2001 BMW 540i spark plugs

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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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.-
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.

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130-67
Fuel Injection /
ME 7.2 system overview
The Bosch ME 7.2 system is used on 1999 - 2002 540i mod-
els.
1 4 The ME 7.2 enaine control module (ECM). located on the
l and a combined total of 134 pins.
--__-- 1 I. 9 pin connector
12 3 4 5 2 24 pin connector
0lliC;nii, 3. 52 pin connector
4. 40 pin connector
5. 9 pin connector
The ME 7.2 system has the following functions or capabilities:
Electronic throttle control (EDK) integrates idle and cruise
control functions. ECM carries out all throttle and idle con-
trol functions directly via EDK system.
Leak diagnosis pump
(LDP) control and feedback monitor-
ing for evaporative system leak testing.
Batterylalternator charge logic (idle speed varies with bat-
tery state of charge).
CAN-Bus communications with instrument cluster.
EWS
111 (3.3) "rolling code" ISN interface.
Ignition
knock sensors.
DSC (dynamic stability control) torque reduction.
Monitoring and control of VANOS
(camshaft timing) with
active Hail sensor for camshaft position monitoring.
Integrated altitude sensor.
One touch engine start control
Single speed secondary air injection system.
Long life spark plugs.
IHKA auxiliary (electric) cooling fan control.
All emissions-related ME 7.2 electrical components are mon-
itored for faults. if driveability complaints are encountered or
the malfunction indicator
light (MIL) is illuminated, interrogate
fault memory using a compatible scan tool.
4 Use a break-out box for ME 7.2 system testing and diagnosis
at the control module
(break out box set: BMW special tool
90
88 6 121 300).
Electrically heated (characteristic
map) cooling system
DME Harness Connector thermostat.

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INDEX 7
WARNING
Your common sense, good
judgement, and general alertness are
crucial to safe and successful service
work. Before
attempting any work on
your BMW, be sure to read 001
General Warnings and Cautions
and the copyright page at the front of
the manual. Review these warnings
and cautions each time you prepare
to
work on your BMW. Please also
read any warnings and
caulions that
accompany
/he procedures in the
manual.
Jack stands
010-16
Jump starting 010-19
Keys
515-1 1
Knock sensor
see Ignition system
Leak detection,
fuel tanlr
see Fuel tank, leak detection unit
Leather upholstery
see Maintenance, leather
upholstery and trim
LDP
(leak detection pump)
see Fuel
tanir, leal( detection unit
Level sender
see Fuel tank
see also Fuel pump
License
plate iight
630-1 1
Lifters see Cylinder head and vaivetrain
Lifting the car
010-5 Lights
bulb applications
630-2
control module (LCM) 630-3
foglights 630-8 headiighls 630-4
automatic headlight adjustment
(LWR)
630-7
vertical aim system 630-8 interior lights 630-12
bulb applications 630-13
side turn signal 630-9
taillight 630.10 trunk light bulb 630-14
turn signals, taillights 630-12
LOClCS see Central loci(ing
see also Door loclrs
Lubrication system
oil
level warning switch, replacing
119-20
oil pan, removinglinstalling
6-cylinder 119-10
V-E lower 119-13 V-8 upper 119-15
oil pressure
checiring 11
9-4
warning system, testing 119-5 warning switch, replacing 119-20
oil pressure
reliel valve
6-cylinder 119-26
V-8 11 9-27
oil pump, removinglinstalling
6-cylinder
119-22
V-8 1 19-4
troubieshooting 119-3
Luggage compartment
seeTrunk
MAF (mass air flow) sensor
see 130 under appropriate fuel
injection system Maintenance
accelerator linkage
020-14 air filter 020-14
automatic transmission 020-29
battery 020-22
body lubrication 020-31 body and interior 020-31
braire fluid 020-24
brake padlrotor wear 020-24
brake system 020-25 clutch fluid 020-26
cooling system 020-15
CV ioint boots 020-27
differential oil level 020-26
drive bells 020-16 engine comparlmenl 020-14
engine cooling system 020-16
engine oil 020-1 1 exhaust system 020-27
exterior washing 020-31
fluid and lubricant specifications 020-9
fuel lilter 020-27 fuel lanir and fuel lines 20-28
idle speed 020-19
inspection 020-5
interior care 020-31
lealher upholslery and trim 020-31
maintenance tables 020-6
manual transmission oil 020-30
microiilter 020-22 oxygen sensors 130-72, 180-8
parlcing brake 020-25
power steering fluid level 020-20
seat belts
020-32 service indicator 020-3
spark plugs 020-20
special cleaning 020-32 suspension, front 020-29
suspension, rear 020-29
tires 020-29
washing
020-32
waxing 020-32 windshield wiper blade 020-33
wheels, aligning 020-30
Malfunction indicator iight (MIL)
OED-2
Manifold, exhaust
see Exhaust system
Manifold,
intake
see Intake maniiold

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INDEX 9
WARNING
Your common sense, good judgemenl, and general alerlness are
crucial lo seie end successful service
ivork. Beiore attempting any work on
your
BMW be sure to read 001
General Warnings and Cautions and llle copyright page at lhe iron1 of
the manual. Review Niese warnings
and caulions each lime you prepare
lo work on your BMW Please also
read any warnings and caulions lllal accompany the procedures in the
manual.
Rear suspension
ball joints
330-19
bushings 330-13
control arms
seesuspension arms, below
description
300-5
electronic height control (EHC)
330-44
ride height 300-14 ride height sensor 330-46
shoclr absorbers end springs 330-9
stabilizer bar 330-42
struts and springs 330-5 subframe 330.13
suspension arms 330-13
variations 330-4 wheel bearing, replacing 330-32
see also Maintenance
see also Drive axles
see also Final drive
Rear window (Sport Wagon)
see
Tailgate
Rear window defroster 610-17
Receiverldrter
see NC
Relay positions
see Electrical component tocations
table 610-3
Remote entry (FZV)
see Central locking
Reversing light switch
see
Baclc-up light switch
Ride height
300-14
Ride height sensor
see Rear suspension
Ring antenna
see EWS (electronic immobilizalion)
Rotor
see Brakes
Roundel see Exterior trim
Running tosses
(312-way) valve
see Fuel
tenlr
SCA (soft close)
seeTailgate, soft close
see also Trunk lid. soft close
Scan tools
OED-3
Seals gaskets and 010-9
see also Crankshaft seals
Seat front,
removing/instelling 520-10
memory system 520-4 rear 520-13
see also Seat belt
Seat beit front 720-4
rear 720-8
troubleshooting 7202
see also Maintenance
Secondary air injection
see 130 under appropriate
iuel
injection system
Selector shaft seat
see Manual transmission, oil
Seals
Self-adjusting ctulch (SAC)
see Clutch, variations
Service indicator see Maintenance
Shift interlock see Gearshift
Shift lever
see
Gearshift
Shift linkage see Gearshift
Shiftlock see Gearshilt
Shack absorber see Rear suspension
/ Side turn signal assembly
see Lights
Sill trim panel
411-10
Slave cylinder
see Clutch, lhydraulic
Steep mode
600-1 1
Soft close
(SCA) see Tailgate
see also
Trunk lid
Solenoid 121-23
Sound system
650-2
Spare parts kit
010-21
Spark plugs
see Maintenance
Speakers
650-4
Specifications, fluid
020-4
Sport wagon
400-4
Springs
see Front suspension
see also Rear suspension
SRS (supplemental restraint system)
see
Airbag system (SRS)
Stabilizer bar see Front suspension
see also Rear suspension
Starter see Battery, starter, alternator