Code : P2A04 Oxygen sensor question

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mountie

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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?
 

OR VietVet

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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.
 
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mountie

mountie

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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

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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
 
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mountie

mountie

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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.
 

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