Elantra GLS Wagon L4-2.0L (2000)
Troubleshooting Procedures
TROUBLESHOOTING HINTS
1. If the heated oxygen sensor is defective abnormally, high emissions may occur.
2. If the heated oxygen sensor check has been normal, but the sensor output voltage is out of specification, check the following items related to the air
fuel ratio control system.
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Faulty injector.
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Air leaks in the intake manifold.
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Faulty mass air flow sensor, EVAP valve and engine coolant temperature sensor.
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Wiring connection problem.
3. When O2 sensor output voltage is maintained as following for above 50 sec.
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Upstream: 0.4 V - 0.6 V
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Downstream: 0.4 V - 0.5 V
Using Voltmeter
NOTE: If you release the accelerator pedal suddenly with the engine running about 4000 rpm, the fuel supply will be stopped for a while. When you
suddenly press the accelerator pedal, the voltage will reach 'B' range. Then, when you let the engine idle again, the voltage fluctuates between 'A' and 'B'
range. In this case, the O2 sensor can be determined as good.
