2000 BMW 528i IGNITION COILS

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Camshaft Timing Chain
VANOS control unit, removing
(M52 TU and M54 engines)
This procedure includes removal of the Double VANOS con-
trol unit.
NOTE-
If the Double VANOS control unit is being replaced, camshaft
timing must be checked. This procedure requires multiple
special tools. Be sure to read the procedures through before
beginning the repair.
- Working inside luggage compartment, disconnect negative
(-) battery cable.
Prior to disconnecting the
batteg read the battery discon-
nection cautions given in
001 General Cautions and
Remove engine cooling fan assembly. See 170 Radiator
and Cooling System.
Remove engine trim covers.
Pry out plastic trim caps (arrows).
Remove cover fasteners, oil filler cap, and covers.
Remove ignition coils:
Disconnect ignition coil electrical harness connectors.
Remove coil mounting fasteners and coils.
NOTE-
Make note of ignition coil ground strap locations.
Remove spark plugs,

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Camshaft Timing chain1
- Disconnect negative cable (-) from battery.
CAUTION-
Prior to disconnecting the battery, read the battery discon-
nection cautions given
in 001 General Cautions and
Warnings.
4 Removing top and side engine covers:
Press down on locking pins (arrows) to release locks. Lifl
intake manifold cover straight up to remove.
Pry out caps from side covers.
Remove fasteners
and covers.
NOTE-
Some early models use
pry out trim caps and fasteners to
hold the top cover in place.
Disconnect electrical harness connectors at ignition coils
(A).
Remove left and right side ignition coil mounting fasteners
and coils.
NOTE-
Make note of location of ground strap (arrow).
Remove spark plugs.
- Remove posltlve (+) terminal cable from left cylrnder head
cover.
- Unbolt left and right side cable ducts from fuel rail
Remove air filter housing and mass air flow sensor:
Disconnect mass air flow sensor and intake air tempera-
ture sensor electrical harnesses
(A and B).
Remove air filter housing mounting fastener (arrow)
Loosen intake hose clamp
(C).
Remove air filter housing with mass air sensor and intake
duct from throttle body assembly.

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1 17-68
Camshaft Timing Chain
4 Remove left and right side ignition coils and spark plugs:
- Remove positive (+) terminal cable from left cylinder head
cover.
- Unbolt lefl and right side cable ducts from fuel rail,
4 Disconnect fuel injector electrical connectors:
Pry corner of wire lock clip to release connector from injec-
tor
(arrow).
Repeat for all injectors.
Lift off wiring ducts.
4 Remove Fasteners (arrow) from lefl and right cylinder head
cover fasteners and remove covers.

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Camshaft Timing Chain LL. .- - - - I
4 Remove left and right side ignition coils and spark plugs:
- Disconnect electrical harness connectors at ignition coils
(A).
Remove left and right side ignition coil mounting fasteners
and coils.
NOTE-
Make note of location of ground strap (arrow).
Remove sparlc plugs.
- Remove positive (+) terminal cable from left cylinder head
cover.
- Unbolt cable ducts from fuel rail at left and right sides.
Disconnect fuel injector electrical connectors from injectors:
Pry corner of wire
loclc clip (arrow) to release connector.
Repeat for remaining injectors.
* Lift off wiring ducts.

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120-3
Ignition System
Warnings and cautions
The ignition system produces dangerous high voltage. In ad-
dition the sensitive electronic components can be damaged
if
proper precautions are not adhered to.
WARNING-
* Do not touch or disconnect any cables from the coils while
the engine is running or being
cranked by the starter.
The ignition system produces high voltages that can be
fatal. Avoid contact with exposed terminals. Use ex-
treme caution when working on a car with the ignition
switched on or the engine running.
- Connect and disconnect tlie DME system wiring and
test equipment leads only when the ignition is
OFF:
Before operating the starter without starting the engine
(for example when
making a compression test) always
disable the ignition.
CA
U TIOW-
Do not attempt to disable the ignition by removing the coils
from the spark plugs.
Connect or disconnect ignition system wires, multiple
wire connectors, and ignition test equipment leads only
while the ignition is
off Switch multimeter functions or
measurement ranges only with the test probes discon-
nected.
* Do not disconnect the battery while the engine is run-
ning.
A high impedance digital multimeter should be used for
all voltage and resistance tests. An LED test light
should be used in place of an incandescent-type test
lamp.
In general, make test connections only as specified by
BMW as described in this manual, or as described by
the instrument manufacturer.
Engine management
BMW €39 engines use an advanced engine management
system known as Digital Motor Electronics (DME). DME in-
corporates on-board diagnostics, fuel injection, ignition and
other engine control functions. DME variants are listed in
Table a. Engine management systems.
Second generation On-Board Diagnostics
(OED II) is incor-
porated into the engine management systems used on the
cars covered by this manual. Use a BMW-specific electronic
scan tool, or a "Generic"
OED II scan tool to access Diagnos-
tic Trouble Codes (DTCs). DTCs can help pinpoint ignition
ine management problems.

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I lgnition System
Additional information about DTCs and engine management
system electronic system diagnosis is provided in
OBD On-
Board Diagnostics.
Table a. Engine management systems
Year
l~ngine I Engine type IDME svstem I - I - . . I
Ignition system
1997-1 998
1997
1998
1999-2002
4 All engines use a distributorless ignition system with individ-
ual ignition coils for each cylinder. There is no distributor cap
or ignition rotor.
4 Each coil is controlled and monitored by the Engine Control
Module (ECM) on a cylinder-by-cylinder basis.
1999-2000
1~52 TU 16-cylinder l~iemens MS
42.0
M62
M62
M62TU
Siemens MS 41 .I M52 6-cylinder
V-8
V-8 V-8 Bosch
M 5.2
Bosch M 5.2.1
Bosch ME 7.2

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Lnition switch
4 The positive (+) power supply to the ignition coils comes to
the ignition switch via an unloader relay. When the ignition
switch is turned on, the relay closes, to provide voltage to the
ignition coils. The coils are then actuated at the negative side
by the engine control module.
NOTE-
Schematic diagrams shown are for illustrative purposes only.
See ELE Electrical Wiring Diagrams for engine manage-
ment specific wiring information.
WARNING- Do not touch or disconnect any cables from the coils while
the engine is running or being cranked by the starter:
The ignition system produces high voltages that can be
fatal. Avoid contact with exposed terminals. Use ex-
treme caution when
working on a car with the ignition
switched on or the engine running.
* Connect and disconnect the DME system wiring and
test equipment leads only when the ignition is
OFF
Before operating the starter without starting the engine
(for example when
making a compression test), always
disable the ignition.
4 Knock sensors (arrows) monitor the combustion chamber for
engine-damaging knock. Six-cylinder models (shown) use
two sensors with each sensor monitoring three cylinders.
V-
8 models use four sensors, each monitoring two cylinders. If
engine
knock is detected, the ignition point is retarded by the
ECM.
I Ignition advance Ignition timing is electronically mapped and not adjustable.
The ECM uses engine load, engine speed, coolant tempera-
ture, knock detection, and intake air temperature as the basic
inputs for timing control.
A three dimensional map similar to
the one shown is digitally stored in the ECM.
- The initial ignition point is determined by the crankshaft
speed sensor during cranking. Once the engine is running.
timing is continually adjusted based on operating conditions.

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.-
ignition System
Disabling ignition system
The ignition system operates in a lethal voltage range and
should be disabled any time engine service or repair work is
being done that requires the ignition to be switched on.
The engine management system can be disabled by remov-
ing the DME main relay. The relay is located in the electronics
box (E-box) in the left rear of the engine
compartment, be.
neath the interior microfilter housing.
CAUTION- Relay locations may
vary. Use care when identifying relays.
See
610 Electrical Component Locations.
Checking for spark
CAUTION-
If
a spark test is done incorrecth damage to the Engine Con-
trol Module
(ECM) or the ignition coils may result.
NOTE-
Spark plug replacement is covered in 020 Maintenance.
Check~ng for spark is d~fflcult on englnes wlth d~str~butorless
ignition systems.
Try removing the spark plugs and inspecting for differences between them.
A poor-firing plug may be wet with fuel and/or ~. - ~
black and sooty, but not always. If a coil is not operating, the
engine management system will electrically disable the fuel
injector to that cylinder. The key is to look for differences be-
tween cylinders.
Ignition coil assembly, testing and
replacing
C4 UTION-
Use a digital multimeter for the following tests. I
- Remove plastic engine cover from top of valve cover by pry-
ing off bolt covers and removing cover mounting bolts.
- Raise car slowly while constantly checking position of jack
and car.
- Disconnect harness connector from coil. Connect multimeter
between terminal 15
(+) in connector and ground.
4 Terminal identification are typically molded into connector. In
photo, terminals are from left to right: 1,
4a, 15.