only found 2 O2 sensors on exhaust. replaced both and still getting p0140 error code? Does canadian trucks only have 2 sensors?
Have 2001 GMC sierra with 5.3 engine and it was made canada. I have checked and on 2001 GMC Sierra 1500
You'll have 4 sensors total. 2 before (upstream) the catalytic converters and 2 after (downstream.) Another site said it was the MAF...Do some more homework.
This code sounds like it's indicating the second sensor on bank one.
apparently someone has emptied out your catylic converters. That's why you can't clear the code.