1998 BMW 528i troubleshooting

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120 lgnition System
...................... General
Special tools ...................
Warnings and cautions ...........
Engine management .............
................. lgnition system
Ignition system. troubleshooting
....
... Oscilloscope diagnostic diagrams
................ Misfire detection
............. Ignition System Service 120-9
.................... Ignition firing order 120-9
.............. Disabling ignition system 120-10
................... Checking for spark 120-1 0
lgnition coil assembly.
................. testing and replacing 120-1 0
.............. Crankshaftspeedsensor 120-12
............. Camshaft position sensors 120-1 4
...................... Knocksensors 120-16

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Ignition System
This repair group covers component troubleshooting and re-
placement information for the ignition system.
When diagnosing engine management problems, including
on-board diagnostics (OBD
11) fault code analysis, also refer
to these repair groups:
* 130 Fuel Injection
* ELE Electrical Wiring Diagrams
OED On-Board Diagnostics
Special tools
System diagnosis and testing of the ignition system requires
special test equipment.
4 LED test light
(Tool No. Baum
1 1 15)
4 Automotive digital multimeter
4 Primary voltage test harness
(Tool No. BMW 12
7 020)
-
4 Secondary voltage test harness
(Tool No. BMW 12
7 030)

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120-6
lgnition System
lgnition system, troubleshooting
Troubleshooting ignition system faults should begin with an
interrogation of the On-Board Diagnostics (OBD
II) system.
The OBD
II system detects ignition system misfire and other
related faults. When faults are detected, the OBD
II system
stores a Diagnostic Trouble Code (DTC) in the Engine Con-
trol Module (ECM) along with other pertinent fault information.
4 In addition, the Malfunction Indicator Light (MIL) will come on
if an emissions related fault is detected. Additional OBD
II in-
formation, including a DTC lookup table, can be found in
OED On-Board Diagnostics.
NOTE-
BMWmodels covered in this manual were equipped with one
of three versions of
MIL warning lights (as shown).
Misfire detection
Engine m~sfire in one or more cylinders, may be caused by a
var~ety of malfunctions in various subsystems. The OBD II
system ~ncorporated into the engine management systems is
des~gned to detect and warn of misfire faults during englne
operat~on. See OED On Board Diagnostics.
WARNING -
lgnition misfires can cause high hydrocarbon exhaust emis-
sions andcatalytic converter damage. For this reason, if a se-
vere misfire is detected, the fuel injector
will be turned off to
the specific cylinder and the
MIL will be illuminated. A misfire
may also produce an overheated catalytic converter, which
can be a fire hazard.
Oscilloscope diagnostic diagrams
One way to diagnose a faulty coil is to use an oscilloscope to
analyze spark quality with the engine running.
See Table b. lgnition secondary voltage diagnostics for
list of common ignition
coil voltage faults and related causes.

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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
Water-cooled alternator
The water-cooled alternator, used on 1999 and later M62 TU
engines, is a sealed unit housed inside the engine block wa-
ter jacket. It is cooled via the engine cooling system. It is a
"brushless" sealed unit that cannot be serviced. Maintaining
consistent alternator temperatures increases the life span of
the alternator, and elimination of the alternator cooling fan re-
duces alternator noise
significantly.
The M62 TU water-cooled alternator incorporates load start
reduction. This function is intended to shorten the duration of
engine starting, particularly at low ambienttemperatures. The
current load is limited to
20 amps during starting in order to re-
duce alternator braking torque on the engine. Following the
current limiting phase, full power output is then progressively
reached.
Charging system diagnostics requires special test equip-
ment. If the test equipment is not available, charging system
fault diagnosis can be performed by an authorized
BMW
dealer or other qualified repair shop. See Table a. Battery,
alternator and starter troubleshooting for general electri-
cal component troubleshooting.
Before checking the alternator, make sure the battery is fully
charged and capable of holding a charge. Check that the bat-
tery terminals are clean and tight and the alternator drive belt
is properly tensioned and not severely worn.
NOTE-
Some model require up to 15 second to reacli full alternator
output.
CA UTIOG
If the charge indicator light in the instrument cluster remains
on, the charge warning circuit in the instrument cluster may
be faulty. Check that the ground lead is securely
affached to
the grounding stud on the cylinder head
(A). Replacing the
instrument cluster before repairing the ground lead will both
damage the instrument cluster and cause the failure to
reoccur.

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Battery, Starter, Alternator
- Installation is reverse of removal, noting the following:
Replace alternator rubber sealing O-ring.
* Fill and bleed cooling system as described in 170 Radiator
and Cooling System.
Tightening torques
Fan clutch to coolant pump
with
BMW special tool 11 5 040 30 Nm (22 ft-lb)
without
BMW special tool 11 5 040 40 Nm (29 ft-lb)
Terminal 30 (Bc) wire to alternator (ME) 13 Nm (10 ft-lb)
STARTER
Starter troubleshooting
Typical starter wiring terminal identification is shown. Large
wire at terminal
30 (not shown in photo) is direct battery volt-
age. Smaller wire at terminal
50 operates starter solenoid via
ignition switch.
If starter turns engine slowly when ignition is in start position:
Check battery state of charge.
Inspect starter wires, terminals, and ground
connectlons
for good contact. In particular, make sure ground connec-
tions between battery, body and
englne are completely
clean and tight.
If no faults are found, starter may be faulty and should be
replaced.
- If starter fails to operate, check EWS (drive-away protection
system). Try another ignition key.
If no faults can be found,
have the EWS system checked using
BMW scan tool equip-
ment.
Checkclutch pedal operated
starter lock-out switch or gear
position switch (automatic).
NOTE-
* A factory-installed drive-away protection system, also re-
ferred to as
EWS, is used on E39 cars. This system pre-
vents operation of the starter if a specially coded ignition
key is not used.
On cars with automatic transmission, the transmission
gear position switch signals
EWS to prevent the engine
from starting in gear positions other than PARK or NEU-
TRAL.
On cars with manual transmissions, a starter immobiliza-
tion switch
at the clutch pedal is used to prevent the starter
from operating unless the clutch pedal is pushed fully to
the floor.