Originally Posted by maxxbear
I have a 2003 Tahoe with a 5.3 fuel flex I have replaced o2 sensor with a Denso sensor my check engin light still comes on its reading code po135heater circuit malfunction bank 1 sensor 1 what else needs to be done?
Check your fuse box in the engine compartment, there are two 15 amp fuses that go to the heated oxygen sensors. Check and see if 1 or both are blown. If so change that and reset codes. If blown that should work, it worked for me. Not many people check those fuses.