I have a 2006 LR3 that I have enjoyed for many years in spite of the usual issues ALL LR's have!. Recently I had Engine Light ON for about a week and and after clearing all previous errors had the below scanned error codes remain:
P0036 Heated O2 Sensor Heater Control Circuit (Bank 1 Sensor 2)
P0056 Heated O2 Sensor Heater Control Circuit (Bank 2 Sensor 2)

I cleaned the connectors and checked for proper connection but still had both error codes. I thought it was somewhat odd two O2 sensors could be defective at same time - but went ahead and replaced the respective two sensor with BOSCH sensors and still get both same two error codes! Would really appreciate any help to figure out what else may be causing two O2 sensors to be faulting at same time?

Thanx- SAL!

 

Seems you have it covered. The service manual lists probable reasons and corrections for these codes. I only included P00036 as they are the same. I suppose you could recheck everything one more time before getting new sensors.

Possible problems:

Heated oxygen sensor heater circuit short circuit to ground,short circuit to power, open circuit, high resistance

Connector is disconnected, connector pin is backed out, connector pin corrosion

Heated oxygen sensor failure

Possible solutions:
Refer to the electrical circuit diagrams and check heated oxygen sensor heater circuit for short circuit to ground, short circuit to power, open circuit, high resistance

Inspect connectors for signs of water ingress, and pins for damage and/or corrosion

Clear the DTC and retest

Check and install new heated oxygen sensor as required


Sorry that I am not much help today.
Jeff

 

The only things that are common for both rear O2 sensor heating are the ECM, connector C2374, and fuse 11E in the engine compartment fuse box. It is a 15A fuse. I would check that and see if it is blown. It is possible one of the original O2s you replaced had a heating element that went bad and shorted, blowing the fuse. If that is fine and has 12V on it when the engine is first started cold then I would check the wiring starting with C2374 which is shown below