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OBD-3
On-Board
~iactnosticsl
Additional MIL information:
A fault code is stored within the ECM upon the first
occurrence of a fault in the system being checlted.
Two complete consecutive drive cycles with the iault
present illuminate the MIL. The exception to the two-fault
requirement is a catalyst-damaging fault, which illuminates
the MIL immediately.
If the second drive cycle was not complete and the fault
was not checked, the ECM counts the third drive cycle as
the next consecutive drive cycle. The MIL illuminates
if the
system is checked and the fault is still present.
Once the MIL is illuminated, it remains illuminated until the
vehicle completes three consecutive drive cycles without
detecting a fault.
0 An existing fault code is cleared from memory
automatically when the vehicle completes
40 consecutive
drive cycles without the fault being detected.
In order to automatically clear a catalyst-damaging fault from
memory, the condition underwhich the fault occurred must be
evaluated for 80 consecutive drive cycles without the fault
reoccurring.
A generic scan tool connected to the BMW data link
connector (DLC) or OBD
I1 plug can display diagnostic trouble
codes (DTCs), along with the conditions associated with the
illumination of the MIL. Using a more advanced or
BMW-
dedicated scan tool, additional proprietary information is
normally available.
Scan tool and scan tool display
The complexity of the OBD I1 system requires that all
diagnostics begin by connecting a scan tool to the vehicle.
Aftermarltet scan tools can be connected to either the 16-pin
OBD
I1 plug or the 20-pin BMW DLC in the engine
compartment
(ii installed). Data from the OBD II plug may be
limited, depending on scan tool and vehicle.
OBD
I1 standards reouire that the 16-oin OBD I1 oluo be
located within three
(3) feet of the driier and not're&ire any
tools to access.
Starting with June 2000 production, the 20-pin BMW DLC,
previously located in the engine compartment, was
discontinued. Diagnostic, coding and programming functions
are incorporated into the OBD
II plug, located under left side
of dashboard.
On cars built up to 06
/ 2000: when accessing emissions
related DTCs through the 16-pin OBD
I1 plug, malte sure the
BMW 20-oin DLC
caD is installed.

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- -
On-Board Diagnostics
Professional diagnostic scan tools available atthe time of this
printing include the BMW factory tools
(DISplus, GTI,
MoDiC) and a small number of aftermarket BMW-specific
tools. See
020 Maintenance.
In addition to the professional line of scan tools, inexpensive
generic OBD
II scan tool software programs and handheld
units are readily available. Though limited, they are
nonetheless powerful diagnostic tools. These tools read live
data streams and freeze frame data as well as a host of other
valuable diagnostic data.
Diagnostic monitors
Diagnostic monitors run tests and checks on specific
emission control systems, components, and functions.
A complete drive cycle is requiredforthe tests to bevalid. See
Drive cycle in this repair group. The diagnostic monitor
signals the
ECM of the loss or impairment of the signal or
component and determines if a signal or sensor is faulty
based on
3 conditions:
* Signal or component shorted to ground
Signal or component shorted to
B+
Signal or component missing (open circuit)
The OBD
II system monitors all emission control systems that
are installed. Emission control systems vary by vehicle model
and year. For example, a vehicle may not be equipped with
secondary air injection, so no secondary air readiness code
would be present.
OBD
II software monitors the following:
Oxygen sensors
Catalysts
Engine misfire
- Fuel tank evaporative control system
Secondary air injection Fuel system
Oxygen sensor monitoring. When driving conditions allow,
response rate and switching time of each oxygen sensor is
monitored. The oxygen sensor heater function is also
monitored. The OBD
II system differentiates between
precataylst and post-catalyst oxygen sensors and reads each
one individually. In order
forthe oxygen sensor to be
effectively monitored, the system must be in closed loop
operation.

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OBD-6
On-Board Diagnostics
Fuel system monitoring. This monitor looks at the fuel
delivery needed (long
/short term fuel trim) for proper engine
operation based on programmed data. If too much or not
enough fuel is delivered over a predetermined time, a DTC is
set and the MIL illuminates.
Fuel trim refers to adiustments to base fuel schedule.
Lono- ., term fuel trim refers to gradual adjustments to the fuel
calibration adjustment as compared to short term fuel trim.
Long term fuel trim adjustments compensate for gradual
changes that occur over time.
Fuel system monitoring monitors the calculated injection time
(ti) in relation to enginespeed, load and precatalyticconverter
oxygen
sensor(s) signals.
Using this data, the system optimizes fuel delivery for all
engine operating conditions.
Evaporative system monitoring. This monitor checks the
the fuel storage system and related fuel lines for leaks. It can
detect very small leaks anywhere in the system.
A leak detection unit (LDP or DMTL) is used to pressurize the
evaporative control system on a continuous basis (as the
drive cycle allows) and to
check system integrity.
Drive cycle
The OED II drive cycle is an important concept in
understanding OBD
II requirements. The purpose of the drive
cycle is to run ail of the emission-related on-board diagnostics
over a broad range of driving conditions.
A drive cycle is considered complete when all of the
diagnostic monitors have run their tests without interruption.
~ora drive cycle to be initiated, the vehicle must be started
cold and brought up to
1 60°F and at least 40°F above its
original starting temperature.
Readiness codes
Inspection/maintenance (I/M) readiness codes are mandated
as part of OBD
II. The readiness code is stored aftercomplete
diagnostic monitoring of specified components and systems
is carried out. The readiness code function was designed to
prevent manipulating an
I/M emission test procedure by
clearing faults codes or disconnecting the ECM or battery.

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On-Board Diagnostics
Readiness codes indicate whether the OED Ii system is
actually ready to monitor the various emission control
systems on the vehicle. The vehicle must complete a drive
cycle to set readiness codes. The code is binary:
0 for ready
1 for not ready
f
4 The parameters which are monitored for readiness are:
llM readiness codes
1. Catalyst efficiency
2. Catalyst heating
3. Fuel tank evaporative control
4. Secondary air injection
5.
NC refrigerant
6. Oxygen sensors
7. Oxygen sensor heaters
8. Exhaust gas recirculation
Readiness codes are set to 1 (not ready) in the following
cases:
~9~~.f~[<+t~t~p:,~;:#j~~{]~y~ ,,... , , 8701Dbd001
The battery or ECM is disconnected.
When
all zeros are displayed, the system has established
DTCs are erased after completion of repairs and a drive
cycle is not completed.
readiness. Readiness codes
can be displayed using BMW
and aftermarket scan tools.
An
OED II scan tool can be used to determine IIM readiness.
Diagnostic trouble codes (DTCs)
SAE standard J2012 mandates a 5-digit diagnostic trouble
code (DTC) standard. Each digit represents a specific value.
Emission related DTCs
start with the letter P for power train.
When the engine service
light (MIL) is illuminated it indicates
that a DTC has been stored.
DTCs are stored as soon as they occur, whether or not the
engine service light illuminates.
DTCs store and display a time stamp.
DTCs record the current fault status: Present, not currently
present, or intermittent.

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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

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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

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WARNING
Your common sense, good
judgement, and general alertness are
crucial lo sale and
successlul service
work. Belore attempling any work on
your BMW, be sure to read 001
General Warnings and Cautions
and lhe copyright page
a1 llle Iron1 01
the manual. Review lliese warnings
and cautions each time you prepare
lo work on your
BMW Please also
read any warnings and
caulions lhal
accompany the procedures In !he
manual.
Component locations
see Electrical system
Compression test
113-5
Compressor see
AlC
Condenser see
AlC
Constant velocity (CV) joint
see Maintenance
see also
Driveshall
see also Drive axles
Consumer cutoff
600-10
Control arm see Front suspension
see also Rear suspension,
suspension arms
Coolant (antifreeze) see Maintenance
see also Cooling system
Coolant pump
see Cooling system Cooling system
coolant bleeding
170-14 6-cylinder engine, draininglfilling
170-10
V-8 engine, draininglfilling 170-12
coolant pump 170-3
6-cyiinder engine, replacing 170-1 9
V-8 engine, replacing 170-20 cooling fan 170-4
viscous ciutch fan, removingi
installing 170-14
electric fan, removlngiinstailing 170-1 5
expansion tank, removinglinstalling
170-22
electrically heated (ciiaracterislic
map) therrnostat 170-4
radiator, removinglinstaliing 170-22
service
see Maintenance
therrnostat 170-16
transmission fluid heat exchanger
170-5 troubleshooting 170-7
combuslion leal( test 170-10
pressure test
170-9
Crankshaft oil seals
iront
117-6
rear 11 9-6
Crankshaft speed sensor
see Ignition syslem
Crash sensor
see
Airbag system (SRS), side-impact
airbag crasii sensor
Cruise control clutch switch 612-9
CV joint
see Maintenance
see also Driveshalt
see also Drive axles
CV joint boot
see Maintenance
see also Drive axles
Cylinder head removinglinslaliing
M52 engine 113-8
M52 TU / M54 engine 113-22
M62 engine 113-56
Cylinder head and valvetrain
hydraulic lifters, checking and
replacing
116-7 leak test 116-5 valves 11 6-56
see
alsocylinder head Dashboard
513-7
Deck
lid
seeTrunk lid
Diagnostic monitors
OED-4
Diagnostic trouble codes
(DTCs)
080-7
Digital multimetel
010-17
Differential see Final drive
DLC (data
link connector) 020-4, OED-4
DME (digital motor electronics)
see
130 under appropriate fuel
injection system
see also ignition system
DM-TL (detection module-tank leak)
see
Fuel lank, leak deteclion unit
Drive
belts
see Maintenance
Dome light
seeLighls, interior lights
Door
door
check, replacing 411-4
hinge adjustment 41 1-5
loci(
see Door lock see also Central locking
removinglinslaliing 41
1-2
panel, removinglinstaliing 41 1-7 window
see Door window
Door
check
see Door
Door
handle
see Door lock
Door glass
see Door window
Door
lock
handles and loci(s 515-16
see also Central locking
Door
molding
510-13
Door panel see Door

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4 INDEX
Door window anti-trap
512-4 convenience openinglclosing 512.4
regulator and motor 512-1 1
service
512-5 switches 512-3
see also Switches
Double
VANOS see VANOS
Drive
axle
CV joint 331-15 CV joint boot 331-15
rernovinglinstalling 331-14
Drive belt
see Maintenance
Driveabiiity troubleshooting
100-4
Driveaway protection
see EWS (eiectronic immobilization)
Driveshaft aligning
260-7
center bearing, replacing 260-12 CV joint, replacing 260-14
itex-disc, replacing 260-1 1
iront centering guide, replacing 260-13
rernovinglinstailing 260-6
lroubleshooting 260-3
U-joint 260-3
DSC
see Braires
DTC (diagnostic trouble code)
OBD-8
DWA
see Anti-theft alarm
ECM (engine control module)
see 130 under appropriate
iuei
injection system
ECT (engine coolant temperature)
sensor see 130 under appropriate
iuei
injection system
EDK adaptation
130-69
MS 43.0 130-35
EHC see Electronic iieigiit control (EHC)
Electric cooling fan
see Cooling system, cooling
fan
see also Cooiing system, eiectric fan
Electrical switches
see Switches
Electrical system abbreviations
600-14 bus System 600-4
component location table 610-3
components
photos
610-36
Sport Wagon 610-81 engine 121-2
troubleshooting 600-15
voltage and polarily 600-5 wire color codes 600-12
wiring diagrams 600-12
Electrical wiring diagrams
ELE-1
Eiectricaliy heated thermostat
(characteristic map)
170-4
Eiectronic height control (EHC)
300-8, 330-44
Eiectronic immobilization
see EWS (electronic immobilization)
Eiectronics box
(E-box)
610-37
Emergencies
010-18
Emergency brake see
BraBes, parking brake Engine
see also Cylinder head and valvetrain
applications
100-2
compression, testing 113-5
cooling see Cooiing system
crankshaft front oil seai
see Crankshaft oil seals
cyiinder leak-down test 113-8
diagnostic testing 113-1
drive belts
see Maintenance
driveability troubleshooting
100-4
engine management systems 100-2
see also Ignition
see also Fuel injection
fuel supply
130-6
ground connections 100-5
see also 61 0 identilying ieatures 100-3
lubrication svstem
see
~ubricetion system
mount
on-board diagnostics
OBD-I
oxygensensor
see Fuel injection
see also Exhaust system
Dreventive maintenance
see Maintenance
removal/installation
Engine control module (ECM)
see 130 under appropriate iuel
injection system
Engine cooiant temperature (ECT)
sensor see 130 under appropriate iuel
injection
system
Engine cooling fan
see Cooiing system, electric fan
Engine hood
41
0-6 raising to service position 410-6
Engine troubleshooting
see Engine, driveability troubleshooting
EVa~oratiVe control svstem
160-3 see also 130 under aDDroDriate iuel
injection system
Evaporator see
NC
Evaporator temperature sensor see
NC