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Spare parts kit
Carrying a basic set of spare parts can prevent a rninorbreak-
down from turning into a major repair annoyance. The list be-
low is a good place to start.
Spare parts kit
- basic
Polyribbed drive
belt(s)
BMW engine oil: one or two quarts
BMW engine coolant:
1 gallon of premixed 50150 BMW
anti-freeze and water
Fuse assortment:
7.5A. IOA, 1 5A, 20A, 30A. 50A
Radiator hoses: upper and lower
Spare parts
kit - additional contents
Exterior lighting bulbs: headlight, bralte light, turn signal,
and taillight
* Wiper blades or blade inserts
Brake fluid: new, unopened bottle, DOT
4 specification
Main relay for DME system
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Two common causes of driveability problems are incorrect
system voltage and bad grounds.
System voltage
Digital motor electronics (DME) requires that the system (bat-
tery) voltage be maintained within a narrow range of DC volt-
age.
DC voltage levels beyond or below the operating range,
or any
AIC voltage in the electrical system can cause havoc.
When troubleshooting an illuminated MIL, make sure the bat-
tery is fully charged and capable of delivering all its power to
the electrical system. An undercharged battery can amplify
AIC alternator output ripple.
To
make a quick check of the battery charge, measure the
voltage across the battery terminals with all cables attached
and the ignition off.
Afully charged battery will measure 12.6
volts or slightly more, compared to 12.1 5 volts for a battery
with a 25% charge.
The DME system operates at low voltage and current levels,
making it sensitive to small increases in resistance. The elec-
trical system is routinely subjected to corrosion, vibration and
wear, so faults or corrosion in the wiring harness and connec-
tors are not uncommon. Check the battery terminals
forcorro-
sion or loose cable connections. See 121 Battery, Starter,
Alternator for additional information.
If a battery cable connection has no
v~sible faults but is still
suspect, measure the voltage drop across the connection. A
large drop indicates excessive resistance, meaning that the
connection is corroded, dirty, or damaged. Clean or repairthe
connection and retest.
NOTE-
For instructions on conducting a voltage drop test and other
general electrical troubleshooting information, see
600 Elec-
trical System-General.
Visually inspect all wiring, connectors, switches and fuses in
the system. Loose or damaged connectors can cause inter-
mittent problems, especially the small terminals in the ECM
connectors. Disconnect the wiring harness connectors to
check for corrosion, and use electrical cleaning spray to re-
move contaminants.
Main grounds
Good grounds are critical to proper DME operation. If a
ground connection has no visible faults but is still suspect.
measure the voltage drop across the connection. A large volt-
age drop means high resistance. Clean or repair the connec-
tion and retest.
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100-6
( Engine-General
The main grounds for the fuel and ignition circuits of the DME
system are illustrated below; see 610 Electrical Component
Locations for additional ground and component locations.
4 Ground for engine management system in right rear of en-
gine compartment on E-box bulkhead (arrow).
6-cylinder models: Grounds
for ignition coils (arrows)
4 V-8 models: Grounds for ignition coils, at cylinders 3
(arrow) and 7.
4 Fuel pump ground (arrow) below right tail light in luggage
compartment.
NOTE-
Ground location for sedan shown, wagon models may
differ.
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110-3
Engine Removal and lnstallationl
Q Fuel line plugs
(Tool No.
BMW 13 5 281 / 13 5 282)
4 Fuel line removal tool
(Tool No.
BMW 16 1 050)
CAUTION-
Disconnecting the battery may erase fault code@) storedin
memoiy Check for fault codes prior to disconnecting the
battery cables.
If the MIL (Malfunction Indicator Light, also may be
called "Check Engine" or "Service Engine Soon" light)
is illuminated, see
OBD On-Board Diagnostics for
DME fault code information.
It orhersysrem faults have been detected, as indicated I
by an ~llum~nated ABS, SRS orASC/DSC ~arning light,
see the appropriate repair group in this manual or an
authorized BMW dealer for more information on fault
codes.
NOTE- Engine removal procedures are similar for all 6-cylinder
models. When differences
exist, they are noted at the be-
ginning of each step. Engine are referred to by engine
code. See
100 Engine-General for engine code and appli-
cation information.
@ Be sure to cover all painted surfaces before beginning the
removal procedure. As an aid to installation, label all com-
ponents, wires and hoses before removing them. Do not
reuse
gaskets, O-rings or seals during reassembly.
The
intake manifold must be removed on &cylinder mod-
els before the engine can be removed.
WARNING-
Due to risk of personal injury, be sure the engine is cold be-
fore beginning the removal procedure.
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11 3-6
Cylinder Head Removal and Installation
- Disable ignition system by removing DME main relay. See
610 Component Locations for relay location.
WARNING-
. The ignition system produces high voltages that can be fa-
tal. Avoid contact with exposed terminals and use
exfreme
caution when working on a car with the ignition switched on
or the engine running.
Do not touch or disconnect ignition
components while
the engine is running or being cranked by the starter.
Failure to remove the DME main relay or attempting to
disa-
bie the fuel andignition systems by other methods may result
in damaoe to the enoine control module
(ECM).
- - Remove plastic cylinder head cover(s)
,,I . ,. .*,.,,&- - Remove coil grounding straps.
I CAUTION-
I nition system components. I
- Remove coils.
- Remove spark plugs from all cylinders.
NOTE-
Check the spark plugs for oil deposits that may indicate poor
cylinder sealing, then set them aside in order. Used spark
plugs should be reinstalled in the same cylinder from which
they were removed.
4 Install compression gauge in first cylinder spark plug hole,
tight enough to form a good seal.
- With parking brake set, transmission in PARK or NEUTRAL,
and accelerator pedal pressed to floor, crank engine with
starter. Record highest value indicated by gauge.
NOTE-
* The compression gauge reading should increase with
each compression stroke and reach near its maximum
reading in about
4-6 strokes.
All cylinders should reach maximum compression in the
same number of
strolces. If a cylinder needs significantly
more strokes to reach
maximum compression, there is a
problem.
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Camshaft Timing Chain
1 VANOS I 4 When engine is started, camshafts are in deactivated
camshaft
retarded Engine I i oil supply
position:
. lntalte camshaft is held in RETARDED position by oil
pressure.
Exhaust camshaft is held in ADVANCED position by
preload spring and oil pressure.
VANOS
Piston out
ECM Piston in Within 2
- 5
seconds (50 engine revolutions), the ECM begins
monitoring and controlling camshaft positions.
The Double VANOS system allows full variability of camshaft
timing up to the limits of the system. When the ECM detects
that the camshafts are in optimum position, the solenoids are
modulated at approximately 100
- 220 Hz to maintain oil pres-
sure on both sides of the actuator pistons to maintain timing.
In models with DME
MS 43.0 (model year2001 and newer),
the engine control module (ECM) detects camshaft position
before the engine starts, thereby adjusting camshaft timing
immediately upon start-up.
NOTE-
. VANOS system troubleshooting and diagnostics is best
accomplished using a scan tool.
. Diagnostic Trouble Codes (DTCs) pertaining to the
VANOS system are listed
in the following table. See also
OED On-Board Diagnostics.
Elevated oil temperatures can cause VANOS to deactivate.
Oil that is too thick (high viscosity) may cause
a DTC to be
set
in the ECM. If VANOS is deactivated (limp-home
mode), there will be a noticeable loss of power.
VANOS fault codes
BMW code P-code Fault description
19
PI529 VANOS solenoid valve activation,
exhaust
21
PI525 VANOS solenoid valve activation,
intake
103
PI519 VANOS faulty reference value
intake
104
PI520 VANOS faulty reference value
exhaust
105
PI522 VANOS stuck (Bank I) intake
106
PI523 VANOS stuck (Bank 2) exhaust
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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