Oxygen Sensor
- Disconnect differential pressure regulator connector from side of regulator. Using Adapter (1315 A/1
), connect Multimeter (US 1119
) to differential pressure regulator and to the 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 no break in wiring is found, replace FICU. Reconnect O2 sensor (Green) wire. Start engine. Raise engine speed to approximately 3000 RPM for a few seconds.
- Differential pressure regulator current must return to original mA value and fluctuate approximately 1-3 mA in -10 mA to +10 mA range. If current does not return to original mA value or does not fluctuate, replace O2 sensor.
- To check O2 sensor heating element, disconnect O2 sensor heating element connector from harness connector. Connect multimeter between connector terminal No. 1 and No. 2. See Figure
.
- Turn ignition on. Multimeter should read 12 volts. If multimeter does not read as specified, repair break in wiring. Connect multimeter between terminals No. 1 and No. 2 of O2 sensor heating element connector. See Fig 1
.
- Multimeter should read 3-15 ohms. If multimeter does not read as specified, replace O2 sensor.
Courtesy of AUDI OF AMERICA, INC.