2000 BMW 540i Starter

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120-1 2
ignition System
Crankshaftspeedsensor
Crankshaft speed sensor, replacing (M52, M52 TU and
M54 engines)
4 Crankshaft speed sensor for 6-cylinder engine is mounted in
the left rear side of the cylinder block below the starter (ar-
row). The sensor reads a toothed pulse wheel mounted to
the end of the crankshaft.
- if the Engine Control Module (ECM) does not receive a signal
from the crankshaft speed sensor during cranking, the en-
gine will not start.
- If the OBD II svstem misfire detection ~rotocol detects a cat- - - ~~
alysr oarnagin; faLlt oJe to a ma I-nclion in crandshafi speeo
sensor components. Ine Check Engine
lignr (Malfuncrion In-
dicator Light or MIL) will be illuminated.
NOTE-
If the crankshaft speed sensor pulse wheel is damaged, the
engine will have to be disassembled down to the crankshaft
to
reolace the wheel.
- Make certain ignition has been turned off.
- Raise car and support in a safe manner.
WARNING -
Make sure the car is stable and well supported at all times.
Use a professional automotive lift orjacltstands designed for
the ouroose.
A floor iaclc is not adequate support.
- Remove under engine splash guard
4 Working underneath starter:
Cut off wire tie securing crankshaft speed sensor harness
connector (arrow) to sensor.
* Disconnect harness connector.
4 Remove sensor mounting fastener (arrow) and remove sen-
sor from cylinder block.
- Installation is reverse of removal, noting the following:
Use a new O-ring when installing sensor.
Be sure wiring is routed in same orientation.
Secure sensor using new wire ties.
Use scan tool to read out and clear ECM fault memory.

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121-1
121 Battery. Starter. Alternator
General ........................... .I2 1.2
Special tools ........................ .I2 1.2
Engine electrical system ............... .I2 1.2
Battery Safety Terminal ............... .I2 1.3
Warnings and cautions ................. 121 -4
Battery ............................ 121-5
Battery testing ...................... .I2 1.5
Hydrometer testing ................... .I2 1.5
Battery open-circuit voltage test ......... .I2 1.6
Battery load voltage test ................ 121 -6
Closed-circuit current measurement ..... .I2 1.7
Battery charging ...................... 121 -9
Battery safety terminal, replacing ......... 121-9
Alternator (generator) ............. .I2 1.10
Alternator. basic .................... .I2 1.11
Alternator with multi-function
control (MFR)
...................... .I2 1.11
Water-cooled alternator ............... 121 -12
Charging System Troubleshooting . 121-12
Charging system quick-check .......... 121-13
Charging system. checking ............ 121-13
Alternator. removing and installing
(6-cylinder engine)
.................. 121 -1 5
Alternator. removing and installing
(M62 engine. air cooled)
.............. 121-16
Alternator. removing and installing
(M62 TU engine. water cooled) ......... 121-1 8
Starter ........................... 121 -1 9
Starter troubleshooting ............... 121 -1 9
Starter. removing and installing
(6-cylinder engine)
.................. 121-20
Starter. removing and installing
(V-8 engine)
........................ 121 -21
Solenoid switch. removing and installing . . 121-23

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- -
Battery, Starter, Alternator
This section covers the battery, alternator, starter and associ-
ated components of the electrical system.
Troubleshooting information
forthese components isfound in
Table a. Battery, alternator and starter troubleshooting.
For additional electrical troubleshooting information, see
600 Electrical System-General.
Special tools
4 Automotive digital multimeter
CAUTION-
Only use a digital multirneter when testing automotive electri- I) cal components.
4 Closed-circuit current measurement adaptor
(Tool No.
BMW 61 2 300)
Engine electrical system
The alternator and starter are wired directly to the battery. To
prevent accidental shorts that might blow a fuse or damage
wires and electrical components, always disconnect the
negative
(-) battery cable before working on the electrical
system.
Various versions of alternators, voltage regulators, starters,
and batteries are used in
E39 cars. Replace components ac-
cording to the original equipment specification.

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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.

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.-. .
Battery, Starter, Alternator
Warnings and cautions
WARNING -
Wear goggles, rubber gloves, and a rubber apron when
working around the battery or battery acid (electrolyte).
Battery acid contains sulfuric acid and can cause skin
irritation and burning.
If acid is spilled on your skin or
clothing, flush the area at once with large quantities of
water. If electrolyte gets into your eyes, flush them with
large quantities of clean water for several minutes and
call a physician.
Batteries that are being charged or are fully charged
give off explosive hydrogen gas. Keep sparks and open
flames away. Do not
smoke.
CA UTIOI\C
Only use a digital multimeter when testing automotive elec-
trical components.
. If a repair procedure specifies disconnecting the bat-
tery, follow the instruction for safety reasons.
Prior to disconnecting the battery, read the battery dis-
connection cautions in
001 General Cautions and
Warnings.
Models with MS43 engine management: Allow at least
3 minutes to elapse after turning ignition ley to OFFpo-
sition before disconnecting battery. This willallow sum-
cient tinie to complete the DMJL (fuel tank pressure)
test
* Disconnecting the battery cables may erase fault codes
stored in ECM memory.
Always disconnect the negative
(-) battery cable first
and reconnect it last. Cover the battery post with an in-
sulating material whenever the cable is removed.
Do not disconnect battery, alternator or starter wires
while the engine is running.
0 Never reverse the battery cables. Even a momentary
wrong connection can damage the alternator or other
electrical components.
Do not depend on the color of insulation to tell battery
positive and negative cables apart. Label cables before
removing.
The slide-tilt sunroof may fail to function properly
after
disconnecting and reconnecting the battery. Reinitial-
ize sunroof as described in 540 Sunroof.

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Battery, Starter, ~iternatorl
The battery is mounted in the right side of the luggage com-
partment, concealed behind a trim panel. Battery capacity is
determined by the amount of current needed to start the vehi-
cle and by the amount of current consumed by the electrical
system. This will vary from model to model.
BMW batteries are rated by
amperelhours (Ah) and cold
cranking amps (CCA) rating, which are listed on the battery.
The Ah rating is determined by the average amount of cur-
rent the battery can deliver over time without dropping below
a specified voltage. The CCA is determined by the battery's
ability to deliver starting current at
On F (-18" C) without drop-
ping below a specified voltage. Always replace the battery
with one having the same or higher ratings.
Battery testing
Battery testing determines the state of battery charge. On
conventional or low-maintenance batteries. the most com-
mon method of testing the battery is that
ofchecking the spe-
cific gravity of the electrolyte using a hydrometer. Before
testing the battery, check that the cables are tight and free of
- corrosion.
Hydrometer testing
Before hydrometertesting, load the battery with 15 amperes
for one minute. If the battery is installed in the vehicle, this can
be done by turning on the headlights without the engine run-
ning. The state of battery charge based on specific gravity
values are given in Table
b. Specific gravity of battery elec-
trolyte at
27" C (80°F).
The hydrometer indicates the specific gravity of the electro-
lyte. The more dense the concentration of sulfuric acid in the
electrolyte, the higher the state of charge
NOTE-
Electrolyte temperature affects hydrometer reading. Checlc
the electrolyte temperature with a thermometer. Add 0.004 to
the hydrometerreading
forevery 6°C (10°F) that the electro-
lyte is above 27°C
(80°F). Subtract 0.004 from the reading
forevery 6°C (10°F) that the electrolyte is below27"C
(80°F).

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.
Battery, Starter, Alternator
Table b. Specific gravity of battery electrolyte at 27°C (80°F)
Specific gravity State of charge
1.265 Fully charged
1.225 75% charged
1.190 50% charged
1.155 25% charged
1.120 Fully discharged
if the specific gravity is at
orabove 1.225, butthe battery lacks
Dower for
startinq, determine the battew's service condition
with a load volta& test. if the average specific gravity of the
six cells is below 1.225, remove the battery from the luggage
compartment and recharge.
Battery open-circuit voltage test
Before testing, load battery with 15 amperes for one minute
with battery load-tester or turn on headlights for about one
minute without engine running. Connect digital voltmeter
across battery terminals. Open-circuit voltage levels are giv-
en in Table
c. Open-circuit voltage and battery charge.
If open-circuit voltage is
OK but battery still lacks power for
starting, perform a load voltage test.
If open-circuit voltage is
below 12.4 volts, recharge battery
and retest.
Table c. Open-circuit voltage and battery charge
Open-circuit voltage State of charge
12.6 V or more
12.4 V
12.2v
12.0 v
Fully charged
75% charged
50% charged
25% charged
11.7Vorless Fully discharged
Battery load voltage test
A battery load tester is required for a load voltage test. The
test is made by applying a high resistive load to the battery
terminals and then measuring battery voltage. The battery
should be
fully charged forthe most accurate results. The bat-
tery cables must be disconnected before
malting the test. Re-
place the battery if the voltage is below that listed in Table d.
Battery load test
- minimum voltage.

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Battery, Starter, ~lternatorl
WARNING-
Always wear protective goggles and clothing when perform-
ing a load test.
Table
d. Battery load test - minimum voltage
Ambient temperature Voltage*
27
" C (80" F) 9.6 V
-I 8' C (0"
F) 8.5 V
* Measure
after applying a 200 amp load for 15 seconds.
Closed-circuit current measurement
If the vehicle battery is discharged for an unknown reason,
perform a closed-circuit current measurement as the first test.
For diagnostic purposes, it is important to not disconnect the
battery. Disconnecting the battery may reset a faulty control
unit, preventing proper diagnosis.
The following test is generally completed overnight using a
multimeterwith a closed circuitcurrent measurement adaptor
with a recording function
- Check that battery voltage is 12 volts or higher. If lower,
recharge battery.
- Switch off electrical consumers (interior lights, telephone,
aftermarket equipment, or others).
- Open luggage compartment and remove battery trim panel.
Use screwdriver to lock latch on trunk lid or hatch, simulating
closed luggage compartment. Close other doors.
- Open driver's door, then close it, simulating driver entering
vehicle.
- Switch ignition to RUN position for at least five seconds, then
turn ignition to OFF position. This simulates driving vehicle.
- Open and close driver's door, simulating driver leaving
vehicle.
- Lock car and arm alarm.
- Wait at least 16 minutes for consumer cut-off.