p0036 & 54 on '07 Buick-R. Replaced 02 sensor upstream. Engine Light is on - what's the problem?

Question

P0036 and P0054 on 2007 Buick Rendevous.  Mechanic said I needed 02 sensor (upstream) which was replaced.  Next day Service Engine Light came back on.  What could be the problem?

Answer 1

P0036 H02S heater control circuit  Bank 1 Sensor 2

P0054 H02S heater resistance Bank 1 sensor 2

This code that is set is for the downstream 02 sensor , Sensor 1 are upstream 02 sensor these are the engine management sensor, Sensor 2 are the Downstream 02 sensor these are the catalytic monitor sensors. What you have set are the down stream 02 sensor on Bank 1