Oxygen Sensor: Testing and Inspection

CO Port Locations:

1. Remove exhaust sample port bolts for both banks of cylinders.

Exhaust Adapters:

2. Install BMW exhaust adapters 13 0 080 or equivalent.
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)

Fuel Pressure Regulator Locations:

5. Stop the engine and remove the fuel injector insulation cover.

Injection Component Survey:

6. Clamp vacuum hoses (12), at fuel pressure regulators (7), mounted on injector pipes (1 and 2).

Oxygen Sensor Connector Locations:

7. From under the vehicle, disconnect the oxygen sensors.

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 connectors.

CAUTION: Do not mix up the oxygen sensor connectors. Connector designated by red flag (cyl. 7-12).

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


10. If the correct response is not obtained:

^ Check for Digital Motor Electronic (DME) fault codes.
^ Replace the oxygen sensor(s) with known good unit and repeat the test.