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123
DM-TL (DIAGNOSIS MODULE - TANK LEAKAGE)
FUNCTIONAL OVERVIEW:
The DM-TL is located in the drivers side rear wheel well in the X5 and next to the charcoal
canister on the E46 - M54.
1. In it’s inactive state, filtered fresh air enters the evaporative system through the sprung
open valve of the DM-TL.
2. When the DME activates the DM-TL for leak testing, it first activates only the pump
motor. This pumps air through a restrictor orifice (1.0 or 0.5 mm) which causes the elec-
tric motor to draw a specific amperage value. This value is equivalent to the size of the
restrictor.
3. The solenoid valve is then energized which seals the evap system and directs the pump
output to pressurize the evap system.
The evap system is detected as having a large leak if the amperage value is not realized, a
small leak if the same reference amperage is realized or no leak if the amperage value is
higher than the reference amperage.
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M54engMS43/ST036/6/2000
CAMSHAFT SENSOR
-INTAKE AND EXHAUST CAMSHAFTS
The "static" Hall sensors are used so that the camshaft positions are recognized once igni-
tion is “on” - even before the engine is started.
The function of the intake cam sensor:
• Cylinder bank detection for preliminary injection
• Synchronization
• Engine speed sensor (if crankshaft speed sensor fails)
• Position control of the intake cam (VANOS)
The exhaust cam sensor is used for position control of the exhaust cam (VANOS)
If these sensors fail there are no substitute values, the system will operate in the failsafe
mode with no VANOS adjustment. The engine will still operate, but torque reduction will be
noticeable.
NOTE: Use caution on repairs as not to bend the impulse wheels
KL 15 KL 15
MS42.0
SOLENOID
OIL TEMP.
SENSOR TWO POSITION PISTON HOUSING
WITH INTERNAL/EXTERNAL
HELICAL GEAR CUP TWO POSITION PISTON
HOUSING WITH
INTERNAL/EXTERNAL
HELICAL GEAR CUP
ENGINE
OIL SUPPLY VENT VENT
SOLENOID
SENSOR SENSOR
MS42
ECM
EXHAUST
INTAKE
MS42.0
ECM
MS 43.0
MS 43.0
MS 43.0
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M54engMS43/ST036/6/20000
CRANKSHAFT SENSOR
The crankshaft sensor is a dynamic Hall-effect sensor (mounted through the engine block),
the signal is sent the moment the crankshaft begins to rotate.
The pulse wheel is mounted directly to the crankshaft as seen on previous models.
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
MS 43.0
SMOOTH RUNNING ENGINE
NOTE SQUARE WAVEENGINE MISFIRE DETECTED
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M54engMS43/ST036/6/2000
MS 43 CARRY OVER FUNCTIONS
OUTPUT FUNCTIONS -VANOS CONTROL
With the double VANOS system, the valve timing is changed on both the intake and the
exhaust camshafts.
Double VANOS provides the following benefits:
• Torque increase in the low to mid (1500 - 2000 RPM) range without power loss in the
upper RPM range.
• Less incomplete combustion when idling due to less camshaft overlap (also improves
idle speed characteristics).
• Internal exhaust gas recirculation (EGR) in the part load range (reduces NOx and post-
combustion of residual gasses in the exhaust)
• Rapid catalyst warm up and lower “raw” emissions after cold start.
• Reduction in fuel consumption
Double VANOS consists of the following parts:
• Intake and exhaust camshafts with helical gear insert
• Sprockets with adjustable gears
• VANOS actuators for each camshaft
• 2 three-way solenoid switching valves
• 2 impulse wheels for detecting camshaft position
• 2 camshaft position sensors (Hall effect)
The “initial” timing is set by gear positioning (refer to the Repair Instructions for details) and
the chain tensioner. As with the previous VANOS, the hydraulically controlled actuators
move the helical geared cups to regulate camshaft timing. The angled teeth of the helical
gears cause the pushing
movement of the helical cup to be converted into a rotational
movement. This rotational movement is added to the turning of the camshafts and cause
the camshafts to “advance” or “retard”. The adjustment rate is dependent oil temperature,
oil pressure, and engine RPM.
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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