Most of the auto parts stores will put a scan tool on it for the code free of charge.. I bought my own since country living.. Once ya get the code plug it into youtube to see if it is an endeavor your willing and able to undertake.. This method has saved us a good bit of $$
If it isn't affecting the drivability it could be the O2 sensor, if there is a loss of power it may be the catalytic converter.
Also it probably has more than one catalytic converter and the code will tell you which bank is bad.
BTW...now is a good time to sell used cars because so many have tax refund money and are looking for a new ride.
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He already has the code. The auto part store won't tell him anything more.
If you drive older vehicles like I do it is handy to have one of the code reader dongles that will bluetooth to your smart phone. They are pretty darn cheap and the apps are free.
You may notice by the YT above I saw that..
Yeah, I saw that video when I was researching fixes for a similar problem with one of my vehicles.
P0420 just means that the front and rear 02 don't show the correct correlating values. This is usually due to a bad or dirty rear o2 sensor, but as others have said, it could be a few other things. If you don't have hesitation when there is a load on the engine, the converter is likely ok. I would reset the engine light and see how quick it comes back on. If there are no noticed drive-ability problems, you are ok to drive with the light on for a bit. Timmy's suggestion would probably fix the issue, I have done that on a few cars. I don't think the rear o2 will effect the mpg on an 08 GM, but I may be wrong. The correct way to diagnose the problem is to put a nice scanner on it and look at the front and rear 02 values.
I would unplug the battery as stated before, if that doesnt help, i would then have the O2 Sensors tested. If it pops back up after the power down, the only thing that could trigger the money light that fast is the O2 sensors.
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As my mechanic told me on my Toyota Tacoma, it's likely a bad connection on the O2 probes giving a false light unless your loosing power then it's the catalytic converter.
Get underneath the vehicle, unplug the probes before and after the catalytic converter and put the plug on and off a couple of times. Then as has been stated before, remove the battery cable, let it set for a bit and reattach the battery cable. That will reset the code.
If it's a hard code it will come back shortly. If it's a soft code by a bad connection, it will go away.
Get underneath the vehicle, unplug the probes before and after the catalytic converter and put the plug on and off a couple of times. Then as has been stated before, remove the battery cable, let it set for a bit and reattach the battery cable. That will reset the code.
If it's a hard code it will come back shortly. If it's a soft code by a bad connection, it will go away.
P0420, Catalyst Efficiency Bank 1. This is an exhaust emissions code that basically is saying the Bank 1 catalytic converter is not cleaning the exhaust to emissions standards. It doesn't mean it's clogged but possible, a gutted or non functioning converter would generate this code, clogged converters usually don't generate this code. This is a self diagnosing code, basically it takes a good working oxygen sensor and catalyst monitor (downstream or rear oxygen sensor) to generate this code, both sensors have to be working and when their signals would start mirroring each other that indicates the catalyst is failing. This code almost always is the result of a failed catalyst. The biggest reason for a failed catalyst other than age is from overheating, which is usually the result of excessive fueling ( ignition misfires or other rich fuel condition).
Bank 1 on the 3.6L is the rear or RH bank. This vehicle has 4 oxygen sensors, 2 of them are also known as Catalyst Monitors or the Downstream sensors, these are located behind or after the catalytic converter. The catalyst monitor is the sensor that triggers P0420 bank 1 & P0430 bank 2.
Bank 1 on the 3.6L is the rear or RH bank. This vehicle has 4 oxygen sensors, 2 of them are also known as Catalyst Monitors or the Downstream sensors, these are located behind or after the catalytic converter. The catalyst monitor is the sensor that triggers P0420 bank 1 & P0430 bank 2.
