Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
OK, those two codes point to the Bank #2, Sensor #1 Oxygen sensor. This is located on the passenger side, before the catalytic converter. Your truck has four. One on each side before the converters and one on each side after the converters.
The reason I asked about the coolant leak, is because usually when I see the passenger front sensor fail, its because the intake gasket leaks, runs down the transmission bellhousing and drips on to the sensor or sensor connector.
I would start by replacing this sensor, and carefully look at the connector and surrounding areas for evedince of coolant leaking back there.
need help on a 1999 Chevy K3500 pickup with a 7.4 L