P0040 MAZDA – HO2S11 Fuel Shift correction Fault

P0040 MAZDA Possible Symptoms

Engine Light ON (or Service Engine Soon Warning Light)

P0040 MAZDA Possible Causes

HO2 sensors harness is open or shorted,HO2 sensors circuit fuse,HO2 sensors circuit relay defective,HO2 sensors circuit connectors (wrong connection),Faulty Engine Control Module (ECM)

P0040 MAZDA Description

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