2000 BMW 540i Light

Downloaded from www.Manualslib.com manuals search engine
I lgnition System
4 Normal combustion period at idle.
4 Normal oscilloscope pattern for ignition system at idle.
15. 15
4 lgnition voltage peaks at idle.
1. Normal ignition peaks.
2. Downward peak (arrow) is shortened (ignition coil is
defective).
3. Downward peak (arrow) is missing completely (ignition
coil is defective).
4 Defective ignition coil.
1. Short spark period.
2. The spark voltage line (arrow) is very slight
< Defective ignition coil.
1. Normal combustion period.
2. Absence of spark voltage line (arrow).
(r+~+~+~(.~i+~/.~~itlt~~(tit~lii~~jt~~~i~ittiii~l IW 10 ED 10 (0 ID U 10 11 70 0 sa,ma,
2 . 15 - .
5 - - - 0
30
.
.
20 .
I0 - -
0
iiiCi;kiW*huiMwiritil~tiii 110 10 00 ro w M A, 30 2" *:,:mu

Downloaded from www.Manualslib.com manuals search engine
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.

Downloaded from www.Manualslib.com manuals search engine
ignition System
Crankshaft speed sensor, replacing (M62 and M62TU
engines)
The crankshaft speed sensor reads a toothed pulse wheel
mounted on the flywheel.
If the Engine Control Module(ECM)
does not receive an impulse signal from the crankshaft speed
sensor during
cranking, the engine will not start. If the OBD II
system misfire detection protocol detects a catalyst damag-
ing fault due to a malfunction in the crankshaft speed sensor
components, the Check Engine light (Malfunction
Indicator
Light or MIL) will be Illuminated.
4 The crankshaft speed sensor (arrow) is mounted in the right
lower side of the bell housing.
- Remove speed sensor by disconnecting electrical harness
connector and unbolting sensor from bell housing. Do not
discard shims, if present.
- Installation is the reverse of removal. Clean mounting surface
before installing new sensor, and install shims, if present.
< If the flywheel was replaced, the speed sensor must be
checked for correct installation depth.
* Crank engine in direction of rotation using crankshaft bolt
until a full pulse tooth is centered in the opening for the re-
moved speed sensor.
Measure depth ro top of tooth from speed sensor p~lse
generator mounting s~rface on transmission.
4 Measure length of pulse generator from mounting surface to
end (A).
- Subtract length of pulse generator (A) from distance to pulse
tooth from mounting area on transmission. This measure-
ment is the gap between the pulse sensor and flywheel. Use
shims available from BMW to increase gap as needed to
reach specification.
Pulse sensor
gap
End of sensor to flywheel teeth 0.55 + 0.2 rnrn
(0.0217 t 0.008 in)

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
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).

Downloaded from www.Manualslib.com manuals search engine
.
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.

Downloaded from www.Manualslib.com manuals search engine
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.

Downloaded from www.Manualslib.com manuals search engine
121-8
/Battery, Starter, Alternator
NOTE-
Automatic transmission cars: ambershifier LED willgo out at
consumer cut-off.
4 Attach closed-circuit current measurement adaptor
(BMW special tool
61 2 300):
Connect red clamp (marked A -BATT (+)) to positive bat-
tery terminal.
Connect
black clamp (marked B -CHASSIS) to chassis
ground point.
NOTE-
Green LED will light up to indicate correct installation of
closed-circuit current measurement
adaotor.
< Connect blaclc clamp (marked B - BATT (-)) to negative bat-
tery terminal. Green
LED light will go out.
NOTE-
Any electrical overloading will be indicated at this point by
lighting the red
LED. If the red LED lights up, check the adap-
tor connections.
< Set multimeter (A) to 10 amp measuring range and connect
it to adaptor.
NOTE -
Set multimeter to record average readings.
Ifpossible, turn offpowersaving features of multimeter
which prevent a long term (overnight) test by automatically
powering down
meter.
- Disconnect battery ground strap (B) at chassis mounting
point.
- Measure closed-circuit current using multimeter.
- Typical average closed-circuit current for E39 vehicles is
40 mA. Readings over 50 mA must be further investigated.