Variable Camshaft Timing (Vanos)

The BMW-Vanos is a combined hydraulic and mechanical camshaft control unit, managed by the ECU. The double Vanos allows the engine to control valve timing continuously for both intake and exhaust camshafts. The electronically control of the Vanos positions is dependant on engine speed, load and temperature.

The function DEAVANOS is monitoring the correct mechanical function of the variable camshaft timing. The diagnosis carries out a continuous rationality check of the Vanos function. If a malfunction is detected, an error bit will be set and sent to the modules LAYDENWS, LAYDENWSAD or LAYDENWEKW for the inlet camshaft or LAYDANWS, LAYDANWSAD or LAYDANWEKW for the exhaust camshaft. These modules produce the final information for setting the corresponding DTC.

Two parameters are monitored for all camshafts, i.e. the adapted reference position and the control deviation. The diagnostic strategy for inlet and exhaust camshaft is identical: