P0420 - CATALYST SYSTEM EFFICIENCY BELOW THRESHOLD.
Description of DTC code P0420
Diagnostic code P0420 is very common and indicates that there is a fault or deficiency in the TWC catalyst, which aims to reduce polluting emissions; this is a vital component to reduce the environmental impact. This converter has a monitor, which allows measuring the effectiveness of this.
Symptoms of fault code P0420
- The Check Engine light is on.
- Generally, this code does not affect the normal performance of the engine, but you can perceive moments where the power of the engine is lost, and it is possible that you cannot travel due to the low acceleration.
Causes of OBD2 P0420
A code P0420 may have one or more of the following problems:
- The fuel used has a higher amount of lead.
- One of the sensors of the catalyst does not work correctly, giving very similar readings.
- The Engine Temperature Sensor is showing faults.
- There may be leaks in the exhaust pipe.
- Spark synchronization is delayed.
- Dirty air filter.
Possible solutions of the DTC code P0420
To fix the DTC code P0420 you can check the following components:
- Use an oscilloscope to verify the operation of one of the sensors of the catalyst, in case of finding problems in one of these, change it.
- Replace the TWC catalytic converter.
- Repair any leak in the exhaust pipe.
- Inspect the Downstream Oxygen Sensor HO2S, replace if necessary.