HO2S-1 and HO2S-2 On-Vehicle Inspection
Precautions: General safety (00)
HO2S Heater
1)Remove air cleaner assembly. 
2)Disconnect HO2S-1 or HO2S-2 connector with ignition “OFF”.
3)Using ohmmeter, measure resistance of HO2S connector (sensor side) of sensor heater between terminals “3” and “4” at HO2S connector.
If faulty condition is found, replace HO2S.
If faulty condition is found, replace HO2S.
NOTE:
Temperature of sensor affects resistance largely. Check that sensor heater is at correct temperature.
HO2S heater resistance
HO2S-1: 6.0 to 12.0 Ω at 20 °C (68 °F)
HO2S-2: 6.0 to 12.0 Ω at 20 °C (68 °F)