Air-Fuel Ratio (A/F) Sensor

INSPECT AIR-FUEL RATIO COMPENSATION SYSTEM










a. Measure voltage between terminals of the engine ECM.

CAUTION: Connect test leads from the back side of the connector with the ECM connected.

HINT: Voltage between terminals of the engine ECM is kept constant regardless of the voltage of A/F sensor.

b. Connect the hand-held tester to the DLC3.
c. Select "DATA MONITOR" - "A/FS B1 S1", "A/FS B2 S1" and "O2S B1 S2" to display the monitor.
d. Warm up the A/F sensor with the engine speed at 2,500 rpm for approx. 2 minutes.







e. Keep the engine speed at 2,500 rpm and confirm that the displays of "A/FS B1 S1" and "A/FS B2 S1" are as shown in the illustration.

CAUTION: The illustration differs from the real display. Only hand-held tester displays the waveform of A/F sensor.

f. Confirm that the display of "O2S B1 S2" changes between 0 V to 1 V with the engine speed at 2,500 rpm.











AIR FUEL RATIO SENSOR
Using an ohmmeter, measure the resistance between the terminals.

If the resistance is not as specified, replace the sensor.