Just had my father-in-law ask me to check his truck the other day because the CEL was on. I hooked up my Auterra and it turned out to be code P0138 - O2 Sensor Circuit High Voltage (Bank 1, Sensor 2). That code only comes on when the ECU picks up that the sensor volatge exceeded 1.5V and is now out of spec.

Well, I knew right away he needed a rear O2 sensor. So I took the VIN off the truck, went down to the Dodge dealer and got the sensor (new sensor had anti-seize on the threads, so someone on the Dodge engineering team has a brain between those two shoulders). I detached the connector and cut the wires off the old sensor, threw a 22mm socket on top of it with a 1/2" ratchet and the old sensor came right off (no air tools were needed). Put the new O2 sensor on with an adjustable wrench, reattached the wires, started the motor and tried to clear the CEL with the reader.

For whatever reason, it was being a stubborn SOB about letting go of it's CEL, so I double checked the sensor output on the Auterra and I knew it was working fine. Next a little persuasion was necessary so I just pulled the negative battery terminal for like 10 mins and no more CEL. I wish they were all that easy!