1 Series E87 118i (N46) 5-door
On the E60, E81, E87, E90, E91, E92, E93 the electronic immobiliser is controlled by the CAS control unit.
If the identification data are correct, the EWS or CAS control unit activates the starter via a relay which is located
in the control unit.
At the same time, the EWS or CAS control unit sends the DME control unit an encoded release signal (rolling
code) to start the engine. The DME control unit only enables the start if a correct release signal has been
received from the EWS or CAS control unit.
The following faults are stored in the DME control unit:
•
Missing or disturbed release signal from the EWS control unit
•
Rolling code from the EWS or CAS control unit does not tally with the rolling code computed by the DME
control unit.
If a fault is detected, the engine start is blocked.
•
4th generation electronic immobiliser (not E85 or E83 with N46 engine)
The 4th generation EWS is an advanced development of the previous electronic immobiliser. This
advanced development uses a new and modern encoding method.
Each vehicle is assigned a 128 bit secret code. This secret code is stored in a BMW database. The secret
code is thus known only to BMW.
The secret code is programmed and locked in the following control units:
-
CAS control unit (not E83)
The electronic immobiliser is integrated into the CAS control unit.
-
EWS control unit (E83 only)
The E83 has an EWS control unit, but no CAS control unit.
-
DME/DDE control unit
When the secret code is locked in the control units, it cannot be cleared or changed. This means that each
control unit is assigned to a specific vehicle. The control units identify themselves with the secret code and
with the same algorithm.
On the 4th generation EWS there is no longer a direct wire (EWS data wire) between the DME/DDE and
the CAS (not E83).
The CAN data wire (PT-CAN and K-CAN) and the K-bus (also known as the CAS bus) are used to transmit
the EWS data signal. The K-bus is used whenever the EWS signal cannot be transmitted on the CAN data
wire.
> E83:Data transmission between the EWS control unit and the DME/DDE via an EWS data wire as
previously.
Air supply: differential air intake control "DISA"
The intake strokes of the pistons generate cyclic pressure waves in the inlet pipe.
These pressure waves travel along the inlet pipe and are reflected by the closed inlet valves.
A precise matching of the inlet pipe length with the valve response time produces the following effect:
Shortly before the inlet valve is closed, a pressure maximum of the reflected air wave reaches the inlet valve.
This has a supercharging effect which pumps a higher proportion of fresh air into the cylinder.
The differentiated air intake system also makes use of the inherent benefits of both short and long inlet pipes.
•
The effect of short inlet pipes or inlet pipes with a large diameter is a high efficiency in the upper engine
speed range (and also low torque in the medium engine speed range).
•
Long inlet pipes or inlet pipes with a small diameter make high torque in the medium engine speed range
possible.
A front intake pipe is installed upstream of each resonating pipe. When the sliding sleeves are closed, the
SBT Engine control for N45, N46 E46, E60, E81, E83, E85, E87, E90, E91, E92, E93
BMW AG - TIS
20.01.2013 20:52
Issue status (12/2007) Valid only until next DVD is issued
Copyright
Page - 10 -
