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How Do I Repair My Car?
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How To Check
An Engine Oxygen Sensor?
How Do I Check An Engine Oxygen Sensor? (02 Sensor)
Car Repair Article - READ COMPLETELY BEFORE BEGINNING:
All engines run on an optimum fuel to air mixture called "stokiometric" which
means chemically balanced. This balanced fuel to air ratio is 14.7 to 1, 14.7
parts air to 1 part fuel. The oxygen sensor is created using the active chemical
such as zirconium, electrochemical (also known as Galvanic), infrared,
ultrasonic and very recently laser. When a lean mixture code is detected by you
or a technician the first tendency is to replace the oxygen sensor. The best way
to check the operation of the sensor is to run a simple test. No matter if your
engines oxygen sensor has one wire or four there is only one sensing wire that
feedbacks information to the PCM. To find this wire you will need a
car repair
manual. If a trouble code is present that pertains to an oxygen heater sensor
failure, replace the sensor to repair the problem. An oxygen sensor must be warm
before it will operate properly.
Warning: If a malfunction exists with related
components such as an
engine misfire or
engine vacuum leak do not perform this test. The
oxygen
sensor is designed to operate within a particular range, if this range is
exceeded the sensor will give the appearance that it has failed.
GM Oxygen Sensor - (appearances will vary)
Oxygen Sensor Test
Tools needed to perform these tests:
Voltmeter
- Step 1 - Once the oxygen sensor sensing wire has been
located connect a volt meter to the feedback wire and ground. Select the millivolt
operation on the meter.
- Step 2 - Next, start and
run the engine at idle until warm (about 15 minutes). Observe the voltmeter; it
should bounce slightly at whatever voltage the sensor is centered at (about 150 millivolts).
- Step 3 - Continue to observe
the meter and have a helper rap the throttle. The meter should drop for a split
second as the mixture leans out in the first milliseconds of the throttle bore
being opened. Then quickly rise for a spit second as the throttle closes and
the mixture richens. The volt meter should stabilize at the original operating voltage
when the engine returns to idle.
WARNING! Always have the vehicle under inspection on level
ground, in park with the emergency brake on. Always wear protective eyewear, gloves
and necessary clothing before inspection or work begins. Never crank an engine over
when anyone is near the battery or engine. Always have an operational fire extinguisher
close by, obey all first aid instructions in the event of an injury. Never stand
in front or behind a vehicle when starting or running. When engine is cranked over
keep hands and clothing away from rotating components.
How Do I Repair My Car?
/
How To Check
An Engine Oxygen Sensor?
Check Manufacturer Specific Oxygen
Sensor Questions and Answers
Additional Resources
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