i believe P1135 relates to AFR heater on rear bank sensor (by firewall), not by the front of car.
P0135 is Heated Oxygen Sensor Circuit - Bank 1 Sensor 1.
P0135 is Heated Oxygen Sensor Circuit - Bank 1 Sensor 1.
Personally, I'd replace them in pairs because you'll soon get a P1155 or even a P1153 for the one on the front bank (closest to the radiator).glen-
i replaced the one in front of the radiator...should i put the old one back in and put the new one in that spot?