Know

How to Prevent and Fix Uneven Brake Pad Wear

Brake Repair in Denver: 5 Warning Signs You Should Never Ignore

Oil Change

Why Regular Oil Changes Are Crucial for Denver Drivers

The Benefits of Using High-Quality Motor Oil for Your Engine

The Role of Regular Oil Filter Replacements

Suspension

How to Know If Your Car Needs Suspension Repair in Denver’s Bumpy Roads

A Guide To Understanding Bushings on a Car

Tips for Preventing Wear and Tear on Your Car’s Suspension

Transmision Service

Transmission Trouble? Common Signs and When to Visit Our Denver Shop

How to Prevent Common Issues with Automatic Transmissions

Understanding the Signs of Transmission Problems and How to Fix Them

Engine Service

Is Your Car Hesitating During Acceleration?

How to Troubleshoot a Rough Idling Engine

Signs Your Car’s Water Pump Might Be Failing

Auto Tips & Tricks

Check Engine Light On? Here’s What Denver Drivers Need to Know

The Importance of Regular Wheel Alignment for Tire Longevity

The Benefits of a Well-Maintained Suspension System

"Denvers Best Auto Repair and Quick Lube" - Copyright © 2025 - 4200 E. Evans Ave. Denver, CO 303-691-2760