Resistance Inspection (A/F sensor heater)

WARNING: This page is about a different car, the 2009 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.

Disconnect the A/F sensor connector.
Measure the resistance between A/F sensor terminals 2 and 4.
- If it is not within the specification, replace the A/F sensor. See AIR FUEL RATIO (A/F) SENSOR REMOVAL/INSTALLATION [MZI-3.7] .
  A/F sensor heater resistance
  
  1-10 ohms
  
  Fig 1: Identifying A/F Sensor Connector
  Courtesy of MAZDA MOTORS CORP.