G 20 Van V6-262 4.3L VIN Z (1993)
Oxygen Sensor: Testing and Inspection
VISUAL INSPECTION
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Connectors and wires
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Housing and insulator for cracks/damage
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Sensor tip for silicone contamination (white powdery coating)
CAUTION Do NOT perform the following test for more than 2 minutes,
as this may cause damage to the catalytic converter.
PERFORMANCE TEST
Checks working range and response (speed).
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Warm engine
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Install DVOM between sensor and ground (2 volt D.C. range)
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"RUN" engine at steady cruise speed (about 2500 rpm)
Voltage should vary at least eight times in ten seconds between 0.2 and 0.8 volts (normal range).
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Drive system rich: The use of a properly adjusted propane flow-meter (J-26911) is industry standard.
Voltage should increase to at least 0.8 volts within two to three seconds.
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Drive system lean: Create a vacuum leak from a source that is not an control module input or output.
Voltage should drop to at least 0.3 volts within two to three seconds.
NOTE After each test the O2 sensor should return to normal operating range within two to three seconds.
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O2 Sensor should be replaced for failure to pass any of the tests above.
NOTE A CEC system that is operating excessively rich or lean will drive the 02 sensor to its maximum range and should be repaired first and not
diagnosed as a 02 sensor failure.
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Reconnect all hoses and electrical connectors. Clear all codes set and retrain idle.
HEATING ELEMENT (H20S only)
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Turn ignition "OFF". Disconnect electrical connector.
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Connect test light between harness terminals "A" and "B".
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Turn ignition "ON". Test light should be "ON".
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If test light is "OFF", connect test light to harness terminal "A" to ground. Light should be "ON" ensuring power circuit is operating correctly.
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Turn ignition "OFF".
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Using an ohmmeter, measure resistance between terminals A and B.
Resistance @ Specified Temperature
3.5 ohms @ 20°C (68°F)
14 ohms @ 350°C (662°F)
