Checking Operation of VANOS

Interrogate fault memory of engine control unit. VANOS control unit connector is located behind oil filter and tied back on engine wiring harness.







Removing air guide for alternator.
Disconnect connector.







Connect Special Tool 61 2 050 on engine wiring harness and solenoid.







Switch on ignition.
Connect Special Tool 61 1 476 to one pin of two-pin connector of Special Tool 612 050.
Connect Special Tool 61 2 050 to vehicle earth.
Switching of solenoid must be heard and felt.
If solenoid does not react, refer to next step.







If solenoid does not react, Special Tool 61 2 050 must be connected on other pin of two-pin connector of Special Tool 611 476.
Again connect Special Tool 61 2 050 to vehicle earth.
Switching of solenoid must be heard and felt.







Dynamic Test:
Start and run engine at idle speed.
Again connect Special Tool 61 2 050 to vehicle earth.
Engine runs very erratically or dies.
If solenoid is not operated in this test, another test must be carried out with Special Tool 12 6 410.







Connect Special Tool 12 6 410 to connector of solenoid.
Connect red clip to battery positive connection point.
Connect black clip to vehicle earth.







CAUTION! Reversing terminals on Special Tool will destroy installed diode on VANOS solenoid valve. Solenoid valve remains serviceable but current spikes can give rise to faults in vehicle circuit.







Switching of solenoid must be heard and felt. If solenoid is now operated, check wiring from engine control unit to solenoid.
If solenoid is not operated, also refer to:
Electrical Wiring Diagrams.