oil BMW X5 2002 E53 M54 Engine Workshop Manual

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M54engMS43/ST036/6/2000
MS 43 NEW FUNCTIONS
EMISSION OPTIMIZED - IGNITION KEY OFF
“Emission Optimized Ignition Key Off” is a programmed feature of the MS 43 control mod-
ule.
After the ECM detects KL 15 being switched OFF, the ignition stays active for two more
individual coil firings. This means that just two cylinders are fired - not two revolutions.
This feature allows residual fuel injected into the cylinders, as the ignition key is switched
off, to be burned as the engine runs down.
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ART-E46ICEMIOPT

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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/ST036/6/2000
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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M54engMS43/ST036/6/20000
NOTE: With extremely hot oil temperatures Vanos is deactivated (Power loss). If the oil is
too thick (wrong viscosity) a fault could be set.
When the engine is started, the camshafts are in the “failsafe” position (deactivated). The
intake camshaft is in the RETARDED position - held by oil pressure from the sprung open
solenoid. The exhaust camshaft is in the ADVANCED position - held by a preload spring in
the actuator and oil pressure from the sprung open solenoid.
After 50 RPM (2-5 seconds) from engine start, the ECM is monitoring the exact camshaft
position.
The ECM positions the camshafts based on engine RPM and the throttle position signal.
From that point the camshaft timing will be varied based on intake air and coolant temper-
atures.
The double VANOS system is “fully variable”. When the ECM detects the camshafts are in
the optimum positions, the solenoids are modulated (approximately 100-220 Hz) maintain-
ing oil pressure on both sides of the actuators to hold the camshaft timing.
CAUTION:
The VANOS MUST
be removed and installed exactly as described in the Repair
Instructions!
NOTE: If the VANOS camshaft system goes to the failsafe mode (deactivated) there will be
a noticeable loss of power. This will be like driving with retarded ignition or starting from a
stop in third gear.
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
ECMEXHAUST
INTAKE
MS42.0
ECM
MS 43.0
MS 43.0
MS 43.0

EXHAUST:Advanced
piston moved in
INTAKE:Retard piston
moved out
EXHAUST:Advanced
piston moved out
INTAKE:Retard piston
moved in
DEACTIVATED
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
ECMEXHAUST
INTAKE
MS42.0
ECM
ACTIVATED
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
ECMEXHAUST
INTAKE
MS42.0
ECM
MS 43.0
MS 43.0
MS 43.0

 
MS 43.0
MS 43.0
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M54 engMS43/STO36/6/2000

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M54engMS43/ST036/6/2000
RZV IGNITION SYSTEM
The Siemens MS43.0 system uses a multiple spark ignition function. The purpose of mul-
tiple ignition is:
• Provide clean burning during engine start up and while idling (reducing emissions).
• This function helps to keep the spark plugs clean for longer service life (new BMW
longlife plugs).
Multiple ignition is active up to an engine speed of approximately 1350 RPM (varied with
engine temperature) and up to 20 degrees after TDC.
Multiple ignition is dependent on battery voltage. When the voltage is low, the primary cur-
rent is also lower and a longer period of time is required to build up the magnetic field in the
coil(s).
• Low battery voltage = less multiple ignitions
• High battery voltage = more multiple ignitions
The 240 ohm shunt resistor is still used on the MS43.0 system for detecting secondary igni-
tion faults and diagnostic purposes.
MS 43.0