How to fix a P0420 code?
How to fix a P0420 code?
What repairs can fix the P0420 code?
- Replace muffler or repair leaks in the muffler.
- Replace exhaust manifold or repair leaks in the exhaust manifold.
- Replace exhaust pipe or repair exhaust pipe leaks.
- Replace catalytic converter (most common)
- Replace engine coolant temperature sensor.
- Replace front or rear oxygen sensor.
What does the P0420 code on the oxygen sensor mean?
Here’s how to modify your car’s oxygen sensor to get rid of a P0420 OBDII code, clear the check engine light and pass an emissions test. The P0420 code is thrown when the computer detects irregularities in the signal coming off of the secondary oxygen sensor.
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.
When does an O2 sensor set a trouble code?
If it’s not switching rapidly, the ECM will set an O2 sensor related trouble code If the upstream and downstream oxygens sensors are both switching from rich to lean, that’s the sign of a dead catalytic converter. An exhaust system leak really screws up the P0420 testing routing.
What happens if you leave P0420 on your car?
While P0420 does not pose a danger to the driver, it can cause driveability concerns such as a lack of power or poor acceleration if left unrepaired. It can also cause severe damage to other components of your vehicle if not addressed in a timely manner.
Where does the P0420 trouble code come from?
P0420 is triggered in the engine control module when there is a problem with the efficiency of the catalytic converter. The engine control unit uses two O2 sensors, one in the front of and one behind the catalytic converter to measure the efficiency of the catalytic converter.
What causes the P0420 oxygen sensor to read lean?
If the upstream and downstream oxygens sensors are both switching from rich to lean, that’s the sign of a dead catalytic converter. An exhaust system leak really screws up the P0420 testing routing. An exhaust leak near the upstream sensor can cause the downstream sensor to read a steady lean condition.
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.
If it’s not switching rapidly, the ECM will set an O2 sensor related trouble code If the upstream and downstream oxygens sensors are both switching from rich to lean, that’s the sign of a dead catalytic converter. An exhaust system leak really screws up the P0420 testing routing.
