2006 BMW X5 Ecm

45
M54engMS43/ST036/6/20000
IDLE SPEED CONTROL
The ECM determines idle speed by controlling an idle speed actuator (dual winding rotary
actuator) ZWD 5.
The basic functions of the idle speed control are:
• Control the initial air quantity
(at air temperatures <0 C,
the EDK is simultaneously
opened)
• Variable preset idle based on
load and inputs
• Monitor RPM feedback for
each preset position
• Lower RPM range intake air
flow (even while driving)
• Vacuum limitation
• Smooth out the transition from acceleration to deceleration
Under certain engine operating parameters, the EDK throttle control and the idle speed
actuator (ZWD) are operated simultaneously.This includes All idling conditions and the tran-
sition from off idle to load.
As the request for load increases, the idle valve will remain open and the EDK will supply
any additional air volume required to meet the demand.
Emergency Operation of Idle Speed Actuator:
If a fault is detected with the idle speed actuator, the ECM will initiate failsafe measures
depending on the effect of the fault (increased air flow or decreased air flow).
If there is a fault in the idle speed actuator/circuit, the EDK will compensate to maintain idle
speed. The EML lamp will be illuminated to inform the driver of a fault.
If the fault causes increased air flow (actuator failed open), VANOS and Knock Control are
deactivated which noticeably reduces engine performance.
MDK
HFMHFM
MAGNETIC
VALVE
VACUUM
UNIT
MS42.0MS42.0
RAM TUBE
MAIN MAINIFOLD
RESONANCE TUBE
IDLE AIR CONTROL VALVE
(ZWD)
RESONANCE MANIFOLD
CRANKCASE VENTILATIONTURBULENCE MANIFOLD
TURBULENCE BORE 0:5.5mm
MS 43.0
EDK

46
M54engMS43/ST036/6/2000
CRUISE CONTROL
Cruise control is integrated into the ECM because of the EDK operation.
Cruise control functions are activated directly by the multifunction steering wheel to the
ECM. The individual buttons are digitally encoded in the MFL switch and is input to the ECM
over a serial data wire.
The ECM controls vehicle speed by activation of the Electronic Throttle Valve (EDK)
The clutch switch disengages cruise control to prevent over-rev during gear changes.
The brake light switch and the brake light test switch are input to the ECM to disengage
cruise control as well as fault recognition during engine operation of the EDK.
Road speed is input to the ECM for cruise control as well as DSC regulation. The vehicle
speed signal for normal engine operation is supplied from the DSC module (right rear wheel
speed sensor). The road speed signal for cruise control is supplied from the DSC module.
This is an average taken from both front wheel speed sensors, supplied via the CAN bus.
DSCMS 43.0
EDK

47
M54engMS43/ST036/6/20000
PURGE VALVE
The purge valve (TEV) is activated at 10 Hz by the ECM to cycle open, and is sprung
closed. The valve is identical to the purge valve used on the Siemens MS 42 system.
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48
M54engMS43/ST036/6/2000
REVIEW QUESTIONS
1. List the major changes to the Siemens MS 43.3 system from MS 42:
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2. What type of signal does the Hall Sensor - PWG provide to ECM for throttle request?
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3. What PWG signal is used if PWG has a plausibility error?
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4. What is the purpose of the KL 87 main relay monitor in the ECM?
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5. Why is the ignition left ON after KL 15 is switched OFF?
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6. Describe the operation of the DM-TL system on MS 43.0.
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7. Describe the operation of the turbulence - resonance manifold.
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