of quality OBD scan tools.
In addition to the BMW
professional line of scan tools,
there are many inexpensive
`generic' OBD II scan tool software
programs and handheld units
available. Although these tools
have limited capabilities as
compared to the dedicated tools,
they are powerful diagnostic tools.
These tools read live data
streams, freeze frame information
for DTCs (diagnostic trouble
codes) and impending DTCs, as
well as a host of other valuable
diagnostic data.
For the DIY owner, simple
aftermarket DTC readers are also
available. These inexpensive
BMW-only tools are capable of
checking for DTCs as well as
turning off the illuminated MIL, and
resetting the service indicator
lights.
See
020 Maintenance
for
specialty tool manufacturer contact
information.
Principle of operation
The DME fuel injection system is
completely electronic in operation.
Intake air, engine coolant temperature,
crank and camshaft positions, engine
speed and many other engine
operating parameters are measured
electronically and the information is
supplied to the engine control module
(ECM).
Based on input information, the ECM
controls the ignition coils, fuel injectors,
Fuel Injection
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