o2 sensor help
I own an 04 grand cherokee with the 4.0 motor.
I have two codes coming up with P0135 Generic o2 heater circuit (Bank 1, Sensor 1)
Also (Bank 2, Sensor 1)
I am trying to order o2 sensors, but not sure if they are down stream, upstream, right, left, etc..
If i could get some help on this it would be great!!