How To Read A Faulty Oxygen Sensor

By Author: Jason Dear
Total Articles: 11
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"I have had many questions on how to read a faulty oxygen sensor on a car. With a blaZt cable it's easy. Just plug in to the standard diagnostics port of your OBD or OBDII Nissan. Select O2 sensors on the data display (NB sensors for OBDII), click on display, start the car and wait for it to warm up.
A normal O2 sensor should oscillate from about 20% to 80% roughly once or twice a second when the engine is held at a constant RPM. What it's doing is detecting changes in O2 levels in the exhaust. When O2 levels go below 50% then the ECU automatically leans the fuel mix slightly causing less fuel burnt out the exhaust. As a consequence the exhaust fumes contain more oxygen and so the O2 sensor increases to above 50%. This causes the ECU to enrich the mixture making the O2 sensor go back to below 50% again. And so the cycle continues.
A faulty O2 sensor is sluggish or just stays on one reading. If you hold the engine at about 2000rpm and the engine temp is above 75degC (167 degF) and the O2 sensor oscillates back and forth less than once every 2 seconds then you have a sluggish O2 sensor. The engine self learn ...
... function will not adapt properly to this and your engine will slowly go out of tune and consume more petrol.
Some things that could cause sluggish O2 sensors are incorrect fuel, leaded fuel, fuel additives, age.
For blaZt cables that help to test the O2 sensors go to the blaZt website www.blazt.biz. All cables are affordable, workshop grade, and carry a 3 year warranty. You wont be disappointed.
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