I am getting the following codes on my 2003 CTS
PO 141 Heated Oxygen Sensor Heater Performance Bank 1 Sensor 2
PO 161 Heated Oxygen Sensor Heater Performance Bank 2 Sensor 2
PO 0037 Heated Oxygen Sensor Heater Circuit Low Voltage Bank 1 Sensor 2
PO 0057 Heated Oxygen Sensor Heater Circuit Low Voltage Bank 1 Sensor 2

I have replaced all 4 oxygen sensors, the Oxygen Sensor Harness' and a new ECU.
Using a mutimeter I measured 12 Volts at the Sensor and when I checked the ground there was no ground. So I ran a wire from the sensor harness to ground, still same codes.
Has anyone run across this? I cannot pass emissions with these codes.
Car runs very well with no other problems.