What are the downstream sensors on an oxygen converter?
What are the downstream sensors on an oxygen converter?
On a scan tool, the downstream O2 sensors will usually be identified as Sensor 2 or 3. The PCM compares the readings of the upstream and downstream O2 sensors to see how well the converter is reducing pollutants in the exhaust.
Why does my downstream O2 sensor show Bad readings?
The downstream o2 sensor’s job is to monitor the catalytic converter. Most mechanics will often say it’s the o2 that is shot when it is actually the cat. When the cat is restricted, the downstream o2 will show bad readings. Understanding downstream and upstream, LTFT (long term fuel trim and STFT…
How does the PCM monitor the O2 converter?
The PCM compares the readings of the upstream and downstream O2 sensors to see how well the converter is reducing pollutants in the exhaust. When the engine is first started, the downstream O2 sensor’s output will mirror that of the upstream O2 sensor, and flip-flop back and forth between rich and lean.
How does the O2 sensor work on a car?
When the engine is first started, the downstream O2 sensor’s output will mirror that of the upstream O2 sensor, and flip-flop back and forth between rich and lean. Once the converter lights off, the downstream O2 sensor will settle down and “flat-line” at a steady voltage reading usually around 0.45 volts or so.
On a scan tool, the downstream O2 sensors will usually be identified as Sensor 2 or 3. The PCM compares the readings of the upstream and downstream O2 sensors to see how well the converter is reducing pollutants in the exhaust.
What happens when the O2 sensor drops off?
If the signal from the downstream O2 sensor continues to mirror that from the upstream oxygen sensor (s), it means converter efficiency has dropped off and the converter isn’t cleaning up the pollutants in the exhaust. This will set a fault code and turn on the Check Engine light when the OBD II catalyst monitor runs.
Where is the O2 sensor in the catalytic converter?
O2 sensors look like a plug sticking out of the exhaust system. They are normally positioned either in the catalytic converter or before and after it (with two separate sensors). Unplug the electrical wiring from the sensor. Squeeze the release tab and pull the plug out from the sensor housing.
The PCM compares the readings of the upstream and downstream O2 sensors to see how well the converter is reducing pollutants in the exhaust. When the engine is first started, the downstream O2 sensor’s output will mirror that of the upstream O2 sensor, and flip-flop back and forth between rich and lean.
