HO2S Inspection

WARNING: This page is about a different car, the 2014 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

Connect the M-MDS to the DLC-2.
Switch the ignition ON (engine on).
Warm up the engine to normal operating temperature.
Access the following PIDs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST .)
- VSS (Vehicle speed)
- RPM (Engine speed)
- O2S12 (HO2S output voltage)
Drive the vehicle and decelerate the engine speed by releasing the accelerator pedal fully when the engine speed is 3, 000 rpm or more.
Verify that the HO2S output voltage (PID: O2S12) changes as shown in the figure during deceleration. (It outputs 0.6 V or more once, then 0.3 V or less. )
- If not as specified, replace the HO2S. (See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION .)
  
  Fig 1: Vehicle Speed, Engine Speed And A/F Sensor Output Current Characteristic Graph
  Courtesy of MAZDA MOTORS CORP.