Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Hello and welcome.
This code is for the bank1 sensor1 oqygen sensor insufficient switching.
If your scanner shows live sensor data, you would be able to see the reading are slow or not moving much at all.
That sensor is the most likely cause.
It is located in the exhaust manifold, accessed form under the hood.
need help on a 1999 Chevy K3500 pickup with a 7.4 L