Oxygen Sensor: Testing and Inspection

TEST CONDITIONS
- engine oil temperature min. 80°C (176°F)
- radiator fan must have come on at least once
- all electrical consumers switched OFF (radiator fan and A/C must not be running while adjusting)
- pressure gauge not connected
- exhaust system must be free of leaks
- oxygen sensor control function OK

WORK SEQUENCE
- unplug harness connector from differential pressure regulator
- attach hamess adapter VW 1315/A1 between open harness connector and differential pressure regulator
- attach US 1119 to harness adapter VW 1315/A1
- switch US 1119 to DCA 200
- start engine and run at idle for minimum of two minutes

NOTE: After approx. two minutes, exhaust gas warms up oxygen sensor.
- read differential pressure regulator current displayed on US 1119
- current reading must fluctuate

If NO
- check current reading at 3,000 RPM

If still NOT OK
- replace oxygen sensor