Circuit Insulation Check

Disconnect connector from A/F sensor.
Using ohmmeter, check circuit insulation of A/F sensor. If faulty is found, replace A/F sensor.
- Between each heater terminal (1) and other than heater terminals (2).
  
  Fig 1: Checking Resistance Between Each Heater Terminal No. 1 & Heater Terminal
  Courtesy of SUZUKI OF AMERICA CORP.
- Between each terminal ((1), (2), (3) and (4)) of A/F sensor and A/F sensor body (5).
  
  Fig 2: Checking Resistance Between Sensor Terminals No. 1, 2, 3, 4 & Sensor Body
  Courtesy of SUZUKI OF AMERICA CORP.
Connect A/F sensor connector securely.