HO2S Heater Resistance Inspection

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 HO2S connector.
Measure the HO2S resistance between terminals C and D.
- If not as specified, replace the HO2S. (See HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION [L5] .)
  HO2S heater resistance
  
  2-50 ohms
  
  Fig 1: Identifying HO2S Connector Terminals
  Courtesy of MAZDA MOTORS CORP.