What is upstream and downstream sensor?
The upstream sensor monitors the level of pollutants in the engine’s exhaust and sends this information to the ECU that continuously adjusts the air-fuel ratio. The downstream sensor measures the level of pollutants passing through the catalytic 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.
What should voltage be on zirconia upstream oxygen sensor?
A traditional zirconia upstream oxygen sensor produces a voltage signal that continuously switches back and forth. The reading gives the PCM an idea of the engine’s air/fuel mixture. A value above 0.45 volts indicates a rich condition, while a reading below 0.45 volts indicates a lean condition.
What does high voltage mean on O2 sensor?
The high voltage condition from the O2 sensor is indicating a lack of oxygen in the exhaust or other related problems, such as a leaking fuel injector or a broken up catalyst inside. Need help with a P0138 code?
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.
A traditional zirconia upstream oxygen sensor produces a voltage signal that continuously switches back and forth. The reading gives the PCM an idea of the engine’s air/fuel mixture. A value above 0.45 volts indicates a rich condition, while a reading below 0.45 volts indicates a lean condition.
The high voltage condition from the O2 sensor is indicating a lack of oxygen in the exhaust or other related problems, such as a leaking fuel injector or a broken up catalyst inside. Need help with a P0138 code?
Can a downstream O2 sensor affect engine performance?
Seems as though the downstream sensor has minimal to no affect on engine performance. Definitely not running in limp mode.