Can you pass smog with P0420 code?
Without a doubt, any tech will tell you to get a new Cat if you need to pass an emissions test. It will get rid of the P0420 which will cause an automatic fail anywhere emissions are tested using solely an OBD II test… As you have learned, the monitors have to be “READY” and a P0420 will cause them not to be ready.
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 O2 sensor to show the code po420?
Rich or lean mixtures can damage the catalytic converter, and when the catalytic converter is damaged/filled with fuel, the efficiency will be low, and the rear O2 sensor will see that and show the trigger the code Po420.
What does it mean if your OBD code is p04020?
It is important that the front and rear o2 sensors pass the Mode 6 tests. If they fail, false readings could potentially confuse the OBD-II software and trigger a false P04020 code. In most cases, the failing catalytic converter is not dangerous and poses no risk to the occupants of the car.
Can a damaged catalytic converter trigger the code po420?
Yes, they can, but not in the way you think. Rich or lean mixtures can damage the catalytic converter, and when the catalytic converter is damaged/filled with fuel, the efficiency will be low, and the rear O2 sensor will see that and show the trigger the code Po420.
What causes a car to have a code P0420?
The code P0420 can be caused by an engine problem that’s pouring too much fuel into the catalytic converter, excess fuel that the PCM can’t control, a vacuum leak that’s causing excess air to enter the catalytic converter, OR, a damaged catalytic converter What goes wrong with a cat converter? Cut-away of a typical catalytic converter
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?
Why do I need to resolve the P0300 code first?
For example, if you have these codes – P0300, P0420, P0171, then you’re going to want to tackle the P0300 Random Misfire code first (resolve it), and then tackle the P0420 code, etc. The reason for that is that the first code could be causing further DTCs to be set.
What to do if O2 sensor is bad?
If all that checks out, you’ll want to check the operation of the O2 sensor. To do that, you’ll need access to a scan tool or oscilloscope. Check that the waveform is pretty steady. If the reading fluctuates then the sensor is likely bad and will need to be replaced.