HO2S-1 and HO2S-2 On-Vehicle Inspection

HO2S Heater

1)Remove engine cover.

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 “1” and “2” at HO2S connector.
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: 2.5 to 5.0 Ω at 20 to 30 °C (68 to 86 °F)

HO2S-2: 2.5 to 5.0 Ω at 20 to 30 °C (68 to 86 °F)

[a]:	HO2S-1 connector (viewed from terminal side)
[b]:	HO2S-2 connector (viewed from terminal side)