They Haynes manual says it's the "Downstream Heated O2 Sensor Circuit low voltage"

Is that the O2 sensor after the cat? If it is, I won't worry about it for awhile, as it shouldn't hurt my mileage much... But since I'm leaving on a trip tomorrow after work, I'm going to need all the gas mileage I can get, so if it's not the one after the cat, I'll try and convince the dealership to fix it tomorrow... Help/advice/ideas welcome!

 

P0137 - HO2S Circuit Low Voltage B1S2

Yeah, that is the post cat sensor on 98+ trucks with 3 sensors. If this code were to pop up on '96-'97 trucks, this would be the down stream sensor directly ahead of the catalytic converter.

This will have no impact on fuel mileage if the sensor itself is going bad. I recommend clearing the code and seeing if it pops back up.

 

Yep, that's what I did.

Hopefully it clears itself up in a few days... My truck was running on 5 cylinders for awhile so the extra output from the cat might be fouling it up...

But that's what I needed to know! Thank you very much! Now I can go on my trip and not worry!

 

Well, the code still randomly comes on and off, so I'm guessing my sensor is buggered, lol.

Unless there's still excess junk being thrown out the cat... Which shouldn't be, since it's been awhile...

Would a buggered cat trip up the sensor?

 

Probably means that the sensor is in fact bad.

 

Understandable, I suppose, considering that it's been totally submerged, probably had a large amount of junk from 8000 missfires pass by...

 

Update: Apparently changing the spark plugs fixed the problem... I haven't had the SES light come on, or seen this code come through yet...

Unless I haven't done the right number of drive cycles for it to pop up...