P2099

[scth]

700 miles into driving from California to Florida. Got a CEL. Reader says P2099. Running rich on bank 2 post catalytic. Trying to see if we can keep the schedule or if stopping at a dealer would be better. ‘16 XL Denali - 37,000 miles. All dealers closed right now. Anyone seen this one? O2 sensor on right side looks fine, not loose, no wire chafing that I can see. Any suggestions?

Thanks!

 

[kbuskill]

700 miles into driving from California to Florida. Got a CEL. Reader says P2099. Running rich on bank 2 post catalytic. Trying to see if we can keep the schedule or if stopping at a dealer would be better. ‘16 XL Denali - 37,000 miles. All dealers closed right now. Anyone seen this one? O2 sensor on right side looks fine, not loose, no wire chafing that I can see. Any suggestions?

Thanks!

Not sure but 2016 should be in the K2 section of the forum...

@NathanJax can you fix it for him.

 

[wjburken]

Are you seeing any difference in engine performance?

 

[scth]

Are you seeing any difference in engine performance?

No change. Smooth idle. Haven’t noticed a change in mpg.
My theory is the high temps +110° F and altitude +4,000’ is just too much for the computer to keep up with? Not trimming the fuel enough so it shows rich? Not sure. I’m a wanna be mechanic.

Thanks!

 

[scth]

OK - felt ballsy. Erased the CEL. Drove another 700 miles, no issues. Temps today a minimum of 13 degrees cooler and elevation dropped 2,000’ so maybe my theory was close to the truth. Who knows. Thanks.