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# AIR FUEL RATIO SENSOR (for Sensor 1) > ON-VEHICLE INSPECTION

## for Preparation Click here

1. INSPECT AIR FUEL RATIO SENSOR (for Sensor 1)

1. Using an ohmmeter, measure the resistance between the terminals.

   Standard resistance:

     Tester Connection | Specified Condition
     1 (HT) - 2 (+B) | 1.8 to 3.4 Ω at 20°C (68°F)
     1 (HT) - 4 (AF-) | 10 kΩ or higher

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

2. INSPECT AIR FUEL RATIO COMPENSATION SYSTEM

1. Measure the voltage between terminals of the ECM.

   Standard voltage:

     Tester Connection | Condition | Specified Condition
     E16-22 (A1A+) - E17-1 (E1) | Ignition switch ON | 3.3 V
     E16-22 (A1A+) - E17-1 (E1) | Ignition switch ON | 3.0 V
     E16-22 (A1A+) - E17-1 (E1) | Ignition switch ON | 3.3 V
     E16-22 (A1A+) - E17-1 (E1) | Ignition switch ON | 3.0 V

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

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

1. Connect the intelligent tester to the DLC3.

1. Select "DATA MONITOR" - "A/FS B1 S1", "A/FS B2 S1" and "O2S B1 S2" to display the monitor.

1. Warm up the A/F sensor with the engine speed at 2,500 rpm for approximately 2 minutes.

1. Keep the engine speed at 2,500 rpm and confirm that the displays of "A/FS B1S1" and "A/FS B2 S1" are similar to the illustration.

   HINT:
   1. The illustration differs from the real display.
   2. Only the intelligent tester displays the waveform of the A/F sensor.

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