Ignition system BMW 323i 1995 E36 User Guide

100-4
ENGINE-GENERAL

'



TEMP

PRECAT



POST
CAT



OXYGENSENSOR
HEATING

#
.
THROTTLE
POSITION



FUEL
INJECTOR
CONTROL
(SEQUENTIAL)

OPERATING
POWER



00

CAMSHAFT
POSITION
SENSOR

ECM



I
MAIN
GROUND

RELAY



J_



-



AC
COMPRESSOR
RELAY
CONTROL

TERMINAL
15

MEMORY
POWER
FUEL
PUMP
RELAY
CONTROL
AUX
GROUND
P

CRANKSHAFT
POSITION
dESENSOR

INTAKE
AIR

ENGINE
COOLANT
TEMP

FUEL
TANK
PRESSURE
SENSOR

S-EML
S-MSR

ASC
S-ASC

VEHICLE
SPEED

LOW
FUEL
LEVEL

A/C
SWITCH
ON
(AC)
E36
IHKA
COMPRESSOR"ON"

SIGNAL
(KO)

INDIVIDUAL
SERIAL
NUMBER

MS41
.1

SECONDARY
AIR
1NJECTION
AIR
PUMP®
RELAY
CONTROL

IDLE
CONTROL
VALVE



'M

FUEL
INJECTION
(TI)

ENGINE
SPEED
(TD)

Fig
.
5
.



Siemens
MS
41
.1
OBD
II
engine
management
systemusedon
1996
and
later
M52
engines
.

GENERAL

IGNITION
COILS
CONTROL

L
r"Q
if~
CIYVFIYC



CHE
AMP
CONTROL
ENGINE

THROTTLE
POSITION

6

ECM
RELAY
CONTROL

ASC

THROTTLE
..
:
.
.
..
-11



1Q\\\
POTENTIOMETER
POWER

CAN



TCM
II



SCAN
(DES
;
ER

DIAGNOSIS

OBD
II
I
II

GENERIC
SCANTOOL



0012596

ignition

Table
b
.
Engine
Management
Systems



engine
has
high
mileage
.

Engine



1
System

4-cylinder
engines
M42
(1992-1995)



Bosch
DME
Ml
.7
M44
(1996-1998)



Bosch
DME
M5
.2
(OBD
II)

6-cylinder
engines
M50
(1992)



Bosch
DME
M3
.1
M50
VANOS
(1993-1995)



Bosch
DME
M3
.3
.1
M52
(1996-1998)



Siemens
MS41
.1
(OBD
II)
S50US
(1995)



Bosch
DME
M3
.3
.1
S52US
(1996-1998)



Siemens
MS41
.1
(OBD
II)

Both
the
4-cylinder
and
6-cylinder
engines
use
a
distributor-

less
ignition
system
with
individual
ignition
coils
for
each
cylin-

der
.

FuelDelivery

Pressurized
fuel
from
the
in-tank
fuel
pump
is
injected
via

solenoid-type
fuel
injectors
.
The
ECM
controls
the
opening

and
closing
of
the
injectors
by
switchingthe
ground
side
of

each
injector
circuit
.
The
exact
amount
of
fuel
injected
is
de-

termined
by
the
amount
of
timethe
injectors
are
open
.

Cooling
System

Whenever
the
engine
is
running,
acoolant
pump
circulates

coolant
through
the
engine
and,
if
either
heater
control
valves

are
open,
through
the
heater
core
in
the
passenger
compart-

ment
.
The
coolant
absorbs
excess
heat
and
carries
it
to
the
ra-

diator
where
it
is
transferred
into
the
passing
airstream
.
A

thermostat
controls
the
flow
of
coolant
through
the
radiator

based
on
engine
temperature
.

Lubrication
System

The
lubrication
system
is
pressurized
whenever
theengine

is
running
.
The
oil
pump
draws
oil
through
a
pickup
in
the
bot-

tom
of
the
oil
pan,thenforces
it
through
a
replaceable
oil
filter

and
finto
the
engine
oíi
passages
.

On
4-cylinder
engines,
the
oil
pump
is
mounted
to
the
front

engine
cover
.
On
6-cylinder
engines,thechain-driven
oil

pump
is
bolted
to
the
bottom
of
the
cylinder
block
.

A
pressure
relief
valve
limits
the
maximum
system
pres-

sure
.
A
bypass
valve
prevents
the
oil
filter
from
bursting
and

insures
engine
lubrication
should
the
filter
become
plugged
.

See
119
Lubrication
System
for
additional
information
.

ENGINE-GENERAL
100-
5

Various
versions
of
DME
systems
are
usedon
thecars
cov-



MECHANICAL
TROUBLESHOOTING
ered
by
this
manual
.
See
Table
b
.
Each
system
is
highly
adaptive
to
compensate
for
things
suchasengine
wear
and



When
troubleshooting
an
engine
that
fails
to
start
or
runs
vacuum
leaks
.



poorly,
first
check
its
mechanical
condition-particularly
if
the

Warnings
and
Cautions

For
personal
safety,
as
well
asthe
protection
of
sensitive
electronic
components,
the
following
warnings
and
cautions
must
be
adhered
to
during
all
troubleshooting,
maintenance,
and
repairwork
.

WARNING
-

"
The
ignition
system
produces
high
voltages
that
can
be
fatal
.
Avoid
contact
with
exposed
termi-
nals
anduse
extreme
caution
when
working
on
a
car
with
the
ignition
switched
on
or
the
engine
running
.

"
Do
not
touch
or
disconnect
any
high
voltage
ca-
bles
from
the
coil,
distributor,
orspark
plugs
while
the
engine
is
running
or
being
cranked
by
the
starter

"
Connect
and
disconnect
the
engine
manage-
ment
system
wiring
and
test
equipment
leads
only
when
the
ignition
is
switched
off
.

"
Gasoline
is
highly
flammable
and
its
vapors
are
explosive
.
Do
not
smoke
or
work
on
a
car
near
heaters
or
other
fire
hazards
when
diagnosing
and
repairing
fuel
system
problems
.
Have
a
fire
extínguisher
available
in
case
of
an
emergency
.

"
Disconnecting
the
battery
may
erase
fault
code(s)
stored
in
control
module
memory
.
Using
special
BMW
diagnosnnc
equipment,
check
for
fault
codes
prior
to
disconnecting
the
battery
cables
.
If
the
Check
Engine
lightis
illuminated,
see
On-

Board
Diagnostics
(OBD)
forfault
code
infor-
mation
.
If
any
other
system
faults
havebeen
de-tected
(indicated
byan
illuminated
warning
light),
see
an
authorized
BMW
dealer
.

CAUTION-

"
Prior
to
disconnecting
the
battery,
read
the
bat-
tery
disconnection
cautions
gíven
at
the
front
of
this
manual
on
page
viii
.

"
Do
notconnect
any
test
equipment
that
delivers
a
12-volt
power
supply
to
terminal15
(+)
of
the
ignition
coil
.
The
current
flow
may
damage
the

ECM
.
In
general,
connect
test
equipment
only
as
specified
by
BMW,
this
manual,
or
the
equip-
ment
maker
.

"
Do
not
disconnect
the
battery
with
the
engine
running
.
Do
notrunthe
engine
with
any
of
the
sparkplug
wires
disconnected
.

MECHANICAL
TROUBLESHOOTING

100-6
ENGINE-GENERAL

Cylinder
compression,
checking

A
compression
tester
is
needed
to
make
a
compression
test
.

To
obtain
accurate
test
results,
the
battery
and
starter
must
be
capable
of
cranking
the
engine
at
250-300
rpm,
and
theen-

gine
should
be
at
normal
operating
temperature
.
Use
com-

pressed
air
to
clean
aroundthe
spark
plugs
before
removal
.

1
.
Disable
the
ignítion
system
by
removing
the
engine

management
system
main
relay
and
the
fuel
pump
re-
¡ay
.
See
Fig
.
6
.

WARNING
-

The
ignítion
system
produces
high
voltages
that
canbe
fatal
.
Avoid
contact
with
exposed
termínals
and

useextreme
caution
when
working
on
acar
wíth
the
ignítion
switched
on
or
the
engine
running
.

Fuel



DM
E
pump
main
re
ay



rel
ay
o
oa
ooa

.,
o00
oao

Fig
.
6
.



Engine
management
relays
in
power
distribution
box
inleft
rear
of
engine
compartment
.

CAUTION-

"
On
OBD
11
cars,
making
a
compression
test
may
causea
faultto
set
in
the
ECM
and
may
also
il-
luminate
the
Check
Engine
light
.
The
light
can
only
be
tumed
out
using
special
scan
tool
equip-
ment,using
eíther
the
BMW
specialservíce
tool
or
using
a
"generic"
OBD
11
scan
tool
.
Discon-
necting
the
battery
will
not
erase
the
fault
mem-
orynor
turn
outthe
light
.

0013034,

0012630

Fig
.
7
.



Remove
spark
plug
wires
from
spark
plugs
on
4-cylinder
en-
gine
using
special
tool
.
Tool
is
stored
under
cover
at
rear
of
cylinder
head
(arrow)
.

Fig
.
8
.



Remove
engine
cover
on
6-cylinder
engine
byprying
off
nut
covers
and
removing
nuts
(A)
.
Be
careful
not
to
let
rubber
in-
sulators
fall
off
as
cover
is
removed
(arrows)
.

4
.
On
6-cylinder
engines,
disconnect
the
harness
connec-
tors
from
the
ignítion
coils
by
lifting
the
retaining
clip
.

Remove
the
coil
mounting
nuts
andremove
the
six
coils
.
See
Fig
.
9
.
Remove
the
sparkplugs
.
"
Failure
to
remove
the
main
relay
or
attempting
to
disable
the
ignítion
system
by
other
methods
may
resultin
damage
to
the
engine
control
module
.



NOTE-

Used
sparkplugs
should
be
reinstalled
in
the
same
cyl-

2
.
On
4-cylinder
engine
:
Remove
plastic
engine
cover
from



inder
fromwhich
they
were
removed
.

top
of
cylinder
head
.
Disconnect
spark
plug
wires
and
re-
move
spark
plugs
.
See
Fig
.
7
.



5
.
Insta¡¡
the
compression
gauge
in
the
first
cylinder's

3
.
On
6-cylinder
engine
:
Remove
top
engine
coverby
pry-



spark
plug
hole,
tight
enough
to
form
a
good
seal
.

ing
off
nut
covers
and
removing
mounting
nuts
.
See
Fig
.
8
.

MECHANICAL
TROUBLESHOOTING

100-8
ENGINE-GENERAL

Symptom



1



Probable
cause
and
correctiveaction

1
.
Engine
will
not
start
or
run
.
Starter
cranks



a
.



No
fuel
reaching
engine
.
Check
forfuelin
tank
.

engine
at
normal
speed
.



Fuel
pump
notoperating
.
Repair
Group
160

b
.
No
spark
.
Check
ignition
system
.
Repair
Group
120

c
.
Incorrect
valve
timing
.
Check
timing
chain
.
Repair
Group
117

2
.
Check
Engine
warning
light
illuminated
.



a
.
DME
engine
management
system
self-diagnostic
fault
detected
.
Sea
an
authorized
BMW
dealer
or
other
qualified
shop
for
OBD
II
fault
code
diagnosis
.
See
also
On-
board
Diagnostics(OBD),
given
later
inthis
repair
group
.

3
.
White
exhaust
smoke
(steam)
.



a
.
Failed
cylinder
head
gasket
(probably
accompanied
bylowcompression
readings)
.

Replace
gasket
and
resurface
cylinder
head
if
necessary
.
Repair
Group
113
4
.
Blue-gray
exhaust
smoke
and
oily
spark



a
.
Contaminated
or
gasoline-diluted
engine
oil
.
Change
engine
oil
and
replace
oil
filter
.
plugs
.
Indicates
oii
burning
in
combustion
.



Repair
Group
020

b
.
Faulty
valve
guide
seals
or
valve
guides
.
Replace
valve
guide
oil
seals
or
overhaul
cylinder
head
.
Repair
Group
116

5
.
Pinging
or
rattling
when
under
load,



a
.
Ignition
timing
too
advanced
.
Ignition
knocksensors
faulty
(CheckEngine
light
traveling
uphill,
or
accelerating,
especially



illuminated)
.
Repair
Group
120fromlow
speeds
.
Indicates
pre-ignition
or



b
.
Fuel
octane
leve¡
toolow
.
detonation
.



c
.
Engine
running
too
hot
or
overheating
.
Check
cooling
system
.
Repair
Group
170

6
.
Light
metallic
tapping
that
varies
directly
with
engine
speed
.
Oil
pressure
warning
light
not
illuminated
.

7
.
Light
metallic
knock
that
varies
directly
with
enginespeed
.
Oil
pressure
warning
light
blinking
or
fully
illuminated
;
may
be
most
noticeable
during
hard
stops
or
cornering
.

8
.
Screeching
or
squealing
under
load
that



a
.
Loose,worn,
or
damaged
drive
belt
.
Inspect
belt(s)
.
Repair
Group
020
goesaway
when
coasting
.

9
.
Growling
or
rumbling
that
varieswith
engine



a
.
Remove
drive
belt(s)toidentifyfaulty
component
.
Check
for
play,
bearing
roughness,
rpm
.
Indicates
abad
bearing
or
bushing
in



and
loose
mountings
.
Refer
to
appropriate
repair
group
for
repair
procedures
.
an
engine-driven
accessory
.

DRIVEABILITY
TROUBLESHOOTING



On-Board
Diagnostics
(OBD)

On-Board
Diagnostics
is
incorporated
into
al¡
engine
man-



Two
generations
of
OBD
are
usedon
thecars
covered
by
agement
systems
used
on
the
cars
covered
by
this
manual
.



this
manual
:
Therefore,
checking
for
fault
codes
should
be
the
first
step
in
troubleshootinga
driveability
problem
.
For
additional
informa-



On-Board
Diagnostics
tion
on
engine
management
and
repair
see130
Fuel
Injec-
tion
.



"
1992-1995models
....
.
..
....
.
..
.......
OBD
I

"
1996-1998models
.
....
..
.
.
.
..
.
........
OBD
II

DRIVEABILITY
TROUBLESHOOTING

Tablec
.
Engine
Mechanical
Troubleshooting

b
.
Warped
or
cracked
cylinder
head
.
Resurface
or
replace
cylinder
head
.
Repair
Group
113

c
.
Cracked
cylinder
block
.
Replace
engine
or
short
block
.

c
.
Worn
piston
rings
.
Overhaul
or
replace
engine
.

d
.
Failed
cylinder
head
gasket
.
Replace
gasket
.
Repair
Group
113

d
.
Air/fuel
mixture
too
lean
(Check
Engine
light
illuminated)
.
Repair
Group
130

a
.
Valveclearances
excessive
.
Check
hydraulic
valve
adjusters
.
Repair
Group
116

b
.
Low
oil
pressure
orpossibly
defective
warning
light
circuit
.
Check
oil
pressure
andwarning
light
circuit
.
Repair
Group
119
c
.
Dirty
oil
.
Change
oil
.
Repair
Group
020
.

a
.
Low
oil
leve¡
.
Check
and
correct
oil
leve¡
.

b
.
Low
oil
pressure/worn
or
faulty
oil
pump
.
Oil
pump
pickup
restricted/clogged
.
Check
oil
pressure
.
Repair
Group
119

The
OBD
system
detects
emissions-related
engine
manage-
ment
malfunctions
and
tucos
on
the
Check
Engíne
lightin
the
in-
strument
cluster
.
TheCheck
Engine
light
will
stay
on
until
the
code(s)are
called
up
and
the
memory
is
erased
.
When
faulty
are
detected,
the
OBD
system
stores
a
Diagnostic
Trouble
Code
(DTC)
in
the
system
ECM
.
In
addition,
the
Check
Engine
warn-
ing
light
will
come
on
if
an
emissions-related
fault
is
detected
.

NOTE-

"
On
carswith
OBD
ti,
specialized
OBD
11
scan
tool
equipment
must
be
used
to
access
the
DTCs,
either
using
the
BMW
special
tool
ora
`generic"
OBD
11
scan
tool
.
See
130
Fuel
Injection
.

"
The
08D
11
fault
memory
(including
an
iiluminated
Check
Engine
light)
can
only
be
reset
using
the
spe-
cial
scan
tool
.
Removing
the
connector
from
the
ECM
or
disconnecting
the
battery
will
not
erase
the
fault
memory
.

Table
d
.
OBD
1
Fault
(Blink)
Codes

(1992-1995
modeis
only)

Graphic
representation
of
flashing
Check
Engine
light
fault
code
:
1221
5
Seconds
.
:-



2
.5~-

--05--

Fault
code
and
meaning



1
Corrective
action

Code
1216
:
Throttle
potentiometer

Code
1218
:
Output
stage,
group#1
(DME
3
.3
.ionly)

Code
1219
:
Output
stage,
group
#2
(DME
3
.3.1
only)

Code
1221
:
Oxygen
sensor
#1

Code
1224
:
Air
temperature
sensor
(NTC)

Code
1226
:
Knock
sensor
#2
(DME
3
.3
.1
only)

130

ENGINE-GENERAL
100-
9

2
.5
seconds,
then
go
off
for
2
.5
seconds
.
At
thispoint,
the
fault
codes
will
begin
to
flash
.
See
Table
d
.

If
more
than
one
fault
has
been
detected,
eachcode
will
be
separated
by
a2
.5
second
pause
.
When
al¡
fault
codes
havebeen
displayed,
there
will
be0
.5
second
flash
and
thenthe
light
will
remain
off
.
To
read
the
codes
again,
turn
the
key
off
and
then
on
again
.
Depress
theaccelerator
pedal
to
the
floor
five
times
quickly
(within
5
seconds)
.
The
codes
will
begin
to
repeat
.

On
cars
with
OBD
I,
fault
codes
can
be
read
by
turning
the



To
erase
the
fault
code
memory,
first
make
sure
the
fault

ignition
key
on
and
fully
depressing
theaccelerator
pedal
to



code
1000
(short
blink
and
then
light
goes
out
for
long
period)

the
floor
five
times
within
five
seconds
.
TheCheck
Engine



is
present,
then
depress
the
throttle
fully
for
at
least
10
sec-

light
will
then
remain
on
for
five
seconds,
blink
off,
come
on
for



onds
.
Read
the
fault
codes
as
described
earlier
and
check
for
the
1444
code
(no
faults
stored)
.

-,--------------
Check
Engine
light
on

Check
Engine
light
off

Code
1211
:
DM
E
Control
Module



DME
control
module
may
be
faulty
.
This
code
appears
if
the
control
module
fails
the
self
test
.
Check
inputsto
control
module
.
Repair
Group
130

Code
1215
:
Mass
air
flow
sensor



Check
air
flow
or
mass
air
flow
sensor
and
wiring
to
sensor
.
Repair
Group
130

Test
throttle
potentiometer
resistance
and
wiring
.
Repair
Group
130

Test
DME
control
module
input/outputs
.
Repair
Group
130

Test
DME
control
module
input/outputs
.
Repair
Group
130

Check
sensor
output
signal
to
DME
control
module
.
Repair
Group

Code
1222
:
Oxygen
sensor
lean/rich
control
stop



Check
for
intake
air
leaks
or
reasons
forrich
míxture
.
See
Driveabil-
ity
Troubleshooting
given
earlier
in
this
repair
group

Code
1223
:
Coolant
temperaturesensor
(NTC)



1
Test
coolant
temperature
sensor
.
Repair
Group
130

Test
intake
air
temperature
sensor
.
Repair
Group
130

Code
1225
:
Knock
sensor#1
(DME
3
.3
.1
only)



1
Check
knocksensorand
sensor
wiring
.
Repair
Group
120

Check
knocksensor
and
sensor
wiring
.
Repair
Group
120

Code
1231
:
Batteryvoltage
monitor



Test
battery
voltage
and
battery
check
charging
system
and
starter
.
Repair
Group
121

Code
1234
:
Speedometer
"A"signal
(DME
3
.3
.1
only)



Check
wiring
between
instrument
cluster
and
DME
control
module
.
Electrical
Wiring
Diagrams

Code
1237
:
A/C
compressor
cutoff
(DME
3
.3
.1
only)



Test
DME
control
module
inputs/outputs
from
A/C
system
.
Repair
Group
130

Code
1242
:
A/C
compressor
signal
(DME
3
.3.1
only)



Test
DME
control
module
inputs/outputs
from
A/C
system
.
Repair
Group
130

DRIVEABILITY
TROLIBLESHOOTING

100-
1
0
ENGINE-GENERAL

Table
d
.
OBD
I
Fault
(Blink)
Codes
(continued)

(1992-1995
modeis
only)

Graphic
representation
of
flashing
Check
Engine
light
fault
code
:
1221
-
;
5
Seconds
.
;--~
2
.5
r
----------------
Check
Engine
light
on

Fault
code
and
meaning



Corrective
action

Check
Engine
light
off

Code
1243
:
Crankshaft
position
sensor
(DME
3
.3
.1
only)



Test
crankshaft
position/rpm
sensor
and
wiring
from
sensor
lo
DME

control
module
.
Repair
Group
120

Code
1244
:
Camshaft
position
sensor
(DME
3
.3
.1
only)



Test
camshaft
position
sensor
and
wiring
fromsensor
to
DME
con-
trol
module
.
Repair
Group
130

Code
1245
:
Electronic
transmission
control
intervention
(DME
3
.3
.1



Check
wiring
between
DME
control
module
and
auto
.
transmission
only)



control
module

Code
1247
:
Ignition
secondary
monitor
(DME
3
.3
.1
only)



Check
secondary
voltage
lo
ignition
coils
.
Check
wiringat
ignition

coils
.
Repair
Group
120

Code
1251
:
Fuel
injector
#1
(DME
3
.113
.3
.1
only)



1
Test
injector
operation/signal
lo
injector
.
Repair
group130

Code
1252
:
Fuel
injector
#2
(DME
3
.113
.3
.1
only)



Test
injector
operation/signal
lo
injector
.
Repair
group130

Code
1253
:
Fuel
injector
#3
(DME
3
.1/3
.3
.1
only)



Test
injector
operation/signal
to
injector
.
Repair
group130

Code
1254
:
Fuel
injector
#4
(DME
3
.1/3
.3
.1
only)



Test
injector
operation/signal
to
injector
.
Repair
group
130

Code
1255
:
Fuel
injector
#5
(DME
3
.1/3
.3
.1
only)



Test
injector
operation/signal
to
injector
.
Repair
group130

Code
1256
:
Fuel
injector
#6
(DME
3
.1/3
.3
.1
only)



Test
injector
operation/signal
lo
injector
.
Repair
group130

Code
1261
:
Fuel
pump
control



Test
fuel
pump
relay
and
fuel
pump
circuit
.
Repairgroup
160

Code
1262
:
Idle
speed
control



Test
idleair
controlvalve
and
signalto
valve
.
Repair
Group
130

Code
1263
:
Fuel
tank
evaporative
(EVAP)
system



Test
EVAP
purge
valve
.
Repair
Group
160

Code
1264
:
Oxygen
sensor
heater



1
Test
oxygen
sensorheater
and
heater
relay
.
Repair
group
130

Code
1265
:
Check
engine
lamp
(DME
3
.3.1
only)



1
Test
for
faulty
bulb
or
wiring
.
Electrical
Wiring
Diagrams

Code
1266
:
VANOS
(DME
3
.3
.1
only)



1
Test
VANOS
solenoid
.
Check
for
signal
to
VANOS
solenoid
.

Code
1267
:
Air
pump
relay
control
(DME
3
.3
.1
only)



Test
air
pump
relay
and
wiring
(where
applicable)
Electrical
Wiring
Diagrams
Code
1271
:
Ignition
coil
#1
(DME
3
.3.1
only)



Test
ignitioncoil
and
wiring
toignitioncoil
.
Repair
Group
120

Code
1272
:
Ignition
coil
#2
(DME
3
.3.1
only)



Test
ignitioncoil
and
wiring
loignitioncoil
.
Repair
Group
120

Code
1273
:
Ignition
coil
#3
(DME
3
.3.1
only)



Test
ignitioncoil
and
wiring
loignitioncoil
.
Repair
Group
120

Code
1274
:
Ignítion
coil
#4
(DME
3
.3.1
only)



Test
ignitioncoil
and
wiring
toignitioncoil
.
Repair
Group
120

Code
1275
:
Ignitioncoil
#5
(DME
3
.3.1
only)



Test
ignition
coil
and
wiring
loignitioncoil
.
Repair
Group
120

Code
1276
:
Ignition
coil
#6
(DME
3
.3.1
only)



Test
ignitioncoil
and
wiring
loignitioncoil
.
Repair
Group
120

Code
1281
:
DME
control
module
memory
supply
(DME
3
.3
.1
only)



Check
voltage
supply
from
battery
lo
DME
control
module
.
Electri-

Code
1282
:
Fault
code
memory
(DME
3
.3.1
only)



Check
DME
control
module
inputs/outputs
.
Control
module
may
be
faulty
.
Repair
Group
130

Code
1283
:
Fuel
injector
output
stage
(DME
3
.3
.1
only)



Check
DME
control
module
inputs/outputs
.
Control
module
may
be
faulty
.
Repair
Group
130

DRIVEABILITY
TROUBLESHOOTING

cal
Wiring
Diagrams

Graphic
representation
of
flashing
Check
Engine
light
fault
code
:
1221

-
;
5
Seconds
.
~-



2
.5;-

Fault
code
and
meaning



Corrective
action

Code
1286
:
Knock
control
test
pulse
(DME
3
.3
.1
only)



Check
DME
control
module
inputs/outputs
.
Control
module
may
be
faulty
Repair
Group
130

Code
1000
(light
remains
off)
:



End
of
fault
code
output-all
fault
codes
have
been
displayed
.
No

~
corrective
action
necessary
.
Repeat
test
if
necessary

Code
1444
:



No
more
faults
.
No
corrective
action
necessary
.
This
code
must
be
present
lo
erase
fault
memory

Basic
Requirements



Preventive
Maintenance

The
following
list
contains
basic
checks
that
should
be
made
when
experiencing
driveability
problems
.

1
.
Check
intake
(induction)
system
for
leaks
.
Check
for

cracked,
loose,
or
disconnected
hoses
and
duct
work
.

Check
that
all
hose
clamps
are
tight
.

NOTE-

An
air
leak
allows
unmeasured
airto
enter
the
engine,
offen
resulting
in
an
in
overly
lean
fuel
mixture
and
causing
driveability
problems
which
will
cause
the
Check
Engine
light
to
come
on
.

Table
d
.
OBD
I
Fault
(Blink)
Codes
(continued)

(1992-1995
models
only)

7
-
1
--------------
Check
Engine
light
on

ENGINE-GENERAL
100-
1
1

Check
Engine
light
off

The
condition
of
the
fuel,
ignition
and
emission
controlsys-

tem
components
has
a
directeffect
onengineperformance

and
driveability
.
BMW
specifies
maintenance
of
certain
parts

at
regular
intervals
lo
keep
the
engine
in
proper
tune
.
Extend-
ing
maintenance
intervals
beyond
the
time
or
mileagerecom-
mended
bythe
manufacturer
can
adversely
affect
the
way
the
engine
runs
.
When
troubleshooting
driveability
problems,
a
good
starting
point
is
to
perform
a
major
engine
service,par-

ticularly
if
one
is
overdue
.
For
maintenance
schedules,
major
engine
service
and
other
driveability-related
maintenance

procedures,
see020
Maintenance
Program
.

Basic
Engine
Settings

2
.
Check
that
the
battery
isin
good
condition
.
Check
that

the
cables
are
tight
and
free
of
corrosion
at
both
ends
.



Idle
speed,
idle
mixture
(%CO),
and
ignition
timing
are
not

Check
that
all
related
ground
points
are
firmly
connect-



adjustable
.
The
adaptive
engine
management
system
is
de-

ed
and
in
good
condition
.
Check
al¡
harness
connectors



signed
lo
automatically
compensate
for
changes
in
engine
op-

for
damage
and
corrosion
.



erating
conditions,
although
the
adaptive
range
is
limited
.

Once
these
limits
are
exceeded,
driveability
problems
usually

3
.
Check
for
prwer
and
ground
at
the
Engine
Control



become
noticeable
.

Module
(ECM)
.
Check
the
main
grounds
for
the
ECM
.

See130
Fuel
Injection
.



NOTE-

If
the
DME
adaptive
limits
are
exceeded,
the
Check
En-
4
.
Check
the
fuses
.
Check
for
sufficient
fuel
in
the
tank
.
If



gine
light
will
come
on,
indicating
an
emission
related
the
engine
ranout
of
fuel,
it
will
take
a
little
time
to
re-



fault
.
See
130
Fuel
Injection,
store
fuel
pressure
.
See
160
Fuel
Tank
and
Fuel

Pump
.
Oxygen
Sensors

5
.
Check
for
spark
at
the
spark
plugs
.
If
the
tachometer

needle
bounces
while
the
engine
is
crankedby
the



A
high
oxygen
level
in
the
engine
exhaust
indicates
a
lean

starter
then
the
ignition
system
is
probably
working
cor-



air-fuel
mixture
and
a
low
oxygen
level
indicates
a
rich
mix

rectly
.
See
120
Ignition
System
.



ture
.
The
oxygen
sensor,
shown
in
Fig
.
10,
measures
the
oxy-

gen
content
in
the
exhaust
gasand
generates
a
variable

6
.
Check
for
any
faults
through
the
On-Board
Diagnostics



voltage
signal
.
Using
that
feedback
signal
asan
input,
the

system
.
See
On-Board
Diagnostics
(OBD)
.



DME
control
module
fine
tunes
the
air-fuel
mixture
.

DRIVEABILITY
TROUBLESHOOTING

100-
1
2
ENGINE-GENERAL

NOTE-

The
oxygen
sensor
signal
is
ignored
until
the
engine
reachesa
specified
minimum
temperature
.
Therefore,



The
primary
input
usedby
the
fuel
injection
system
to
deter-

when
troubleshooting
cold
engine
driveability
prob-



mine
how
much
fuel
should
be
delivered
is
the
signal
from
the

lems,
the
oxygensensor
canbe
ruled
out
asa
possible



mass
air
flow
sensor
in
the
intake
air
ductwork
.

cause
.

As
the
oxygen
sensor
ages,
its
ability
to
react
quickly
to

changing
conditions
deteriorates,
and
it
may
eventually
cease

to
produce
any
signal
at
all
.
To
check
the
operation
of
the
oxy-

gen
sensor,
see
130
Fuel
Injection
:

NOTE-

On
1996
and
latercars,
OBD
11
enhanced
emission
standards
require
the
engine
control
module
(ECM)
to
monitor
the
oxygen
content
in
the
exhaust
both
before
and
after
the
catalytic
converter
.
Thisallows
for
tighter
control
of
the
tail
pipe
emissions
and
also
allowsthe
ECM
to
diagnose
converter
problems
.
If
the
DME
de-
tects
that
catalytic
converter
or
oxygensensor
efficien-
cyhas
degraded
pasta
certain
pre-programmed
limit,
it
will
turn
on
the
Check
Engine
light,
and
store
a
diag-
nostic
trouble
code
(DTC)
in
the
ECM
.

DRIVEABILITY
TROUBLESHOOTING

Catalytic

B9506

Air
Flow
Measurement
and
Vacuum
Leaks

Because
proper
fuel
metering
depends
on
accurate
mea-

surement
of
the
incoming
air,
any
unmeasured
air
that
enters

the
engine
downstream
of
the
mass
air
flow
sensor
will
cause

a
lean
air-fuel
mixture
and
possibly
affectdriveability
.

NOTE-

Fig
.
10
.
Regulating
oxygen
sensor
measures
oxygen
content
of
ex-



gattery
Voltage
hausY
gas
as
indicator
of
.¡_fi
.1
ratio
and
"-k,
.

E-
effi-
ciency
.
Monitoríng
oxygen
sensor
(not
shown)
monitors

If
a
large
air
leak
is
causing
driveability
problems,
the
Check
Engine
light
will
usually
be
illuminated
and
a
fault
will
be
stored
in
the
fault
code
memory
.
See
On
Board
Diagnostics
(OBD)
.

There
are
many
places
for
unmeasured
air
to
enter
theen-

gine
.
First,
inspect
all
hoses,
fittings,
ducts,
seals,
and
gaskets

in
the
intake
air
tract
for
cracks
or
looseness
.
It
may
be
neces-

sary
to
remove
parts
that
cannot
be
fully
checked
in
their
in-

stalled
positions
.
Also
make
sure
all
of
the
intake
manifold
and

throttle
body
mounting
nuts
are
tight
.

In
addition
to
air
leaks,
air
restrictions
can
also
cause
drive-

ability
problems
.
Remove
the
air
filter
and
hold
it
up
to
a
strong

light
source
.
If
the
filter
does
not
pass
light,
it
is
restricted
and

should
be
replaced
.
Also,
remove
the
intake
air
ductwork
and

check
for
oily
deposits
at
the
throttle
plate
.
Buildup
in
this
area

can
cause
an
erratic
idle
.
Clean
away
any
deposits
using
a

cloth
wetted
withcarburetor
cleaner
and
reinstall
the
ductwork
.

CAUTION-

Do
not
spray
carburetor
cleaner
directly
in
the
throt-
tle
anea
.
Spraying
cleaner
may
force
it
into
the
throt-
tle
position
switch
or
sensor
and
cause
damage
.

catalytic
converter
operation
.



All
of
the
electrical
components
in
the
fuelinjection
and
igni-
tion
systems
require
a
minimum
voltage
to
operate
properly
.

When
troubleshooting
engine
driveability
problems,
one
of
Replacement
of
oxygensensors
at
the
specified
intenrals
en-



the
first
checks
should
be
to
make
sure
the
battery
is
fully
sures
that
the
engine
and
emission
control
system
wili
continue



charged
and
capable
of
delivering
allits
power
to
the
electricalto
operate
as
designed
.
As
the
oxygen
sensor
ages,
its
ability
to



system
.
react
quickly
to
changing
conditions
deteriorates,
and
it
may
eventually
cease
to
produceany
signal
at
all
.



To
make
a
quick
check
of
battery
charge,
measure
the
volt-
age
across
the
battery
terminals
with
all
cables
attached
and
As
the
oxygen
sensor
ages,
its
ability
to
react
quickly
to



the
ignition
off
.
A
fully
charged
battery
will
measure
12
.6
volts
changing
conditions
deteriorates,
and
it
may
eventually
cease



or
slightly
more,
compared
to
12
.15
volts
for
a
battery
with
a
to
produce
any
signal
at
all
.
To
check
theoperation
of
the
oxy-



25%
charge
.
gen
sensor,
see130
Fuel
Injection
.

Even
a
fully
charged
battery
cannot
deliver
power
unless
it

is
properly
connected
to
the
electrical
system
.
Check
the
bat-
tery
terminals
for
corrosion
and
loosecableconnections
.
If
the
battery
does
not
maintain
the
proper
voltage,
the
charging
system
may
be
atfault
.
See
121
Battery,
Starter,
Alternator
.

If
a
battery
cableconnection
hasno
visible
faults,
but
is
still
suspect,
measure
the
voltage
drop
across
the
connection
.
A
large
drop
indicates
excessive
resistance,
meaning
the
con-
nection
is
corroded,
dirty,
or
damaged
.
Clean
or
repair
the
connection
and
retest
.

NOTE-

For
instructions
on
conducting
a
voltage
drop
test,
and
other
general
electrical
troubleshooting
information,
see600
Electrical
System-General
.

Wiring
and
Harness
Connections

The
electronic
fuel
injection
and
ignition
systems
operate
at

low
voltage
and
current
values,
making
them
sensitive
to

small
increases
in
resistance
.
The
electrical
system
is
routine-

ly
subjected
to
corrosion,
vibration
and
wear,
so
faults
or
cor-

rosion
in
the
wiring
harness
and
connectors
are
common
causes
of
driveability
problems
.

Visually
inspect
all
wiring,
connectors,
switches
and
fuses
in
the
system
.
Loose
or
damaged
connectors
can
cause
inter-

mittent
problems,
especially
the
smallterminals
in
the
ECM

connectors
.
Disconnect
the
wiring
harness
connectors
to

check
for
corrosion
;
and
use
electrical
cleaning
spray
to
re-

move
contaminants
.
Often,
simply
disconnecting
and
recon-

necting
a
dirty
connector
several
times
will
clean
the
terminals
and
help
to
reestablish
good
electrical
contact
.

If
a
wiring
harnessconnectorhasno
visible
faults,
but
is
still

suspect,
measure
the
voltage
drop
across
the
connector
.
A

large
drop
indicates
excessive
resistance,
meaning
the
con-

nector
is
corroded,
dirty
or
damaged
.
Clean
or
repair
the
con-

nector
and
retest
.

Ground
Connections

For
any
electrical
circuit
to
work,
it
must
make
acomplete

path,
beginning
at
the
positive
(+)
battery
terminal
and
ending

at
the
negative
(-)
terminal
.
The
negative
(-)
battery
cable
is

attached
to
the
car's
chassis
.
Therefore,
any
wireor
metal

part
attached
to
the
chassis
provides
a
good
ground
path
back

to
the
negative
(-)
battery
terminal
.

Poorground
connections
are
amajor
source
of
driveabílity

problems
.
If
any
of
themainground
connections
for
the
igni-
tion
system
or
the
fuelinjection
system
are
faulty,
the
in-

creased
resistance
in
that
circuit
will
cause
problems
.

Visually
inspect
al¡
ground
wires
and
connections
for

breaks,
looseness
or
corrosion
.
Be
careful
because
wires

sometimes
break
internally
or
in
areas
not
easily
visible
.
The

main
grounds
for
the
DME
system
are
shown
in
Fig
.
11,Fig
.

12,
and
Fig
.
13
.
Also
check
the
main
fuel
pump
ground
in
the
center
console,
below
the
emergency
brake
handle
.

If
a
ground
connection
has
no
visiblefaults,
but
is
still
suspect,

measure
the
voltage
drop
acrossthe
connection
.
A
large
drop

indicates
high
resistance,
meaning
the
connection
is
corroded,

dirty
or
damaged
.
Clean
or
repair
the
connection
and
retest
.

ENGINE-GENERAL
100-
1
3

UU,~uyi

Fig
.
11
.
Mainground
(arrow)
for
engine
management
system
.
Grounds
are
in
right
rear
of
engine
compartment
.

Fig
.
12
.
Mainground
for
ignition
coils
on
MS
41
.1
engine
manage-
ment
system
(arrow)
.

DRIVEABILITY
TROLIBLESHOOTING

al
Icld

Table
e
.
Engine
Driveability
Troubleshooting

c
l



1



I



f



I



I
Oxygen
sensor
faulty



Test
oxygen
sensor
.

ENGINE-GENERAL
100-
1
5

SYMPTOMS

a
.
Engine
fafs
tostart

b
.
Engine
startsbut
stops
immediately

c
.
Erratic
engine
idle

d
.
Poor
engine
responseon
acceleration

e
.
Erratic
engine
operation
in
al¡
speed
ranges

f
.
Excessive
fuel
consumption
g
.
Poor
enginepower,
fails
to
rev
up
h
.
CO
content
toolow

i.
CO
content
too
high

CAUSES



CORRECTIVE
ACTION

a



Fuel
pump
faulty



Test
fuel
pump
.
Repair
Group
160

a



e



Ignition
system
faulty



Test
ignition
system
.
Repair
Group
120
a



Main
relay
or
fuel
pump
relay
faulty



Test
main
relay
.
Repair
Group
130
a



Crankshaft/rpm
position
sensor
faulty



Test
crankshaft/rpm
sensor
.
120
b



c



h



i



ldle
speed
control
valve
faulty



Test
idle
speed
control
valve
.

c



d



e



Throttle
position
sensor
faulty
or
idle
signal
to



Test
throttle
position
sensor
.
DME
control
module
missing
.

c



d



h



i



Mass
air
flow
sensor
faulty



Test
mass
air
flow
sensor
Repair
Group
130
a



b



c



d



e



h



Large
air
intake
system
leak



Check
for
major
intake
air
leaks
downstream
of
mass
air
flow
sensor
.

a



c



d



e



g



h



Fuel
pressure
too
low



Test
fuel
pressure
.
Repair
Group
130

?



I



F
ue
l
pr
essu
r
e
t
oo
high



T
est
f
u
el
pressure
.
Repair
Group
130
d



e



g



h



Fuel
pump
delivery
volume
too
low



Test
fuel
pump
delivery
volume
.
Repair
Group
160
a



c



e



f



h
q
C
oo
l
a
nt
t
e
mp
e
r
a
t
u
r
e
se
n
so
r
f
au
lty



--]
T
est
coo
l
a
n
t
temp
erature
sensor
.

c



e



~



f



i



~
Fuel
injectors
leaking



Check
fuel
injectors
and
replace
leaking
injectors
.

~
Repair
Group
130

Throttle
plate
binding
or
incorrectly
adjusted



Check
throttle
plate
and
adjust
if
necessary
.

a



c



Electrical
connections
loose,
broken,
or
cor-



Visually
inspect
connectors
and
correct
any
roded



faults
.
Repair
Group
600
Ground
connections
loose,
broken,
or
corroded



Visually
inspect
ground
connections
and
correct
any
faults
.
Repair
Group
600

c



e
~



f



CO
content
too
high



Test
air
flowor
mass
air
flow
sensor
.
Repair

~
Group
130
a



b



c



d



e



CO
content
too
low



Test
mass
air
flow
sensor
.
gb



c



d



e



f



g



h



i



Inputsignals
to
ECM
missing,
ECM
in
limp



Make
electrical
tests
at
DMEECM
relay
.
Repair

home
mode



Group
130
a
~
b
~
c
~
d



e]



f



g



h



i



ECM
faulty



Test
DMEECM
inputs
.
If
all
inputs
are
correct,
replace
ECM
.

DRIVEABILITY
TROUBLESHOOTING