2001 BMW 525i STARTER MOTOR

Downloaded from www.Manualslib.com manuals search engine
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.
LBuntr.yP~sbhnllcn.can#-AII A,~iltl Rcsrwsd

Downloaded from www.Manualslib.com manuals search engine
.-
-6val and Installation -
< Remove intake manifold mounting hardware (arrows).
NOTE-
M52 TU engine shown. M52 and M54 engines are similar.
Liit up manifold just enough to remove positive cables from
starter motor terminal
50 (arrow).
- Remove intake manifold from cylinder head while carefully
checking for electrical connections, tie wraps, and hoses.
CAUTION-
Stuff clean rags into open intake ports to prevent any parts
from falling into the engine intake.
4 Remove fastener (A) and harness connector (B) from
alternator.

Downloaded from www.Manualslib.com manuals search engine
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.

Downloaded from www.Manualslib.com manuals search engine
Battery, Starter, ~lternatorl
@ TO fuse & relay panel Battery Safety Terminal
A Battery Safety Terminal (BST) controlled by the Multiple
Restraint System (MRS) control unit was introduced for mod-
el year 1998
vehicles. The system will disconnect electrical
power to the engine compartment
in the event of a significant
impact. The MRS system fires an encapsulated pyrotechnic
device
in the positive (+) battery terminal that disconnects
power to the engine compartment, but maintains power to
the exterior lights and interior of the vehicle.
point
002125~1
Table a. Battery, alternator and starter troubleshooting
1-
/Starter motor or solenoid faulty. l~est starter.
Symptom
Engine does not crank
Engine cranks slowly or
not at all, solenoid
clicits
when starter is operated.
I I
Battery will not stay IShort circuit draining battery. l~est for excessive current drain with everything
Probable cause
Fault
in immobilizer system (EWS)
-Clean Battery cables loose, dirty or corroded.
Battery discharged.
Battery to body ground cable in trunk
loose,
dirty or corroded
Poor connection at starter motor terminal
30.
Corrective action
Try another ignition key. If problem persists, contact
your authorized BMW dealer.
or replace cables. See 020
~aintenance.
Charge battery and test. Replace if necessary.
inspect ground cable. Clean, tighten or replace if
necessary.
Checlc connections, test for voltage at starter. Test for
voltage at neutral safety or clutch
interloclc switch.
charged more than a few
days.
I~atter~ faulty. /Test battery and replace if necessary.
Short driving trips and high electrical drain
on
charging system does not allow battery to
recharge.
. I
I Battery cables loose, dirty or corroded. Iclean or replace cables. See 020 Maintenance.
Evaluate driving
style. Where possible, reduce
electrical
consumption when malting short trips.
Drive
belt@) loose, worn or damaged.
IAlternator or voltage regulator faulty. /Test alternator and voltage regulator.
Inspect
or replace ribbed
belt@). See 020
Maintenance.

Downloaded from www.Manualslib.com manuals search engine
I Battery, Starter, Alternator
- Check for battery voltage at terminal 50 of starter motor with
key in start position. If voltage is not present, check wiring be-
tween ignition switch and starter terminal. Check the EWS
system and other inputs that disrupt terminal
56 to the start-
er. See ELE Electrical
Wiring Diagrams. If voltage is
present and no other visible wiring faults can be found, prob-
lem is most likely in starter motor.
Starter, removing and installing
(6-cylinder engine)
The starter is removed from below. Access to starter bolts is
difficult. Be sure to have the proper tools on hand before pro-
ceeding.
NOTE-
Access to the starter wiring is very limited. Forbetteraccess,
it may be necessary to remove the intake manifold.
- Disconnect negative (-) battery cable.
CAUTIOI\C
Prior to disconnecting the battern read the baltery discon-
nection cautions
in OOlGeneral Cautions and Warnings.
Remove complete air filter hous~ng:
Loosen intake duct hose clamp (A) at throttle assembly.
Loosen clamp and remove idle control hose from intake
duct
(B) and disconnect idle speed control valve electrical
harness connector.
Disconnect electrical harness connector
(C) from mass air
flow sensor.
Remove air filter housing mounting screw (D)
Disconnect vent tube
(E).
Loosen air intake duct clamp (F).
Carefully lift air filter housing out of engine bay.
Disconnect throttle cable.
Raise vehicle and support safely.
WARNING-
Make sure the car is stable and well supported at all times.
Use a professional automotive
lift orjack stands designed for
the purpose. A
floorjaclc is not adequate support
- Working underneath car, remove engine splash shield
- Disconnect fuel lines and harness connectors from retaining
brackets, as necessary.

Downloaded from www.Manualslib.com manuals search engine
121-23
Battery, Starter, ~lternatorl
Solenoid switch, removing and installing
- Remove starter as described previously.
- Disconnect field winding strap between starter motor and
solenoid switch.
NOTE-
If the field winding strap is damaged or burned, a new or
rebuilt starter motor is needed.
< Remove solenoid switch mounting screws (arrows), and
separate solenoid from starter.
Unhoolc solenoid plunger from lever in starter drive
- Installation is reverse of removal. Lubricate solenoid piston
with light grease.
CAUTION- When installing field winding strap to starter, position
itso that
it does not contact the starter body.
Tightening torque
Field strap to starter
13 Nm (10 ff-lb)

Downloaded from www.Manualslib.com manuals search engine
INDEX 'tl
WARNING
Your common sense, good
judgemenl, and general alertness are
crucial to sale and successiul service
worlr. Belore attempting any work on
your
BMM be sure lo read 001
General Warnings and Cautions
and the
copyriglll page at the front 01
the manual. Review these warnings
and
caulions each lime you prepare
lo work on your BMW. Please also
read any warnings and cautions that
accompany
tile procedures in the
manual.
312-way valve (running losses)
see Fuel tank
Abbreviations, commonly used 600-14
ABS (antilock brake system)
see
Bral(es
A/C air distribution motors
see stepper motors (below)
blower final stage (resistor pack),
replacing
640-16
blower, removinglinslalling
640-1 5
compressor, replacing
640-24 condenser, replacing 64045
control panellmodule, removing1
installing
640-1 1
evaporakr, removinglinstalling 640-29
evaporator temperature sensor
640-12 expansion valve, removinglinstailing
640-27
IHKA/ IHKR system description 640-5
receiveridrier, replacing 640-26
stepper motors 640-1 3 ventilation microiilter, replacing
020-22. 640-17
see also Heating
Accelerator
iinlcage
see Maintenance
Activated carbon canister
see Fuel tank
ADS (auxiliary throttle valve)
130-57
Air compressor
330-44
Air conditioning
see
AIC
Air distribution (flap) motors
seeNC, stepper motors
Air filter see Maintenance
Air spring
300-6, 330-12
Airbag system (SRS)
2-stage
airbag 721-4
control module, replacing 721-7 driver airbag, removinglinstalling
721-8
iiead protection airbag 721-12 components 721-1 1
indicator
lighl721-4
passenger airbag, removinglinstalling
721-9 side-impact airbags crash sensor,
replacing
721-7
Airflow sensor see 130 under appropriate
fuel
injection system
Air pump
see 130 under appropriate fuel
injection system, secondary air
injection system
Air suspension
see Electronic height control
(EHC)
Alarm
see Anti-theft alarm
Alignment see
Wheei alignment
Aluminum suspension components
300-2
Antenna 650-6
Alternator see Battery, starter, alte rnator
Amplifier
650-4
Anti-theft alarm (DWA)
515-24 emergency disarming 515-31
Antifreeze (engine coolant)
see Maintenance
see also Cooling system
Antilock brake system (ABS) see Brakes
ASC see Brakes
ATF (automatic transmission fluid)
see Automatic transmission
see also Cooling systern
Automatic headlight adjustmenl
(LWR) see Lights
Automatic seat belt tensioner
720-4
Automatic shiftloclc
see
Gearshift
Automatic transmission
applications
200-3, 240-4
ATF 020-10, 200-4
capacity 240-8 checking 240-6
drainingifilling 240-7
heat exchanger 170-5
fluid pan and strainer 240-9 gearshift
see Gearshift
ID tag
200-3 range switch 610-6
removaliinstallation 240-10
steptronic see Gearshift
Auxiliary cooling fan
see
Coollng system, electric Ian
Auxiliary throttle valve (ADS)
130-57
Axle joint
see Drive axle
Back-up light switch
automatic transmission see Automatic transmission. range switch
- .~.~~~
manual transmission 230-8 -
- I

Downloaded from www.Manualslib.com manuals search engine
2 INDEX
Battery, starter, alternator
alternator (generator)
121-10
6-cylinder engine, removingi
installing 121-15
M62 engine 121-16
M62 TU engine (water cooled)
121-18
battery
121-5 charging 121-9
safety terminal 121-3
testing 121-5 charging system, troubleshooting
121-12
starter
121-1 9
6-cylinder engine, removingi instaliinq 121-20 . V-8 engine, rernovinglinsialiing
121-21
solenoid, removinglinstalling
121-23 troubleshooting 121-19
see also Maintenance
Bearing, wheel
see Front suspension
see also Rear suspension
Belts see Maintenance, drive belts
Blade, wiper
see Wipers and Washers
Blower motor see
A/C
BMW emblem
see Exterior trim
BMW special tools 010-18 see also special tools section at
beginning
of each repair group
Body dimensions 400-2
interior features
400-9 salety and security 400-7
Body side molding
see Exterior trim
Bonnet see Engine hood
Boot see Trunk
Brake fluid
020-24, 340-8
Brake fluid pressure sensor
340-30
Brakes
ABS, ASC or DSC system
300-12
component replacement 340-26
ASCIDSC switch
see Switches
bleeding
bralces 340-8
brake booster 340-1 9 bralce Dads. caiioers and rotors ,., 340-1 1
descriotion 300-10
e~ectrdnic brake & stability 300-11
light switch
see Switches
master cylinder
340-16 pariking brake 340-22
troubleshooting 340-5
Bulbs see Lights
Bumper
lront 510-6 height, adjusting 510-12
rear 510-9
Bus system
600-4
Camber
320-33
Camshaft
removingiinslaiiing
M52 engine 116-12
M52 TU
/ M54 engine 116-1 9 M62 engine 11 6-39
wear
116-6
Camshaft position sensors
see ignition system
Camshaft timing chain
adjusting M52 engine
117-22
M52 TU I M54 engine 117-43
M62 engine 117-79 removinglinstalling
M52 engine 117-26
M52TU 1 M54 engine 113-46.116-
28
M62 engine 117-66
Capacities, fluid
020.10
Car rnemorvlicev memorv . . 600-10
see also Centrai
lociking
Carbon canister, activated
see Fuel
tank
Caster
320-33
Catalytic converter and oxygen sensor 020-19
see also Exhaust system: exhaust
manilolds
Cautions
001-3
CD changer
650-4
Center bearing, driveshaft
see Driveshait
Center brake light
sedan
630-13
Center console
513-3
Centrai body electronics (ZKE 111)
600-6
Central locking
car memoryiey memory 515.12 general module iunctions 515-2
remote entry (FZV) 515-8
remote lkey initialization 515-10 single lociddouble ioclk 515-6
switch 515-4
Chain
see Camshaft liming chain
Characteristic map (electrically heated) thermostat
see Electrically heated thermostat
Charging system
see Battery, starter, alternator
Cluster see instruments
Clutch fluid see Maintenance
hydraulics
210-4
mechanical 210-9
switch
see Switches, pedal ciuster
variations
210.10
Codes, fault OED-1
Coil
see Ignition system
Coil spring
see Front suspension
see also Rear
suspe nsion