Land Cruiser & LX470

Four heated oxygen sensors are used, one on each exhaust manifold, and one on each exhaust pipe, behind catalytic converter. On driver's side, heated oxygen sensor on exhaust manifold may be referred to as bank No. 1 sensor No. 1, and heated oxygen sensor on exhaust pipe behind catalytic converter may be referred to as bank No. 1 sensor No. 2. On passenger's side, heated oxygen sensor on exhaust manifold may be referred to as bank No. 2 sensor No. 1, and heated oxygen sensor on exhaust pipe behind catalytic converter may be referred to as bank No. 2 sensor No. 2.
To test the heater on the heated oxygen sensor, disconnect electrical connector from appropriate heated oxygen sensor and note heated oxygen sensor terminals. See Fig 1.
Using ohmmeter, check resistance between +B and HT terminals on electrical connector. See Fig 1. Replace heated oxygen sensor if resistance is not 11-16 ohms at 68°F (20°C).
If problem exists in heated oxygen sensor, heater or wiring circuit, a Diagnostic Trouble Code (DTC) may be stored in the Engine Control Module (ECM). For diagnosis of DTC, see appropriate TESTS W/CODES article.

Fig 1: Heater On Heated Oxygen Sensor Test (Land Cruiser & LX470)