The p0420 code is a generic code that indicates that the catalytic converter on the vehicle is not functioning properly. There are a number of reasons why this code could be triggered, including a clogged converter, a faulty oxygen sensor, or a problem with the engine's fuel mixture. In most cases, a mechanic will need to diagnose the problem in order to determine the best course of action.
You are here because you have a question about:
- error code 420
- error code po420
- catalytic converter error code
- p0420
1. Check the engine for leaks
- Remove the engine cover. Refer to Engine Cover Replacement - C6 Corvette.
- Locate the engine oil cooler. Refer to Engine Oil Cooler - C6 Corvette.
- Remove the engine oil cooler hose and check for leaks. Refer to Engine Oil Cooler - C6 Corvette.
- Check for leaks around the engine oil filler cap and around the engine oil drain plug. Refer to Engine Oil - C6 Corvette.
- If necessary, replace the engine oil cooler hose. Refer to Engine Oil Cooler - C6 Corvette.
2. Check the exhaust system for leaks
- Park the car in a safe area and turn the engine off.
- Inspect the exhaust system for any obvious leaks. If there are any, use a sealant or patch to fix them.
- Reattach the exhaust system to the car.
- Turn the engine on and listen for any leaks. If there are any, fix them and drive the car.
3. Check the oxygen sensor
- Disconnect the negative battery cable.
- Remove the airbag sensor.
- Remove the front airbag.
- Remove the upper airbag module.
- Remove the oxygen sensor.
- Clean the area around the sensor.
- Reinstall the sensor.
- Reconnect the electrical connectors.
- Reconnect the negative battery cable.
4. Check the catalytic converter
- Remove the hood and front bumper.
- Remove the four bolts securing the catalytic converter to the exhaust system.
- Move the converter to the side and remove it.
- Check the converter for cracks, tears, or other damage. If it's damaged, replace it.
- Clean the inside of the converter with a brush and solvent.
- Coat the converter with a new sealant.
- Replace the bolts, washers, and nuts.
5. Reset the computer
- Enter the manufacturer's setup utility
- Select the "reset" tab
- Select "advanced options"
- Select "memory"
- Delete all of the memory from the computer
- Reinstall the operating system
- Restore the factory settings
- Reinstall the software that caused the problem