When does the ECM set the P0420 code?
When does the ECM set the P0420 code?
When the ECM/PCM sees the downstream O2 sensor switching at or near the same rate as the upstream O2 sensor, it sets the P0420 code. What Does the P0420 Code Mean?
Where is the P0420 OBD2 trouble code stored?
The front O2 sensor measures the mixture, and it tells the engine control unit if the engine is running with a rich or lean mixture and adjusts it. The rear O2 sensor is just a diagnostic O2 sensor for this trouble code. If the rear O2 sensor is getting faulty values, the p0420 code will get stored in the engine control unit.
What does fault code P0420 mean on Mini Cooper?
Code p0420 cat eff. threshold exceeded means basically that the ECU has determined that the upstream and downstream O2 sensor readings have been too similar for too long so it reckons there must be nothing working between them… ie cat not doing its job, or not as good as it should be.
How does a P0420 readiness monitor test work?
During a P0420 readiness monitor test, the ECM will purposely and rapidly command a very rich and very lean mixture to force the downstream sensor to read the excess fuel or oxygen. Then it will stop the excessive air/fuel and watch the downstream sensor again, looking for a steady reading.
The front O2 sensor measures the mixture, and it tells the engine control unit if the engine is running with a rich or lean mixture and adjusts it. The rear O2 sensor is just a diagnostic O2 sensor for this trouble code. If the rear O2 sensor is getting faulty values, the p0420 code will get stored in the engine control unit.
What does P0420 code mean on catalytic converter?
This sensor checks the performance of the catalytic converter, making sure it scrubs the last vestiges of pollution from your exhaust. Oxygen sensors are only a part of a greater system, meaning if the p0420 code (or p0141, or p0135) is thrown, that doesn’t necessarily indicate the oxygen sensors need replacement.
How does the P0420 oxygen sensor simulator work?
The catalytic converter’s performance is measured by the secondary Oxygen sensor. If the output is less than 95% it throws the P0420 code. Graphing the output on an OBDII scanner shows an erratic curve with varying amplitude and frequency. To smoothen out the curve, an RC low pass filter circuit is used.
During a P0420 readiness monitor test, the ECM will purposely and rapidly command a very rich and very lean mixture to force the downstream sensor to read the excess fuel or oxygen. Then it will stop the excessive air/fuel and watch the downstream sensor again, looking for a steady reading.
