'97 Error Codes PO161, PO141

[GL1500]

Hey all, pretty new here. I've been reading up on the GMT400s here after picking up a rust free '97 Silverado. 5.7 Vortec, 225K miles. 4L60E, 3.73 limited slip. Trans was rebuilt with B&M kit. Intake gaskets have been replaced. 3" cat-back exhaust which sounds great with the windows rolled up (little loud for my tastes and probably my neighbors' as well). 3" lift rear and 2" drop spindles up front. All new brakes, wheels and tires (Cooper Discoverer 267/75/16 on Vision Warrior 375s). I have receipts for most the work listed above, totaling much more than I paid for the truck and quite frankly, I love it.

Mixed highway (75 mph)/rural driving yielded about 15 mpg (tracked via GPS as speedometer is ~15% off). Truck idles smooth and runs great.

This weekend the CES light came on so I stopped to have it read.

PO161 - heater circuit (bank 2, sensor 2)
PO141 - heater circuit (bank 1, sensor 1)

I can understand having an 02 sensor go bad and needing to replace it but when I have both codes, one from each bank it leads me to believe there's another issue. I haven't done much checking on the vehicle other than making sure fluid levels were ok (which they are). Truck still runs great.

What would trigger the reading (is it because the sensors are reading too lean or too rich?) and what items would cause such a condition? Since I don't have a code reader I'm plan to disconnect the battery for a while which I believe will reset the codes?

Just looking for a better understanding and direction as to where to look to fix this issue.

Thanks in advance for any help,
Steve

 

[GL1500]

***Update. I did not disconnect the battery to clear the codes, and the CES light has been on from Saturday to Wednesday. This morning (Thursday) I noticed the CES light was off. I wasn't aware the computer would reset by itself. Is that what happened or would the codes still be there if I checked?

 

[SAATR]

***Update. I did not disconnect the battery to clear the codes, and the CES light has been on from Saturday to Wednesday. This morning (Thursday) I noticed the CES light was off. I wasn't aware the computer would reset by itself. Is that what happened or would the codes still be there if I checked?

Yes, after a certain number of drive cycles the code will clear if the conditions that set it do not occur again. I can't remember how many cycles it is, but the vehicle has to be run at operating temp with certain other factors (load percentage, throttle percentage, closed loop, possibly speed, and others) without the fault condition reappearing.

Sent from my XT1585 using Tapatalk

 

[Rusty Nail]

Change the oil.

 

[GL1500]

Thanks for the replies. It's good to know about the computer resetting the codes and the CES light.

Regarding the oil, it was changed right before the PO put it away for the winter. It's full and looks new, like clean golden honey. Haven't tasted it.....

Again, thanks for the advise.

Steve