1994 BMW M3 speed sensor

020
Maintenance
Program

GENERAL
.
.
...
.
.
.
...
.
.
.
.
.
.
.
.
.
.
.
...
.
..
020-2

BMW
Service
Indicator
......
..
....
..
...
..
.
020-2

Oil
Service
.....
.
..........
..
...
...
...
..
.
020-2

Inspection
I
and
Inspection
II
.
..
....
..
...
..
.
020-2

Resetting
Service
Indicator
....
.
....
..
...
..
.
020-3

MAINTENANCE
TABLES
..
.
.
.
.
.
........
020-3

FLUID
AND
LUBRICANT

SPECIFICATIONS
.
.
.
.
.
.
.
...
.
.
.
....
.
...
020-8

Manual
Transmission
Fluid
..
.
.
.
.
.
....
.
.
.
.
020-8

Automatic
Transmission
Fluid
.
.
.
.
.
....
.
.
.
.
020-8

Final
Drive
Gear
Oil
................
.
.
.
.
020-9
Brake
Fluid
.
.
.
.
.
................
.
.
.
.
020-9
Engine
Coolant
(Anti-freeze)
.
.
...
.
....
.
.
.
.
020-9

Power
Steering
Fluid
........
..
......
.
.
.
.
020-9

ENGINE
OIL
SERVICE
.
.
...
.
.
.
...
.
.
.
.
.
.
020-9

Engine
oil,
checking
leve¡
..
...
...
..
........
020-9
Engine
oil
and
filter,
changing
....
.
......
.
..
020-9

ENGINE
COMPARTMENT

MAINTENANCE
...
.
.
.
.
.
.
.
.
.
.
.
.
.
......
020-10

Air
filter,
replacing
.
...
...
.
.....
.
.....
.
...
020-11

Spark
plugs,
replacing
...
.
......
.
...
..
...
020-11

¡dle
Speed
.
..
...
...
....
.
......
.
...
..
...
020-12

Battery,
checking
and
cleaning
.......
..
...
020-12

Battery,
replacing
.
.....
.
.....
.
.....
..
...
020-12

Accelerator
and
Throttle
Linkage
.
.....
..
...
020-13

Engine
DriveBelts
.....
.
....
..
...
...
...
.
020-13

V-belt,
replacing

(4-cylinder
engines
built
up
to
1/94)
..
....
.
020-13

Poly-ribbed
belt,
replacing

(4-cylinder
engines
built
from
1194

and
all
6-cylinder
engines)
.
.
....
..
......
020-13

Cooling
System
Service
.
...
..
....
..
....
..
020-14

Power
steering
fluid,
checking
leve¡
.
..
....
.
.
020-14

Oxygen
Sensors
....
...
..
..
....



.
.....
.
.
020-15

MAINTENANCE
PROGRAM



020-1

UNDER-CAR
MAINTENANCE
.
..
.
...
.
.
.020-16
'

Fuel
filter,
replacing
...
.
.....
..
.....
..
..
.020-16

Tires,
checking
inflation
pressure
.
.....
.
....
020-17

Tires,
rotating
...
..
.....
..
....
..
....
.
....
020-17

Wheels,
aligning
..
.....
.
...........
.
....
'020-17

Brake
system,
inspecting
.
.
....
.
.....
..
...
020-17

Brake
pad/rotor
wear,checking
.
......
.
....
020-17

Brake
fluid,
replacing
.........
..
.



..
..



.
020-17

Parking
brake,
checking
......
.
.....
..
....
020-17

Exhaust
system,
inspecting
....
..
.....
.
...
.020-18

Manual
Transmission
Senrice
..
..
.....
.
....
020-18

Manual
transmission
fluida

checking
and
filling
..
.
....
..



.
.
..
..
....
020-18

AutomaticTransmission
Service
.
....
...
....
020-18

Front
suspension
and
steeringlinkages,
inspecting
..
.
:.....
.
....
..
.....
..
...
.
.020-18

Rear
suspension,
inspecting
.
..
...
...
....
..
020-18

Final
drive
oil
leve¡,
checking
.
.
.
...
....
...
..
020-18

Fuel
tank
and
fuel
lines,
inspecting
.
.....
....
020-19

Clutch
fluid,
checking
...
...
...
...
....
.....
020-19

Drive
axle
joint
boots,
inspecting
...
..
.....
..
020-19

BODY
AND
INTERIOR

MAINTENANCE
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
...
.
.020-19
Windshield
Wiper
Blade
Maintenance
....
.
.
020-19

Body
and
hinges,
lubricating
.
.....
..
......
.
020-19

Seat
Belts
...
..
...
...
...
..
.....
..
.....
.
.
020-20

Exterior
Washing
..
...
...
..
.
.
...
..
......
.020-20

Waxing
.....
..
...
...
...
..
.....
..
.......
020-20

Polishing
..
...
...
...
....
..
..........
..
.
.'020-20

Washing
Chassis
.
...
....
.
....
..
.....
.
...
020-20

Special
Cleaning
.
.
.....
..



...
.
.....
..
..
.020-20

Interior
Care
.
....
..
....
..
..



.
.
......
.
...
020-20

Leather
Upholstery
and
Trim
...
..
....
...
...
020-20

TABLES

a
.
Oil
Service
......
...
.
..
.............
...
---
020-4

b
.
Inspection
1
Service
..
.
.
.............
....
...
020-5

c
.
Inspection
11
Service
.
.
...
...........
..
.
..
..
020-6

d
.
Scheduled
Maintenance-Time/Mileage
Intervals
..
020-7

e
.
Fluids
and
Lubricants
..
...
...........
.....
..
020-8

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

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

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

Camshaft
timing
chains,
removing

(6-cylinder
engines)

1
.
Disconnect
negative
(-)
cable
from
battery
.

CA
UTION-

Disconnecting
the
battery
may
erase
fault
codes)
stored
in
control
module
memory
.
Check
for
fault
codes
using
special
BMW
diagnostic
equipment
.

2
.
Drain
engine
coolant
.
Drain
engine
block
by
removing

block
drain
.
Remove
radiator
cooling
fan
shroud
and

cooling
fan
.
See170
Radiator
and
Cooling
System
.
.

WARNING
-

Allow
the
engine
to
cool
before
openingor
draining
the
system
.

CAUTION-

Radiator
fan
has
left
hand
threads
.

NOTE-

The
block
drain
plug
is
located
on
the
exhaust
side
of
the
engine,
below
cylinder
no
.
4
.

3
.
Drain
engine
oíl
andremove
oil
pan
.
See
119
Lubrica-

tion
System
.

4
.
Remove
alternator
cooling
duct
.

5
.
Remove
two
large
coolant
hoses
from
thermostat

housing
.
Remove
engine
lifting
bracket
and
thermostat

housing
from
front
of
cylinder
head
.

6
.
Loosen
bolts
for
coolant
pump
pulley
.
Then
remove

drive
belts
for
alternator
andA/C
compressor
.
See
020

Maintenance
Program
.
Remove
coolant
pump
pulley
.

Fig
.
16
.

NOTE-

OnM50
engines
with
a
two-roller
drive
belt
tensioner,

remove
the
upper
rollerto
access
thetensioner
mount-
ing
bolts
.

NOTE-

Make
note
of
the
arrangement
of
the
rubber
insulators

when
removing
the
cylinder
head
cover
mounting
bolts
.

CAMSHAFT
TIMING
CHAIN



117-
7

Fig
.
16
.
Drive
belt
tensioner
mounting
bolts
(arrows)
.

B11055

7
.
Remove
drive
belt
tensioner
from
front
of
engine
.
See



Fig
.
17
.
1992-1995
M50
engine
speed
sensor
on
timing
cover
(ar-
row)
.

10
.
Unclip
andremove
baffle
cover
from
above
intake
cam-

shaft
.
See
Fig
.
18
.

11
.
On
1992
engines
:
Remove
upper
timing
chain
cover

from
front
of
cylinder
head
.
See
Fig
.
19
.

8
.
Remove
engine
speed
sensor
from
lower
timing
chain



12
.
Loosen
spark
plugs
.
See
120
Ignition
System
.

cover,
if
applicable
.
See
Fig
.
17
.

13
.
Set
engine
to
approximate
TDC
by
rotating
in
normal

9
.
Remove
cylinder
head
cover
.
See
113
Cylinder
Head



operating
direction
until
camshaft
lobes
at
cylinder
no
.

Removal
and
Installatíon
.



1
are
facing
each
other
.
See
Fig
.
20
.

14
.
Set
engine
to
TDC
by
aligning
"0/T'
mark
(0°TDC)on

front
vibration
damper
with
cast
bosson
lower
timing

chain
cover
.
See
Fig
.
21
.

15
.
Remove
vibration
damper
mounting
bolts
and
remove

vibration
damper
and
pulley
.
See
Fig
.
22
.

CAMSHAFT
TIMING
CHAINS,
6-CYLINDER