P0040 AUDI – HO2S Bank 1 and 2 Sensor 1 Signal Wires Swapped

P0040 AUDI Possible Symptoms

Engine Light ON (or Service Engine Soon Warning Light)

P0040 AUDI Possible Causes

HO2S Bank 1 and 2 Sensor 1 harness is open or shorted,HO2S Bank 1 and 2 Sensor 1 circuit connectors (wrong connection),Faulty Engine Control Module (ECM)

P0040 AUDI Description

The heated oxygen sensor (HO2S) monitor determines if the HO2S signal response for a fuel shift corresponds to the correct engine bank.