I recently had my transmission pulled, completely overhauled and replaced. The rear shaft was also replaced with involved pulling the exhaust.

When I picked up the vehicle, I had the following OBDI2 codes:
P0030 - HO2S Bank1Sensor1 Heater Circuit
P0050 - HO2S Bank2Sensor1 Heater Circuit
P0134 - 02 Sensor CKT No Activitiy Bank1Sensor1
P0154 - 02 Sensor CKT No Activitiy Bank2Sensor1

I've already replaced (recently, ie last 20k miles) both post cat 02 sensors and one of the front 02 sensors just off the exhaust manifold which I believe is one of the Sensor1 sensors.

I have no idea where the heater circuit sensors are or how to check them.

Im also wondering if the shop who replaced the transmission/shaft could have left something unconnected which is causing these error codes.

Any advice would be appreciated.

Thx
Bob