Application Guide
What is the difference between Wideband and Air Fuel 
ratio sensors? 
A Bosch Premium Oxygen Sensor will tell you if your engine is 
running rich or lean. A Bosch Wideband Oxygen Sensor is able 
to measure the precise amount of oxygen in the exhaust to tell 
your ECU exactly how much fuel your engine needs to operate 
at optimal combustion. Technical advances like the Bosch 
Wideband Oxygen Sensor have allowed vehicle manufacturers 
to increase fuel economy as well as engine performance.
Trust the experience of Bosch
Bosch invented the automotive oxygen sensor and has manufactured 400 million 
sensors since 1976. Today it is the world’s largest producer of oxygen sensors and 
currently supplies them to virtually all vehicle manufacturers in the world.
Did You Know? 
Bosch Oxygen Sensors are an exclusive NASCAR Performance® product.
When to replace an oxygen sensor
Exposure to carbon, soot, harmful gases, antifreeze, 
chemicals, and thermal and physical shock will shorten the 
life of an oxygen sensor. A worn sensor can result in reduced 
gas mileage, poor engine 
performance, and/or 
emissions test failure.
That’s why checking, and 
if needed, replacing a 
worn-out oxygen sensor 
with a Bosch Premium 
Oxygen Sensor is an 
important part of every 
routine tune-up.
Side effects of a worn-out oxygen sensor Benefits of replacing an oxygen sensor
Wastes fuel Saves money in fuel costs
Can cause engine performance problems, such as surging 
and hesitating
Improves engine performance
Is the number one cause of excessive harmful exhaust 
emissions
Dramatically reduces harmful emissions
Accelerates catalytic converter damage Prevents premature failure of the catalytic converter
Why do i need to replace my oxygen sensor?
It is important to replace your oxygen sensors at the 
manufacturer’s suggested intervals or upon failure, whichever 
occurs first. Prompt replacement will save you money in the 
long term. Here’s how: 
 f If an oxygen sensor is not functioning properly, it may not 
accurately measure the amount of fuel being consumed and 
cannot efficiently regulate the consumption. This results in 
lower MPG. 
 f A faulty oxygen sensor can cause your catalytic converter 
to fail prematurely. The catalytic converter is responsible 
for removing the harmful emissions from your exhaust gas. 
Replacing a catalytic converter can cost thousands of 
dollars, significantly more than most oxygen sensor 
replacements.
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©2014 Robert Bosch LLC, USA. All rights reserved. BOSCH is a registered trademark of Robert Bosch GmbH and/or its affiliated entities.


