My car also threw a o2 sensor code and I was able to get rid of it without having to replace the sensor.

 

Within range? Sorry, new to this.
AMP3D - how?

 

what bank is the code for?

 

Bank 1.

 

have you pulled the sensor to see if its a black and fouled? check wires to make sure there not melted to the exhaust.

 

heres a little writeup i found on a quick search.

It is important to remember that if your "Check Engine Light" illuminates and someone just simply reads a code of PO420, 421, 430 or 431 this does not necessarily mean the Catalytic Converter is bad! All that code says is either Converter operating below efficency or Converter operating below threshold. No where in the interpretation of that code does it say the converter is bad. Your vehicle may very well need a Catalytic Converter but to determine this, your mechanic or technician should perform proper engine diagnostics. Just reading a simple code is NOT considered performing diagnostics. The following material should give you a better understanding of what proper diagnostics consist of and how they should be performed. If after reading this material you still have questions please give us a call, 888-651-0770, and we will do all we can to help you solve the problem.


When your vehicle generates those emission codes it simply means that the converter is not able to function properly. Remember that the catalytic converter is at the very end of the emission diagnostic system, and a number of things can go wrong upstream of the converter that can cause. a PO420 (or PO430) MIL light illumination.

PO420 or PO430 CODE CATALYTIC CONVERTER FAILURE DIAGNOSTICS

Following is a list of procedures that should be accomplished before the final determination that a new catalytic converter is needed. These are known as diagnostic procedures and go far beyond someone just performing a simple code reading and then declaring a bad converter is present. That is not performing proper diagnostics! The following items will outline proper diagnostics in determining whether a converter is good or bad.

EXHAUST RELATED ERROR CODES

There are 711 possible PO generic DTC error codes. Only 7 of the 711 codes are exhaust related.

PO401: Insufficient EGR Flow

PO402: Exhaust Gas Recirculation (EGR) Excessive Flow Detected

PO410: Secondary Air Injection System Malfunction

PO420: Catalyst System Efficiency Below Threshold (Bank 1)

PO421: Warm-Up Catalyst Efficiency Below Threshold (Bank 1)

PO430: Catalyst System Efficiency Below Threshold (Bank 2)

PO431: Warm-Up Catalyst Efficiency Below Threshold (Bank 2)

THINGS TO ASK YOURSELF OR YOUR CUSTOMER

Have there been any driveability or performance issues with the vehicle, have there been any recent repairs or tune-up work performed, if so was the check engine light reset and were the codes recorded on previous repair orders.

Do not rely on scan tool data alone. In most applications, the customer will have the check engine light reset prior to repair. If the original cause of converter failure is intermittent, only the catalyst failure code may show up (masking the original reason for converter failure).

VEHICLE TEST

If possible, test-drive the vehicle and note any driveability issues that may indicate fuel or spark delivery problems such as hesitation, stumbling, spark knock or signs of misfire.
Idle smoothness. Check for any signs of surging or roughness, indicating misfire or improper fuel delivery.
Check the tailpipe, particularly immediately following start-up, for any smoke indicating too rich AFR (black smoke), water/antifreeze (white Smoke), or oil (blue smoke).
Listen to engine carefully for any signs of vacuum or exhaust manifold leaks.
Inspect intake system for signs of oil indicating excessive blow-by or cracks that may cause leaks.
Inspect spark plugs/wires and air filter.
Scan tool test.
Do not reset MIL light!!
Read the OBD-II readiness tests to ensure all tests have been completed. If the tests have not been completed, chances are the MIL was recently reset, possibly hiding intermittent problems.
Read trouble codes (if any) and inspect as necessary.
Read pending trouble codes (if any) and inspect as necessary.
With engine running and at operating temperature, read scan data list. This is typically a table listing all available sensors and outputs.
Look at Long Term Fuel Trims (LTFT). These show the amount (in %) the computer is modifying fuel delivery, based on the 02 sensor feedback. Positive numbers indicate the computer is adding fuel, negative numbers indicate the com puter is removing fuel. Large positive numbers (>10%) should be investigated further as they indicate the computer is adding more fuel than originally designed.
Look at the O2 sensor output signals. Sensor 1 is before the converter, Sensor 2 is behind the converter, Bank 1 and 2 are typically used in V-configuration where Bank 1 is on the side Cylinder 1 is located. Some inline 6 cylinder engines have Bank 1 as Cylinders 1-3 and Bank 2 as Cylinders 4-6. The sensors are usually abbreviated as O2S1B1 (O2 Sensor, Bank 1)
Sensor 1 output should be very active and oscillate rapidly from approximately 0 to less than 1 volt. If the signal tends to show high voltage with little fluctuation, excessive unburnt fuel is reaching the sensor. If Sensor 1 shows low or no voltage, the sensor could be defective, or there might be an exhaust leak in front of or immediately behind the sensor, or there could be a lack of fuel delivered to the combustion chamber. If the sensor does not respond to a rapid accelerator kickdown, chances are the sensor is defective. If it does respond, an exhaust leak or lack of fuel is indicated. (The preceding test must be done after the engine and exhaust system have been allowed to fully heat up.)




Sensor 2 should show a fairly steady signal. It is not critical what the signal is, only that it does not oscillate as frequently as the front. If the signal is above 250mV, the sensor is fine. If it is below, check for activity by rapid accelerator kick-down or by raising the engine speed to approximately 2000 rpm. Any movement indicates the sensor is fine.

 

Guitar: Mine came off by a simple mod I made. I replaced my factory air filter and with a k&n drop in airfilter. I then drilled a couple of holes into the factory airbox in specific spots. This caused my check engine light to turn off but then it came back on throwing a new code which was for the cat. This is also a cheap way to get more horsepower but don't expect too much. I would say 5-10 hp gain but that might be a little high. I would also reccomend getting some Maf sensor cleaner and cleaning the sensor. This is a very intricate process so do be very careful cuz you can do a lot of damage if your not.

Craby: Thanks for the write up. There are some things that I will definitely look at first before I will replace the cat. I appreciate that info. Ima have to get the exact and look up what I should do.

 

Alright, the code came back to me when I get out of the car after driving and smell a sort of burning...almost like plastic burning. My MPG is also decreasing (from what it was the first fill-up before the code). I wouldn't mind jacking it up (never done it, but don't suppose it is too difficult) and pulling out the sensor/whatever to make sure it isn't bad if I can try that.

 

That may not be a bad idea just to look at the whole underside of the car. I would recommend using a lift just because of the convenience. I'm not sure what the burning smell could be. I think if you were to talk to Massey he could steer you in the right direction.

 

I didn't want to start a new thread since I'm currently dealing with the same code, hope no one minds.

My MAF sensor was bad, also had p0420 code along with it. Replaced the MAF and the p0420 came back. A friend of mine checked out the car before and recommended a new PCV valve due to mileage, and a new PCV harness hose because it's cracked. Could this be causing my code? I don't want to replace the cat if I don't have to. For what it's worth, the car seems to be running fine, it doesn't bog down at all.