Evaporative Emissions System: Testing and Inspection

Fig. 16 Evaporative Control System:

BMW has made many modifications to the evaporative control system. Check all applicable TSB's for latest EEC system update.
Check all vapor hoses and applicable wiring for cracking, restrictions and good connections. It is important, that the fuel cap is in good condition and does not leak.
This engine is equipped with a electronically controlled (by the ECU) EEC purge valve. It can be checked as follows:

- Disconnect the electrical connector at purge valve.
- Apply 12V positive to one terminal at purge valve. Ground the other terminal to the car body in fast intervals. The valve should be heard ("clicking") and felt as it opens and closes.
- If valve does not respond, replace and retest with new valve.
- Disconnect test wires and reconnect electrical connector.
- If EEC system still does not operate correctly, problem may exist in electronic control unit (ECU).