P2238 after disconnecting battery

Disconnected battery to swap a bad stereo today. immediately after putting everything together and idling while I was programming the radio I kept throwing and clearing (scan gauge) an O2 sensor code (P2238). Battery voltage was running about 13.8v.

I cleared the code and drove it for a while to let the alternator do its thing. So far the code has not returned.

So I’m curious what the hive mind has to say. Was this likely just a temporary voltage issue or am I likely to see this return and find myself replacing a sensor?

{04, V6, 75K miles}

 

You can only wait and see what happens .

Might have been a temporary ground issue.

 

I've had this same code pop up with a battery that was almost bad (died a few months later), and again with a newer battery after using it to jump a friend's car. Both times the code eventually cleared on it's own.

I'm inclined to think it's a temporary voltage issue but see if it comes back

 

Seems the check engine light and P2238 code triggers if the truck is idling for a while. I don’t see it if I’m driving. AGM truck battery was recently installed and should be good, though I haven’t been running the truck much lately.

I think I’ll try to pull the upstream O2 sensor and check for resistance on a multi-meter. The sensor is original to this ‘04, but the problem began so soon after disconnecting the battery, I assumed they were related. Occam’s razor and whatnot.

 

Pulled and replaced the upstream air sensor (

$170 Denso 234-9003 Air Fuel Ratio Sensor

Denso 234-9003 for my V6 manual, NAPA online $180). Grabbed a multimeter and checked resistance across the black wires. Open loop. So I guess it was a bad sensor after all.

Learned:
a) the Denso sensor comes with a gasket and I didn’t need to buy the $6 gasket separately.
b) accessing the electrical connector on an ‘04 is a royal PITA. Wound up having to remove the rubber boot of the gear shifter from inside the truck and breaking a plastic clip to access the front of the connector.

Thanks for sharing your experiences and opinions.

 

Too late now. But I like to ask @turbodb when I have questions about stuff. A few others to. Dan is so thorough and likes to write a book about each repair. Lol! Definitely comes in handy.
Here was his write up on few things including the upstream sensor.
https://adventuretaco.com/chasing-the-p0171-engine-light/
Same part number as yours. Through the top of the shifter.
I had to replace mine but being an auto. It was easier.
Glad you got it done

 

For sure. Thanks! These photos would have been very helpful as I tried to pry the clip from its anchor point beneath the boot. My method was ultimately successful, but I reattached the clip with a zip tie and probably spent far more time swearing than someone who knew what the hell they were doing.