Hi I have this code 0420 bank 1 coming up on my 05 tl, can anyone help with guiding me on what to do. Do I need to replace a sensor? And if so which exact one?? I can't pass smog and I'm over my due date on registration 😖😖

 

You can get that code from just letting your car sit running idle for an extended period of time.

Go to an auto parts store, or plug in your own OBDII scanner and clear the code to see if it returns.

Bank 1 is front by the way. If you needed to replace an oxygen sensor it would be located on the front catalytic converter just behind the radiator fan shroud; there's two per cat at the engine, a total of four oxygen sensors. The third cat under the car has no oxygen sensors.

If just wanting to pass inspection, clear it beforehand, you won't see it again immediately unless the oxygen sensor is completely bad.

 

Bank 1 is firewall side, same side a cylinder 1, not front.
P0420 cat bank 1, downstream sensor, after cat. Normally the code appears when the cat is below threshold, or bad, but the easiest is like above stated, have the code cleared and if it comes back, which it probably will, replace the sensor, then clear the code. If it comes back cat is bad, so either replace the cat or install spark plug non-foulers, illegal but will keep the code off. Aftermarket cats leave a lot to be desired as they don't last too long, at least from my experience.

This code has been appearing more and more as the cars get older and the cats deteriorate.

 

False.



Clearing it beforehand will still cause it to fail because once at smog, they will plug in OBDII and see that the monitors are not ready (aka know just cleared). They know this trick and will ask you to drive a cycle and come back (or just fail you again and make you pay to retest). Source: First hand experience

 

^ true story. California sucks

 

Well in terms of emissions anyway.. Have you SEEN the weather lately... All in all, it's fricking gorgeous and its mid-November

 

Not false.

I figured it was common knowledge to cycle your car after clearing the codes...the "not ready" is also a given when your CEL flashes five times after startup and after clearing codes. Obviously don't visit inspection until the CEL stops blinking five times...hurr durr.


Lead a horse to water...

 

When you are helping a new member out, rather than (to use your analogy) lead a horse halfway into the woods and expect them to find where the water is, why not give them all pertinent information to ensure they don't come back and say "but the monkey just told me to clear the code and go test!"


"I figured it was common knowledge" and "obvious" to you may not be obvious to everyone else.

 

Says the guy that every other post is a "lmgtfy," just eat it man. It's in the owner's manual...

You were wrong in calling my statement false, it wasn't. The advice was valid.

I can't think of another member that "welcomes" others as brashly as you do with your "clever" links.

 

can i have some jam with that please

 

^^^ Can I have some peace please.....guys, quit bickering-it's not pretty.

 

Yeah guys... squabble in private if you must - back on topic!

So I'm getting this code after getting P2628 first. All I've done was fill up with ARCO gas, ran one full tank through and have 3/4 of the 2nd in there (it was only $2.59/gallon for 91!!! can u blame me )
What's the deal here? Should I just wait until this tank is dry and fill with the gas I normally use? Or will adding an octane booster to raise the level help? Or is it something else and just coincidence that I used that brand gas?
I've attached pics from the OBD2 scanner

 

Can't believe it's the result of fuel, but I would replace the upstream sensor as that may be causing an incorrect fuel that causes problems with the cat and that is recognized by the downstream sensor.

 

well my fellow TL owners, it was in fact the fuel. After letting the tank run almost dry and filling with the brand I normally use, resetting the error using Pep Boy's tool, the check engine light has not come back on and there are no errors. Go Figure.

 

We'll see if it stays off as I still don't believe it's the fuel, never heard of just the type fuel of causing a P0420 code. Been wrong before, but may take a while before the code reappears, but I say it will return.

 

so... the first code P2628 has 4 pages of info (15 items) - what does all that info mean? is it good or bad?

I'll let you know if the check engine light comes back. What's the life of the cat? my car is a 2006...

 

First, I didn't realize there were 2 different posters.

P2628 Oxygen Sensor Pumping Current Trim Circuit High Bank 1 Sensor 1

Thought I'd copy the description:
The front air/fuel ratio (A/F) sensor (bank 1, sensor 1) is installed in the exhaust manifold and detects oxygen content in the exhaust gas. The front A/F sensor transmits output voltage to the powertrain control module (PCM). The PCM controls fuel injection duration by comparing the target air/fuel ratio with the front A/F sensor signal. The sensor includes the VS cell, the pump cell, the atmospheric reference cavity, the diffusion layer, and the heater, and it enables overall feedback control. The front A/F sensor (bank 1, sensor 1) has a built-in LABEL resistance to regulate the differences of the sensor characteristics. The PCM reads the resistance to regulate the difference properly. If the LABEL resistance (VLBLB 2 signal voltage) is a set value or more, the PCM detects a malfunction and stores a DTC.

Probably a bad sensor, so the easiest fix is to just replace the sensor.