1994 BMW M3 Workshop Manual

001ía4
i

Fig
.
34
.
Intake
air
temperature
(IAT)
sensor
in
top
section
of
air
filter
housing
.

¡die
speed
control
valve,
replacing

side
of
the
throttle
body
.
See
Fig
.
35
.

1
.
Disconnect
harness
connector
from
¡die
valve
.

0012725

Fig
.
35
.
M44
engine
:
Throttle
housing
showing
(A)
throttle
position
sensor
(fPS)
and
(B)
¡die
speed
control
valve
.

2
.
Remove
twomountingscrews
holding
sensor
to
throttle

housing
.

The
¡die
speed
valve
on
the
M44
engine
is
located
on
the

FUEL
INJECTION



130-23

2
.
Disconnect
vacuum
hose
and
retaining
screws
.

3
.
Pull
¡die
speed
control
valve
from
its
fittings
.

4
.
Installation
is
reverse
of
rémoval
.
Always
replace
0-

rings
and
seals
.

NOTE

Poor
driveability
may
be
notíced
after
installing
a
re-
placement
¡dio
control
valve
.
After
about10
minutes
of
driving,
the
idie
speed
should
retum
to
normal
.

SIEMENS
MS
41
.1

COMPONENT
REPLACEMENT

On-Board
Diagnostics
II
(OBD
II)
is
incorporated
into
the
Si-

emens
MS
41
.1
engine
management
systems
used
in
the

M52
and
S52US
engine
.
Refer
to
Fig
.
36
.

OBD
11
is
capable
of
detecting
a
fui¡
range
offaults
.
When

faults
are
detected,
a
Diagnostic
Trouble
Code
(DTC)
is

stored
in
the
system
ECM
.
The
Check
Engine
warning
light
will
also
come
on
if
an
emissions-related
fault
is
detected
.
The

most
efficient
way
to
diagnose
the
Siemens
OBD
II
system
is

by
using
a
specialized
scan
tool
.
The
OBD
II
system
is
capa-

ble
of
storing
hundreds
of
faults,
making
diagnostics
with
a
scan
tool
the
only
viable
method
.
Therefore,
system
diagnos-

tics
is
not
covered
here
.

NOTE
-

"
The
OBD
11
fault
memory
(including
an
illuminated

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
.

"
The
16-pin
OBD
11
diagnostic
connector
is
located
on

the
lower
left
dash
panel
.
Refer
to
Fig
.
1
.

"
BMW
special
scan
tool
ora
"generic"
OBD
11scan
tool

must
be
used
to
access
DTCs
.
3
.
Installation
is
reverse
of
removal
.
No
adjustment
is
nec
essary
.



"
Table
1
lists
engine
control
module
(ECM)
pinouts
forthe
MS
41
.1
systems
.

SIEMENS
MS
41
.
1
COMPONENT
REPLACEMENT

130-24



FUEL
INJECTION

Jo
'0

o_A

í1
RELAY

..
.
.

CAMSHAFT
POSITION
SENSOR

'
.
~'



~
:UhI~IIUH~W~`bY~7~d~t~II7

.
.
.
,

1111111
~ilf

ASC

TERMINAL
15

MEMORY
POWER

CRANKSHAFT
POSITION
qtcMSENSOR

THROTTLE
POSITION

ENGINE
COOLANT
TEMP

FUELTANK
PRESSURE
SENSOR

S-EML
S-MSR

S-ASC

VEHICLE
SPEED

LOW
FUEL
LEVEL

A/C
SWITCH
ON
(AC)
E36
IHKA



COMPRESSOR
"ON"
SIGNAL
(KO)

INDIVIDUAL
SERIAL
NUMBER

SIEMENS
MS
41
.
1
COMPONENT
REPLACEMENT

FUEL
PUMP
RELAY
CONTROL
AUX
GROUND
P

MAIN
GROUND
AC
COMPRESSOR
RELAY
CONTROL



~®

SECONDARY
AIR
INJECTION
AIR
PUMP
RELAY
CONTROL
-
M

PRE
CAT



POST
CAT
m
nXYGEN
SENSOR

ys
U
~
4



,
HEATING

FUELINJECTOR
CONTROL
(

MS
41
.1



(

MS

PURGE
CONTROL
VALVE



//



PURGE
'
CANISTERSHUT-OFF
VALVE

ECM
RELAY
CONTROL

IGNITION
COILS
CONTROL

1
ASC

o
ayi

THROTTLE
POTENTIOMETER
POWER

,

al
;
..
i

r71a
.

"a
fn7111,
/



r

Fig
.
36
.
Siemens
MS
41
.1
OBD
II
engine
management
system
usedon
M52
engine
.
Bosch
M5
.2
systemusedon
M44
engine
is
similar
.

Mass
air
flow
sensor,
replacing

1
.
Disconnect
harness
connector
and
intake
air
boots

from
air
flow
sensor
.
See
Fig
.
37
.

Fig
.
37
.
Mass
air
flow
sensor
(arrow)
on
M52
engine
.

2
.
Installation
is
reverse
of
removal
.

"
No
adjustment
to
aír
flow
sensor
is
possible
.

"
Check
intake
hoses
for
cracks
and
vacuum
leaks
.

Engine
coolant
temperature(ECT)
sensor,

replacing

The
ECT
sensor
is
a
dual
temperature
sensor
.
One
circuit

provides
coolant
temperature
information
to
the
ECM
while

the
other
circuit
provides
coolant
temperature
information
to

the
instrument
cluster
.

1
.
Remove
left-side
top
engine
cover
.

4
.
Remove
sensor
.

5
.
Installation
is
reverse
of
removal
.

"
Replace
any
lost
coolant
.

0012703

"
Use
a
new
copper
sealing
washer
when
installing
new

Tightening
Torque

"
Engine
coolant
temperature

to
cylinder
head
.....
..
.
...
......
13
Nm
(10
ft-Ib)

FUEL
INJECTION



130-
25

0012704b

Fig
.
38
.
M52
engine
:
Engine
coolant
temperature
(ECT)
sensor
(A)
is
located
beneath
top
engine
cover
(8)
and
crankcase
vent

hose
(C)
.

Intake
air
temperature
(IAT)
sensor,

replacing

The
intake
air
temperature
(IAT)
sensor
for
the
M52/S52US

engine
is
mounted
on
the
bottom
of
the
intake
manifold
.
See
Fig
.

39
.

2
.
Unclip
crankcase
venting
hose
from
cylinder
head
cov-

er
.
See
Fig
.
38
.



Fig
.
39
.
M52/S52US
engine
:
Intake
air
temperaturesensor
location
in

bottom
of
intake
manifold(arrow)
.
Throttle
housing
shown
re

3
.
Under
intake
manifold,
disconnect
harness
connector



moved
.

fromsensor
.

1
.
Disconnect
intake
air
bootfrom
throttle
housing
.
Unbolt

throttle
housing
and
¡ay
aside
.
(It
is
not
necessary
to

disconnect
throttle
cable
or
electrical
harnessconnec-

tors
from
throttle
housing
.)

sensor
.



2
.
Remove
electrical
harness
connector
from
IAT
sensor
.

3
.
Unclip
temperature
sensor
and
remove
from
intake

manifold
.

4
.
Installation
is
reverse
of
removal
.
Use
a
new
gasket
at

the
throttle
housing
.

SIEMENS
MS
41
.1
COMPONENT
REPLACEMENT

130-26



FUEL
INJECTION

Throttle
position
sensor
(TPS),
replacing

The
throttie
position
sensor
is
located
on
the
side
of
the
throttie
housing
.
See
Fig
.
40
.

Fig
.
40
.
M52
engine
:
Throttle
position
sensor
(arrow)
.

1
.
Unplug
harness
connector
from
sensor
.

NOTE
-

On
cars
with
tractioncontrol,
do
not
confuse
the
throttieposition
sensor
on
the
main
throttie
body
wíth
the
throt-
tie
position
switch
on
the
secondary
throttie
body,
where
applicable
.

3
.
Installation
is
reverse
of
removal
.

¡die
speed
control
valve,
replacing

0012700b

The
¡die
speed
control
valve
is
mounted
on
the
underside
of
the
intake
manifoldadjacent
to
the
dipstick
tube
bracket
.
Ac-
cessing
the
valve
is
best
accomplished
by
first
removing
the
throttie
housing
.

1
.
Disconnect
intake
air
bootfrom
throttie
housing
.
Unbolt
throttie
body
and
¡ay
aside
.
(Do
not
disconnect
throttie
cable
or
electrical
harness
connectors
to
throttie
body
.)

2
.
Unbolt
dipstick
tube
bracket
from
intakemanifold
.

3
.
Workíng
under
intake
manifold,
disconnect
electrical
harness
connector
from
¡die
speed
control
valve
.

4
.
Remove
two
bolts
retaining
¡die
speed
control
valve
to
underside
of
intake
manifold
.
Remove
valve
from
intake
manifold
.
Remove
hose
clamp
and
disconnect
hose
.

ECM
PIN
ASSIGNMENTS

mately
one
minute
.

Vacuum
seal

Mounting
bracket

Electrical
connector

0013185

Fig
.
41
.
M52
engine
:
¡die
speed
control
valve
(located
under
intake
manifold)
.

5
.
Installation
ís
reverse
of
removal
.
Use
new
gaskets
when
installing
.

NOTE
-

Poor
driveabilíty
may
be
noticed
atter
installing
a
re-
placement
idle
speed
control
valve
.
After
about
10
min-utes
of
dríving
the
idle
speed
should
return
to
normal
.

ECM
PIN
ASSIGNMENTS

2
.
Remove
twomountingscrews
holding
sensor
to
throttie
housing
.



Engine
control
module
(ECM),
accessing

1
.
Disconnect
negative
(-)
battery
cable
.
Wait
approxi-

CAUTION-

Prior
to
disconnecting
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this
manual
onpage
vüi
.

2
.
Remove
engine
control
module
(ECM)
compartment
cover
from
right
side
of
engine
compartment
rear
bulk-
head
.
Cover
is
retained
withfour
captíve
screws
.
See
Fig
.
42
.

3
.
Disconnect
control
module
harness
connector
by
re-
leasing
fastener
and
pivoting
connectorup
and
off
ECM
.

4
.
Remove
ECM
from
retaining
brackets
and
pull
ECM
from
its
holder
.

5
.
Installation
is
reverse
of
removal
.

0013ZIM
Fig
.
42
.
Engine
control
module
(ECM)
located
in
compartment
in
right-rearof
engine
compartment
(arrow)
.

NOTE-

Replacement
ECMs
must
be
coded
with
application
in-
formation
(Le
.
engine
code,
transmission
type,
etc
.)
pri-
or
to
installation
.
Consult
an
authorized
BMW
dealer
before
replacing
the
ECM
.

ECM
pin
assignments
are
given
in
Tables
h
through
Table
I.
This
information
can
be
helpful
when
diagnosing
faultsto
or
from
the
ECM
.
If
al¡
inputs
and
wiring
are
OK
butoperational
problems
still
exist,
the
ECM
itself
may
be
faulty
.

Fig
.
43
.
ECM
pin
numbers
as
seen
from
back
of
ECM
connector
.

FUEL
INJECTION



130-
2
7

Generally,
absence
of
voltage
or
continuity
means
there
is
a
wiring
or
connector
problem
.
Test
results
with
incorrect
values
do
notnecessarily
mean
that
a
component
is
faulty
:
Check
for
loose,
broken
or
corroded
connections
and
wiring
before
re-
placing
components
.
If
the
results
are
still
incorrect,
test
the
component
itself
.
For
engine
management
system
electrical
schematics,
see
Electrical
Wiring
Diagrams
.

CAUTION-

Always
waitat
least
40
seconds
after
tuniing
off
the
ignition
before
removing
the
connector
from
the
engine
control
module
(ECM)
.
If
the
connec-
tor
is
removed
before
this
time,
residual
power
in
the
system
relay
may
damage
the
ECM
.

"
Always
connector
disconnect
the
control
module
connector
and
meter
probes
with
the
ignitionoff
.

When
making
checks
at
the
ECM
itself,
a
breakout
box
should
be
used
to
allow
tests
to
be
made
with
the
connector
attached
to
the
ECM
.
This
also
prevents
damage
tothe
small
termínals
in
the
connector
.
As
an
alternative,
theharness
con-
nector
housing
can
be
separated
so
that
electrical
checks
can
be
made
from
the
back
of
the
connector
.
ECM
pin
numbering
is
shown
in
Fig
.
43
.

NOTE
-

On
cars
with
tractioncontrol,
do
not
confuse
the
throttle
position
sensor
on
the
main
throttle
body
with
the
throt-
tle
position
switch
on
the
secondary
throttle
body
.

27
Lb
2L4
LJ
22
©©®®17
©©®©©~©©®©~~rui~~ru

®®®®®®®®®®®®®®®IZA®®®®®®®®®®®®®®®®®

1
>I-
0013211

ECM
PIN
ASSIGNMENTS

130-
2
8



FUEL
INJECTION

Tableh
.
ECM
Pin
Assignment-Bosch
DME
M1
.7

Pin
Signal
Componenttfunction



Signal

1



Output



Fuel
pump
relay
control



Fuel
pump
relay,
terminal
85

2



Not
used

3



Output



Cyl
.
2
and
cyl
.
4
fuel
injection
valve
control



Cyl
.
2
and
cyl
.
4
fuel
injection
valves
4



Not
used

5



Not
used

6



Ground



Ground,
fuel
injection
valveoutputstages



Ground
point

7



Not
used

8



Output



"Check
engine"
indicator
control



Instrument
cluster

9



Not
used

10



Not
used

11



Output



DKV
potentiometer
signal



Transmission
control
module
(EGS)

12



Input



Throttleposition
sensor



Throttleposition
Signal

13



Not
used

14



Input



Volume
air
flow
sensor



Volume
air
flow
sensor
(signal
ground)

15



Input



Cyl
.
1-2
knock
sensor



Cyl
.
1-2
knock
sensor

16



Input



Camshaft
position
sensor
(cylinder
identification)



Camshaft
position
sensor
(cylinder
identification)

17



Output



ti
measurement
signal
(fuel
consumption)



Instrument
cluster

18



Output



Intakeair
resonance
changeover
valve
(DISA)



Intake
air
resonance
changeover
valve
19



-



Not
used

20



Not
used

21



Not
used

22



Not
used

23



Not
used

24



Output



Cyl
.
3
ignition
coil
control



Cyl
.
3
ignition
coil

25



Output



Cyl
.
1
ignition
coil
control



Cyl
.
1
ignition
coil

26



Input



Battery
voltage



B
+junction
point

27



Output



Engine
control
module
relay
control



Engine
control
module
relay,
terminal
85
28



Ground



Ground
for
electronics
and
shielding
of
sensors



Ground
point

29



Output



Idle
speed
control
valve
control



Idle
speed
control
valve

30



Not
used

31



Not
used

32



Output



Cyl
.
1
and
cyl
.
3
fuel
injection
valve
control



Cyl
.
1
and
cyl
.
3
fuel
injection
valves

33



Not
used
34



Ground



Ground,
output
stages
(except
for
ignition
and
fuel



Ground
point
injection
valves)

35



Not
used

36



Output



Evaporative
emissionvalve
control



Evaporative
emission
valve

37



Output



Oxygen
sensor
heater
control



Oxygen
sensor
relay,
terminal
85
38



Not
used
39



Not
used
40



I
Not
used

41



I
Input



,
Volume
Air
Flow
sensor



Volume
air
flow
sensor
(voltage
varies
with
engine
load)

42



1
Input



1
Cyl
.
3-4
knock
sensor



1
Cyl
.
3-4
knock
sensor

43



Ground



Ground
for
sensors



Engine
coolant
temperature
sensor,
cyl
.
1-2
knock
sensor,
cyl
.
3-4
knock
sensor,
and
throttle
position
sensor

44



1
Input



1
Camshaft
position
sensor
(cylinder
identification)



1
Camshaft
position
sensor
(cylinder
identification)

ECM
PIN
ASSIGNMENTS

Tableh
.
ECM
Pin
Assignment--Bosch
DME
M1
.7

Pin



1
Signal



1
Component/function



1
Signal

45
Notused

46
Notused

47
Notused

48



Output



A/C
compressor
cut-out



Compressor
control
relay,
terminal
85
49
Notused

50
Notused

51



Output



Cyl
.
4
ignition
coil
control



Cyl
.
4
ignition
coil

52



Output



Cyl
.
2
ignition
coil
control



Cyl
.
2
ignition
coil

53



Not
used
54



Input



Battery
voltage
from
engine
control
module



Engine
control
module
relay,
terminal
87a

55



Ground



Ground,
ignition



Ground
point

56



Input



Ignition
switch,
terminal
15



Ignition
switch,
terminal
15
57
Notused

58



Not
used

59



Output



Throttleposition
sensor
and
volume
air
flow
sensor



Reference
voltage
(5
VDC)

60



Input



Programming
voltage



Data
link
connector

61
Notused

62
Notused

63
Notused

64



Input



Ignition
timing
intervention



Transmission
control
module
(EGS)

65



Input



Drive
range
P/N



Automatic
transmission
range
switch

66
Notused

67



Input



Crankshaft
position
RPM
sensor



Crankshaft
position
RPM
sensor

68



Input



Crankshaft
position
RPM
sensor



Crankshaft
position
RPM
sensor

69
Notused

70



Input



Oxygen
sensor
signal



Heated
oxygen
sensor

71



Ground



Oxygen
sensor
signal
ground



Heated
oxygen
sensor

72
Notused

73



Input



Vehicle
speed
signal



Instrument
cluster

74



Output



Engine
speed
signal



Instrument
cluster

75



Not
used
76



Input



Volume
air
flow
sensor



Volume
air
flow
sensor

77



Input



Intake
air
temperature
sensor
(IAT)



Intake
air
temperature
sensor
(IAT)

78



Input



Engine
coolant
temperature



Engine
coolant
temperature
sensor

79
Notused

80



Not
used

81



Input



Drive-away
protection
signal
(code)



On-boardcomputer

82



Not
used
83
Notused

84



Not
used
85



Input



A/C
pressure



Pressure
switch

86



Input



A/C
switch



Integrated
climate
regulation
control
module

87



Output



RxD
diagnosisdata
line



Data
link
connector

88



Output-Input



TxD
diagnosisdata
line



l
Data
link
connector

FUEL
INJECTION



130-
2
9

ECM
PIN
ASSIGNMENTS

130-
3
0



FUEL
INJECTION

Pin
Signal
Component/function



Signal

ECM
PIN
ASSIGNMENTS

Table
1.
ECM
Pin
Assignment-Bosch
DME
M3
.1

1



output



Fuel
pump
relay
control



Fuel
pump
relay
switches
with
engine
runningor
cranking
(crankshaft
position
Signal
mustbe
present
for
relay
switchover)

2



1
output



1
Idle
speed
control
valve



1
Pulsad
ground-
close
signal
(seealsopin29)

3



output



Fuel
injectorcontrol,
cyl
.
1



Pulsedground
(injection
pulsewidth
in
ms)
with
engine
running

4



output



Fuel
injectorcontrol,
cyl
.
3



Pulsedground
(injection
pulsewidth
in
ms)
with
engine
running
5



output



Fuel
injector
control,
cyl
.
2



Pulsedground
(injection
pulse
width
in
ms)
with
enginerunning

6



ground



Ground



Ground
for
fuel
injector
output
stages

7
vacant
-



-

8



output



Check
Engine



Check
éngine
lamp
control
ground

9
vacant
-



-

10
vacant
-



-

11



output



Throttle
valve
position



Load
signal
to
transmission
control
module
12



input



Throttle
position
sensor



Voltage
varies
with
throttle
position

13



output



Mass
air
flow
sensor



Air
flow
sensor
hotwire
burn
off
(voltage
for
0
.5
seconds
after
shutdown)

14



ground



Mass
air
flow
sensor



Ground
for
air
flow
sensor

15
vacant
-



-

16



input



Cylinder
identification
sensor



A/C
voltage
pulse
per
camshaft
revolution
(between
pin
16
and
44)
17



output



Fuel
consumption
(ti)



Fuel
consumption
output
(KVA
Signal)
to
instrument
cluster

18
vacant
-



-

19
vacant
-



-

20
vacant
-



-

21vacant
-



-

22
vacant
-



-

23



output



Ignition
control
(terminal
1),
cyl
.
no
.
2



Primary
Signal,
ignition
coil
cyl
.
no
.
2

24



output



Ignition
control
(terminal
1),
cyl
.
n
o
.
3



Primary
signal,
ignition
coil
cyl
.
no
.
3

25



output



Ignition
control
(terminal
1),
cyl
.
n
o
.
1



Primary
signal,
ignitioh
coil
cyl
.
no
.
1

26



input



Power
supply
(terminal
30)



Battery
voltage
(B+)
at
al¡
times
(terminal
30)

27



output



Main
relay
control



Main
relay
activation
(to
relay
terminal
85)

28



ground



Ground



Ground
for
ECM
and
sensor
shielding

29



output



Idle
speed
control
valve



Pulsed
ground-
open
signal
(see
also
pin
2)

30
vacant
-



-

31



output



Fuel
injector,cyl
.
no
.
5



Pulsedground
(injection
pulsewidth
in
ms),
cyl
.
no
.
5

32



output



Fuel
injector,cyl
.
no
.
6



Pulsedground
(injection
pulse
width
in
ms),
cyl
.
no
.
6

33



output



Fuel
injector,cyl
.
no
.
4



Pulsedground
(injection
pulsewidth
in
ms),
cyl
.
no
.
4

34



ground



Ground



Ground
for
output
stages

35
vacant

36



output



Evaporative
purgevalve
control



Pulsed
ground
with
engine
at
normal
temperature
and
varying
engine
load

37



output



Oxygen
sensor
heater
relay
control



Oxygen
sensor
heater
relayactivation
(ground
at
terminal
85)

38
vacant
-



-

39
vacant
-



-

40
vacant



-

41



input



Mass
air
flow
sensor



Voltage
(+)

42
vacant
-



-

43



ground



Ground



Ground
for
temperatura
sensors
(ECT
sensor,
IAT
sensor,
TP
sensor)

44



input



Cylinder
identification
sensor



A/C
voltagepulseper
camshaft
revolution
(between
pin
16
and
44)