Code : P2A04 Oxygen sensor question

[mountie]

The P2A04 code keeps returning w/ CEL. Bank 2, Sensor 2..... There is a Bosh version, but I prefer the AC Delco? A bit more expensive, but I wonder if it's better to get the OEM part.
Also, I can assume if one is failing, I should go ahead an replace both bank 2 sides?

 

[Big Mama]

How often is the code returning? Any issues with the wires? I’ve changed them in pairs just bc I’m too lazy to get under it twice.

 

[OR VietVet]

Was there any other symptoms? No other performance problems? I had a downstream fail one time and I did all 4 sensors with Genuine GM. No problems since then.

 

[mountie]

Was there any other symptoms? No other performance problems? I had a downstream fail one time and I did all 4 sensors with Genuine GM. No problems since then.

No symptoms.... I cleared the code once... It returned within a day. I'm changing both 2 sensors. GM brand. Maybe all 4, considering the 172,000 on the clock.

 

[lyncht1967]

good plan..soak them all down with pb blaster while they are a bit warm after a drive and use a 7/8 or 22mm to turn each just a bit tighter..yes tighter...this will develop some hairline micro cracks in the threads allowing capillary action to pull in the pb. the next day things will go a lot easier

 

[lyncht1967]

and i run denso..have worked great...i believe they make em for GM

 

[mountie]

and i run denso..have worked great...i believe they make em for GM

I bought 2, and ordered the other 2. AC Delco.

 

[lyncht1967]

cool, you will be right as rain in no time...do a close visual inspection of all wire harnesses and wire routes for any chafing,corrosion, etc. while youre down there..

 

[OR VietVet]

Yes, get the penetrating fluid on there NOW. And every day till parts get there.

 

[mountie]

cool, you will be right as rain in no time...do a close visual inspection of all wire harnesses and wire routes for any chafing,corrosion, etc. while youre down there..

The bottom of my '05 is remarkably clean. I'm installing front Bilstien shocks, a Hellwig swaybar on the rear, and now, the 4 sensors, all at once. I always inspect the 'stuff' whenever the truck is on a lift.

 

[nonickatall]

It normalwise make no sene to change 4 oxygen sensors. The two in front of the cat are the relevant. They measure rest oxygen and give this values to the ecm to influence the injection amount.

The two behind the cats are only diagnose sensors to check, it the cats are working. Even when fail completely you have no bad running engine..

As well you can measure if the oxygen sensors working with a genuine multimeter.

That you have an o2 sensor error can be consequencial error, because if your combustion has problems for other reason, like air lecks in the intake, or a worn out maf, the o2 sensor can come to their measuring limit and you can have a code, even when they are good.

 

[mountie]

It normalwise make no sene to change 4 oxygen sensors. The two in front of the cat are the relevant. They measure rest oxygen and give this values to the ecm to influence the injection amount.

The two behind the cats are only diagnose sensors to check, it the cats are working. Even when fail completely you have no bad running engine..

As well you can measure if the oxygen sensors working with a genuine multimeter.

That you have an o2 sensor error can be consequencial error, because if your combustion has problems for other reason, like air lecks in the intake, or a worn out maf, the o2 sensor can come to their measuring limit and you can have a code, even when they are good.

I hear you....... I need such little repairs on my Yukon, and it has 172,000, the trouble code is sensor 2 bank 2, ..... I don't want to wait for another fault in the future. I am the type to 'service' what is 'old'. I believe in preventative maintenance. I appreciate your suggestions.

 

[lyncht1967]

love my bilsteins on all 4 corners and look forward to a hellwig rear sway as well...please let us know how that goes...

 

[mountie]

love my bilsteins on all 4 corners and look forward to a hellwig rear sway as well...please let us know how that goes...

I will...... Especially, when I discovered the factory rear sway bar is hollow!

 

[lyncht1967]

yes, the two rear are inconsequential to engine performance, but will throw a light when they decide to go lazy...at your mileage now I think its a good call to knock out all four as you intend..

 

[lyncht1967]

yeah i read it was hollow too on here somewhere and was flabbergasted as well
lol

 

[nonickatall]

I hear you....... I need such little repairs on my Yukon, and it has 172,000, the trouble code is sensor 2 bank 2, ..... I don't want to wait for another fault in the future. I am the type to 'service' what is 'old'. I believe in preventative maintenance. I appreciate your suggestions.

You are absolutely right, I see that the same way.

I repair on my car everything in time. If you let the things add up, someday the car is in a conditiom, where it is to expensive to put it back in service. If you keep repairing, you can drive the car, so to speak, into the eternity,

Expecially our trucks, which are very well made and where the main parts like, engine, transmission, axles, brakes are build to last long and to be serviced easy.

If I would have an oxygen error on oxigen sensor two, I would as well change both. i just wanted to say, that, if you have an oxygen sensor error from the main oxigen sensors and you are looking for the problem, then is not economical to change all four.

 

[nonickatall]

yeah i read it was hollow too on here somewhere and was flabbergasted as well
lol

Well we n Germany have a complete government which is hollow..

But that's a different story...

 

[mountie]

You are absolutely right, I see that the same way.

I repair on my car everything in time. If you let the things add up, someday the car is in a conditiom, where it is to expensive to put it back in service. If you keep repairing, you can drive the car, so to speak, into the eternity,

Expecially our trucks, which are very well made and where the main parts like, engine, transmission, axles, brakes are build to last long and to be serviced easy.

If I would have an oxygen error on oxigen sensor two, I would as well change both. i just wanted to say, that, if you have an oxygen sensor error from the main oxigen sensors and you are looking for the problem, then is not economical to change all four.

It's due to the age of all sensors.

 

[mwilson62000]

Must be something about 05 XL’s and about 170k on the clock. This past August mine had same code for same sensor. Just over 170k on mine. New ACDelcos all the way around for me as well.