Oxygen Sensor: Testing and Inspection

CO Test Port Locations:

1. Remove the exhaust sample port bolts.

Exhaust Adapters:

2. Install BMW exhaust adapter 13 0 080 or equivalent at the ports.
3. Run the engine until normal operating temperature is attained (>160°F).
4. Record the exhaust sample readings. Nominal readings (approx. 0.7 ± 0.5)

Cover Removal:

5. Stop the engine and remove the injector cover.

Fuel Pressure Regulator Location:

6. Clamp the fuel pressure regulator vacuum hose, which is located at the rear of the injector rail.

Oxygen Sensor Connector Location:

7. Disconnect the oxygen sensor connector, which is located under the vehicle.

WARNING: The exhaust system will be extremely hot!

8. Restart the engine.

CO content should be noticeably higher than previously recorded.

9. With the engine running, reconnect the oxygen sensor connector.

CO content should return to previously recorded value (approx. 0.7 ± 0.5).

^ If the correct value is not obtained, verify that there are no fault codes in DME memory.
^ Replace the oxygen sensor.