A/F Sensor Inspection

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)
- O2S11 (A/F sensor output current)
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 A/F sensor output current (PID: O2S11) is 0.25 mA or more while decelerating as shown in the figure.

Fig 1: Vehicle Speed, Engine Speed And A/F Sensor Output Current Graph
Courtesy of MAZDA MOTORS CORP.
- If not as specified, replace the A/F sensor. (See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION .)