Code P0138 in my 2010 CTS 3L is intermittent, what caused that

Question

Code P0138 is intermittent, that is code comes on after couple of days off and again, what caused that

Answer 1

P0138 H02S circuit high voltage Bank 1 Sensor 2

Circuit high codes are disconnection or open circuit, when a H02S begins to fail its the heater internal  circuit that begins to develop problems, The fix is more than likely will be replace the H02S sensor

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