Component Inspection

Fig. 41 Oxygen Sensor Test Connections:

1. Start engine and warm-up to normal operating temperature.
2. Connect the positive (+) probe of a voltmeter to terminal VF of the engine check connector, and the negative (-) probe to terminal E1. Fig. 41
3. Run engine at 2,500 rpm for 90 seconds to preheat oxygen sensor.

Fig. 94 Check Connector And Service Wire:

4. Using a service wire, connect terminals T and E1 of the check connector, Fig. 94, while maintaining engine speed at 2,500 rpm.
5. Observe the number of times the voltmeter oscillates in 10 seconds.
6. If 8 or more oscillations occur, the oxygen sensor is operating normally. If less than 8 oscillations occur, proceed with testing procedure.
7. Disconnect terminals T and E1 and maintain engine speed at 2,500 rpm.
8. Measure voltage betweem terminals VF and E1. If voltmeter reads 0 volts, extract diagnostic codes and follow appropriate testing procedures.
9. If voltmeter reads more than 0 volts, replace the main oxygen sensor.
10. After replacement, repeat steps 3 - 6 and note oscillations. If zero oscillations occur with new oxygen sensor, replace ECU.

OXYGEN SENSOR HEATER RESISTANCE (CA. ONLY):

Using an Ohmmeter, measure the resistance between terminal +B and HT.

Testing OS Heater Resistance:

Resistance (Cold): 5.1 - 6.3 ohms

If the heater element does not measure as specified, replace the Oxygen Sensor.