BMW 3 (E46). Manual - part 64
positions.
The Double VANOS system allows full
variability of camshaft timing up to the
limits of the system. When the ECM
detects that the camshafts are in
optimum position, the solenoids are
modulated at approximately 100 - 220
Hz to maintain oil pressure on both
sides of the actuator pistons to
maintain timing.
In models with DME MS 43.0 (model
year 2001), the engine control module
(ECM) detects camshaft position before
the engine starts, thereby adjusting
camshaft timing immediately upon
start-up
Note:
BMW does not provide diagnostic
information or specifications for
the Double VANOS system.
VANOS system troubleshooting
and diagnostics is best
accomplished using a scan tool.
Diagnostic Trouble Codes (DTCs)
pertaining to the VANOS system
are listed in
Table a
. See also
OBD On Board Diagnostics
at
the back of this manual.
Elevated oil temperatures can
cause VANOS to deactivate. Oil
that is too thick (high viscosity)
may cause a DTC to be set in the
ECM. If VANOS is deactivated
(limp-home mode), there will be a
noticeable loss of power.
Table a. VANOS fault codes
BMW
code
P-code
Fault
description