I have a 01 Dakota 3.9 v6, i have re-done the entire exhaust and found 3 o2 sensor plug locations, not found 4th yet, (bought truck with zero o2 sensors in it) but driven it a good 50 miles since and keep deleting my o2 sensor codes for hope atleast 1 stays off but they ALL return heres the codes p0031 p0051 p0132 p0152 p0138 p0158 and p0442 i have checked relay and o2 sensor fuse in under hood fuse box they are good even replaced to double check any help would be great

 

P0031 O2 Sensor 1/1 Heater Circuit Low
P0051 O2 Sensor 2/1 Heater Circuit Low
P0132 O2 Sensor 1/1 Circuit Voltage High
P0152 2/1 O2 Sensor Shorted to Voltage
P0138 O2 Sensor 1/2 Circuit Voltage High
P0158 2/2 O2 Sensor Shorted to Voltage
P0442 Evap Leak Monitor Medium (0.040) Leak Detected
You need to find the short.

 

If you are missing sensors, I would imagine that would be a cause for codes. Search by VIN for O2 sensors on a mopar site. See what you come up with. They might have diagrams. https://www.moparpartsgiant.com/

 

Ok ill check plugs see for good power to them and see if anys low or higher than others

 

Ok ill look on there and see if i cant find my shy sensor plug haha

 

There will be 4 sensors and 4 wires. Three are on the transmission harness and one is on the engine harness. The O2's go on either end of each mini-cat.

If your truck has been swapped with a 97-00 federal Y pipe, then you'll have 2 "factory" bungs and likely a third put in by a welder and one likely hanging out somewhere.