Oxygen Sensor

Warm engine to normal operating temperature. Connect voltmeter to check connector. See CHECK CONNECTOR LOCATION table for location of connector.
Ensure positive probe is connected O "Ox" terminal and negative probe is connected to terminal "E". Start and race engine to 2500 RPM for about 90 seconds. Maintain engine speed at 2500 RPM and ensure voltmeter needle fluctuates 8 times or more in 10 seconds within 0 - 7 volts. If voltmeter fluctuates as indicated, oxygen sensor is okay.
If not, inspect hoses and wiring of fuel feedback control system and air suction system. See TOYOTA AIR SUCTION article in this section. If no problem is found, replace oxygen sensor.

CHECK CONNECTOR LOCATION

Application

Location

Corolla FWD

Right Fender Apron Below EBCV

Corolla RWD & Tercel Wagon

Right Fender Apron Below Wiper Motor

Pickup,4Runner

⁽¹⁾ Near No. 2 Relay Block

Tercel Sedan

Near Clutch reservoir tank

⁽¹⁾	See Figure.

Fig 1: Pickup Oxygen Sensor Testing (Typical)