PO420 CODE ON CHEVY S10

The PO420 code is a generic code indicating a problem with the catalytic converter system efficiency below threshold. This issue can be caused by several factors, including:

1. A clogged or failing catalytic converter
2. An exhaust leak before the catalytic converter
3. A malfunctioning oxygen sensor
4. Fuel system issues, such as a clogged fuel injector
5. Engine misfire
6. A damaged or failing ignition system
7. A vacuum leak

Here are the steps you can take to diagnose and fix the issue:

1. Check the catalytic converter: If the converter is clogged, it may need to be replaced.
2. Examine the exhaust system for leaks: Leaks before the catalytic converter can reduce its efficiency. If a leak is found, it should be repaired.
3. Replace the oxygen sensor: If the oxygen sensor is malfunctioning, it can cause the engine to run too rich or too lean, which can affect the catalytic converter.
4. Check the fuel system: Clogged fuel injectors can cause a lean fuel mixture, which can harm the catalytic converter. Have the fuel system checked and cleaned as necessary.
5. Repair any engine misfires: An engine misfire can damage the catalytic converter over time. Fix the misfire and see if the code returns.
6. Check the ignition system: A faulty ignition system can cause a misfire and damage the catalytic converter. Have the ignition system checked and repaired as needed.
7. Find and fix any vacuum leaks: Vacuum leaks can cause a lean fuel mixture and damage the catalytic converter.

It's best to have a mechanic diagnose the problem and perform the necessary repairs, as some of these repairs can be complicated and require specialized tools.

Bad catalytic converter,live alone and drive.

Yes,did you change catalytic?

Pesky PO420 Codes - Eastern Catalytic

www.easterncatalytic.com/education/tech-tips/pesky-p0420-codes/

One of the most annoying is the persistent PO420 diagnostic code (Catalyst System ... not only shows its teeth when the catalytic converter is on the blink, but can also be ... Most, if not all, catalytic converter failures are caused by a problem or ...

P0420 Error Code: Catalyst System Efficiency Below ...

www.obd-codes.com/p0420

Repair information for the OBD-II trouble code P0420 - Catalyst System Efficiency ... If they have failed, it is likely due to something else that caused it to fail. ... the catalytic converter is broken or failed, it may be restricting the exhaust which will ...

explaining trouble codes po420 - po421 - Discount Catalytic ...

Hi, the usual cause is a worn out catalytic converter, but this code may also set due to a rich mixture. Check your tailpipe for soot or black film. If the pipe looks OK, replace the catalytic converter. If your converter is recently replaced or you have soot, please get back to me for a different plan of action.

For the lean condition I wound look for vacuum leaks.I you don`t find any then replace the o2 sensor for bank 1.As for the po420 if the exhaust system is not bent or damaged you will have to replace the catalytic converter.The catalytic converter has a longer warranty then the regular vehicle warranty itself so call the dealership and find out if the converter is still under warranty.The usual warranty I believe is around 80k.mileage years is 7 or 8 not positive.Hope this helps.Good luck.

PO420 code is for catalyst system efficiency below threshold (bank 1) Usually it means that it is time for a new catalytic converter on bank number 1. Cylinder bank number 1 is always the bank with the number 1 spark plug in it.

The p0300 code is a random missfire code sometimes caused by bad spark plugs and wires, if you have not done a tune up, it's time for one. now, the p0420 code is for catalyst efficiency below threshold, basically, your catalytic converter is bad and may need to be replaced. Sometimes repairing the random missfire can eventually clear the p0420 code. your car is not burning fuel properly, therefore the catalytic converter is getting dirty. Also, if you notice blue smoke coming out the tail pipe, then that's the cause for a failing catalytic converter as oil is getting to the combustion chamber and being burned off through the exhaust.

Not just a faulty catalytic converter will trigger this code. Many other issues can trigger this code.

• Leaded fuel was used where unleaded was called for
• An oxygen sensor is not reading (functioning) properly
• The engine coolant temperature sensor is not working properly
• Damaged or leaking exhaust manifold / catalytic converter / exhaust pipe
• Delayed spark timing
• The oxygen sensors in front and behind the converter are reporting too similar of readings

Possible solutions:

• Check for exhaust leaks at the manifold, pipes, catalytic converter.
• Replace Coolant Temperature Sensor
  
• Use a scope to diagnose the oxygen sensor operation (Tip: The oxygen sensor in front of the catalytic converter normally has a fluctuating waveform. The waveform of the sensor behind the converter should be more steady).
• Inspect the downstream heated oxygen sensor (HO2)
• Replace the catalytic converter
• Have timing adjusted
  

the problem is with the catalytic converter, there is a specific emission threshold that the exhaust must maintained. when it falls below this, you get this code. i just had to replace my converter for the same problem