Passat Wagon L4-2.0L (ABA) (1995)
Oxygen Sensor: Testing and Inspection
Oxygen Sensor Heating, Checking
OXYGEN SENSOR HEATING, CHECKING
Special tools, testers and auxiliary items
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VAG 1598/18 test box
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Multimeter (Fluke 83 or equivalent)
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VW 1594 connector test kit
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Wiring diagram
Test conditions
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HO2S relay OK
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Engine coolant temperature at least 80 °C (176 °F)
Test sequence
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Separate 4-pin HO2S harness connector.
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Check resistance of heating circuit at HO2S connector terminals 1 and 2.
Specification: max. 22 Ohms
If the specification is not attained:
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Replace HO2S G39.
If the specification is attained:
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Start engine and run at idle speed.
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Connect multimeter to measure voltage at HO2S connector terminals 1 and 2.
Specification: approx. battery positive voltage (B+)
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Switch ignition off.
If no voltage is present:
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Check wiring from HO2S connector terminals 1 and 2 to relay panel according to wiring diagram.