2000 BMW 740i Bmw

5
BASIC FUNCTION OF BMW VANOS SYSTEMS
All BMW VANOS systems are operated through electric/hydraulic/mechanical control.
Electric Control: The engine control module is responsible for activating a VANOS sole-
noid valve based on DME program mapping. The activation parameters are influenced
by the following input signals:
• Engine speed
• Load (intake air mass)
• Engine temperature
• Camshaft position
• Oil temperature (MS 42.0 only)
Depending on the specific VANOS system, the solenoid valve is one of two types:
• Basic black/white (on/off) solenoid valve. Found on M50 TU and M52 engines.
• Variable position solenoid valve. Found on the M52 TU and M62 TU engines.
Hydraulic Control:The position of the solenoid valve directs the hydraulic flow of engine
oil. The controlled oil flow acts on the mechanical components of VANOS system to
position the camshaft.
Mechanical Control: The mechanical components of all VANOS systems operate under
the same principle. The controlled hydraulic engine oil flow is directed through advance
or retard activation oil ports. Each port exits into a sealed chamber on the opposite sides
of a control piston.
• The control piston on six cylinder engine systems (M50TU, M52 & M52TU) is con-
nected to a separate helical gear cup.
• The control piston on the M62TU VANOS system incorporates the helical gear.
In its default position the oil flow is directed to the rear surface of the piston. This pulls
the helical gear forward and maintains the retarded valve timing position.
When the oil flow is directed to the front surface of the piston, the oil pushesthe helical
gear in the opposite direction which rotates the matched helical gearing connected to the
camshaft.
The angled teeth of the helical gears cause thepushingmovement to be converted into
arotationalmovement. The rotational movement is added to the turning of the
camshaft providing the variable camshaft positioning.

15
DME-ME 7.2 ENGINE MANAGEMENT SYSTEM
The “ME” designation identifies the system as “M” = Motronic, “E” = EML.
• Manufactured by Bosch to BMW specifica-
tions
• 134 pin SKE (standard shell construction) con-
trol module located in E box
• Diagnostic communication protocol-KWP2000
• Uses break-out box set (P/N 90 88 6 121 300)
• Integral EML throttle control system
- monitors an interior installed PWG
- actuates an electric throttle valve (EDK)
• Integral Cruise control functionality
- monitors cruise control requests
- monitors brake pedal and clutch switches
- carries out throttle control directly via EDK
• Carries out DSC III torque reduction requests.
• VANOS control
• Integrated altitude sensor
• Integrated temp sensor for monitoring E box
temperatures
• Control of E-box fan
• One touch engine start control
• Oxygen Sensor heating
• Engine overrev & Max speed limitation
• Active Hall sensor for camshaft position monitoring
• Single speed secondary air injection system
• Electrically heated coolant system thermostat
• Longlife spark plugs
• IHKA Auxiliary Fan control
•DM-TL (Diagnostic Module - Tank Leak Diagnosis System)
ME 7.2 LOCATION IN E-BOX
1
(9 pins)2
(24 pins)3
(52 pins)4
(40 pins)5
(9 pins)

31
DM-TL (DIAGNOSIS MODULE - TANK LEAKAGE)
INTRODUCTION
A new Fuel System Leak Diagnosis Pump is equipped on the X5. The pump will eventu-
ally replace the current vacuum LDP on all vehicles.
The pump is manufactured by Bosch to BMW specifications.
• Bosch ECMs identify the electrical function of the pump as DM-TL.