My Jeep turned on the check engine light this afternoon. Codes show P0137 and P0138 which are O2 sensor low voltage bank 1 sensor 2 and O2 sensor and O2 sensor high voltage bank 1 sensor 2 respectively.
I'm guessing this actually means that I have a shorted out O2 heater since the P0137 indicates test failed for short while off and P0138 indicates failure at high voltage while running. I looked under the Jeep today and didn't see any obviously damaged wires leading to the sensors, so I reset the codes. If the codes come back I'll look at replacing the faulty sensor without any more diagnostic since they're only $25 or so each.
Question I have is which one is which? I know that the sensor 1 is upstream and sensor 2 is downstream. I'm not sure about how bank 1 and bank 2 map to port and starboard. I'm guessing that bank 1 is on the passenger (starbord) side of the jeep since that's the side cylinder 1 is on the 3.8. Can anyone confirm this assumption?