A common sign of a bad oxygen sensor (O2 sensor) is a decrease in fuel economy.

1. Oxygen
Sensors

2. • A common sign of a bad
oxygen sensor (O2 sensor) is a
decrease in fuel economy.

3. O2 sensors usually last
between 60,000 miles and
100,000 miles depending
upon the vehicle.

4. A decrease in fuel economy
does not automatically mean
your O2 sensor is bad, it's just
a symptom.
Before replacing an O2 sensor,
your vacuum hoses, spark
plugs, and ignition system
should be checked.

5. A vacuum hose could be leaking which can also
cause a bad oxygen sensor symptom even though
the sensor is functioning correctly.
A professional shop will use a diagnostic tree to
eliminate all other issues to ensure the suggested
repair is the right repair for your vehicle.
This will save you time and money.

6. Oxygen sensors work by
constantly measuring the
oxygen content inside the
exhaust manifold and
comparing it to the air outside
the engine.
A bad O2 sensor will usually
cause the check engine light
to illuminate.

7. A check engine light may also illuminate due to a
fouled plug, bad ignition switch, or a vacuum leak
among other problems.
All of these symptoms can return a bad O2 sensor
diagnostic code. Be safe have it checked at a
professional shop before you spend a fortune on
home repair.