Oxygen (O2) Sensor
- Disconnect differential pressure regulator connector from side of regulator. Using Adapter (VW-1315-A/1), connect Multimeter (US-1119) to differential pressure regulator and connector removed from regulator.
- Set multimeter to 200-mA DC scale. Disconnect O2 sensor connector. Start engine and let idle. Note reading on multimeter. Ground male end of O2 sensor connector.
- Observe multimeter. Current should increase from 9 mA to 11 mA after 15 seconds. If multimeter reading is not as specified, check wiring between FICU and O2 sensor harness connector.
- If wiring is okay, replace FICU. Connect O2 sensor, and start engine. Raise engine speed to about 3000 RPM for a few seconds.
- Differential pressure regulator current must return to original mA value and fluctuate about 1-3 mA in -10 - 10 mA range. If current does not return to original mA value or does not fluctuate, replace O2 sensor.