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Why should you change an oxygen sensor?
It is critical that oxygen sensors are replaced at the
suggested intervals provided by vehicle manufacturers
before the sensor fails. Following the
recommendations will prevent long term damage to a
vehicle’s engine, reduce harmful carbon dioxide (CO
2
)
emissions and save money when refueling your vehicle.
An oxygen sensor’s service life varies: oxygen sensors
with 1 – 2 wires have a typical service life between
30,000 – 50,000 miles; while 3 – 5 wire sensors have a
life span of up to 100,000 miles. Checking and
replacing worn out oxygen sensors has become a
critical part of regular vehicle maintenance.
A worn out oxygen sensor can cause
f Engine performance issues
f Lower miles per gallon fuel efficiency
f Excessive harmful exhaust emissions
f Catalytic converter damage
Replacing a worn oxygen sensor
f Improves engine performance
f Reduces harmful emissions
f Optimizes fuel delivery for maximum
miles per gallon
f Prevents catalytic converter failure
14060253 V3
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How to diagnose
State of oxygen sensor:
Dark brown discoloration.
Possible cause:
Air-fuel mixture too rich.
Measure:
Check the fuel pressure.
Replace the oxygen sensor.
State of oxygen sensor:
Blackened, with oily contamination.
Possible cause:
Excessive oil consumption.
Measure:
Check the valve guides and seals,
which may be worn. Replace the
oxygen sensor.
State of oxygen sensor:
Greenish, grainy discoloration.
Possible cause:
Antifreeze has escaped and entered the
combustion chamber.
Measure:
Replace the oxygen sensor. Check the
engine block, cylinder head, intake
manifold and head gasket for wear
and cracks.
State of oxygen sensor:
Reddish or white discoloration.
Possible cause:
Fuel additives in the gasoline.
Measure:
Do not use fuel additives.
Replace the oxygen sensor.
State of oxygen sensor:
The molded cable tubing is damaged.
Possible cause:
Impact by stone chippings.
Measure:
Replace the oxygen sensor.
State of oxygen sensor:
Broken cable.
Possible cause:
Excessive cable tension.
Measure:
Replace the oxygen sensor.
Route the new cable without tension.
Oxygen sensors are important
engine components –
indispensable for reliable
engine function and correct
emission values. But the
perfect functioning of oxygen
sensors can be jeopardized by
many factors:
f Environmental influences, such as salt and dirt
f Large temperature fluctuations
f Poor-quality fuel
f Soot and oil residues in the exhaust gas