1998 GMC Sierra 1500 service engine soon. Getting P0141 and P0161 error. I have no idea what this means or where these sensors may be located. Any HELP.

P0141 -- O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 2)

P0161 -- O2 Sensor Heater Circuit Malfunction (Bank 2 Sensor 2)

I don't have a manual right infront of me, but I believe that since you have both sensors with a heater code, you may have a fuse blown in the underhood fuse box that provides 12 volts to the Oxygen sensor heating elements. Your O2 sensors are screwed into your exhaust pipes just after the exhaust manifolds and after the catalytic converters. If the sensors were totally disconnected, then the computer would have more codes. Hope this gives you some ideas. Check out www.troublecodes.net for more information about your OBD2 codes and their meanings. Good Luck -Chris