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Home >> Mazda >> 1998 >> Protege ES L4-1839cc 1.8L DOHC >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Oxygen Sensor >> Testing and Inspection
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Oxygen Sensor: Testing and Inspection

OXYGEN SENSOR INSPECTION

Sensor Output Inspection

1. Connect the SSTs (NGS tester) to the data link connector-2.




2. Select the "PID/DATA MONITOR AND RECORD" function.
3. Select "FHO2S" and "RHO2S" on the NGS tester display. The NGS tester measures and shows the voltage.




Specification

4. If not as specified, inspect the following.
(1) Harness and connector between heated oxygen sensor and PCM
(2) On-board diagnostic system
(3) System inspection
(1) Intake manifold vacuum
(2) Fuel line pressure
5. If all the systems are okay, replace the heated oxygen sensor.

Heater Resistance Test

1. Disconnect the heated oxygen sensor connector.




2. Measure the resistance between heated oxygen sensor terminals D and C by using an ohmmeter.

Specification
- approximately 15.7 Ohm 20°C (68°F) (Front)
- approximately 15.7 Ohm 20°C (68°F) (Rear)

3. If not as specified, replace the heated oxygen sensor.
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