The modern vehicle has 2 lambda sensors fitted, one before (Bank 1) and one after (Bank 2) the Catalytic Converter. The Bank 1 Lambda Sensor of your Audi A6 checks the air/fuel ratio and regulates the mix via the ECU to protect the catalytic converter and to reduce the emissions to the atmosphere. The Bank 2 Lambda sensor of your Audi A6 checks the resulting emissions after the process of the fumes through the Catalytic Converter. Both Lambda Sensors in your vehicle therefore have different tasks and result with different issues. It is necessary before ordering to know if it is the pre-cat or post-cat Audi A6 Lambda sensor you require.

Select "Lambda Senor" in the Refine Products on the left hand column, to reduce the selection of sensors listed for your Audi A6.