Mass air flow sensor BMW 325i 1994 E36 User Guide

GENERAL
.
.
.
.
.
.
.
.
.
...
.
.
.
.
.
.
.
.........
130-2



Intake
air
temperature
(IAT)
sensor,

Principles
of
Operatinn
.
.
.
.
.
.
.
.
.
.........
130-2



testing
and
replacing
...
.
...
.
.
.
.......
.
130-19

Basic
Engine
Settings
.
.
.
.
.
.
.
.
.
.
.
.
.
.
...
:
.
130-3



Throttle
position
sensor
(TPS),

DISA
(Dual
Resonance
Intake
System)
.
.
.
.
.
130-3



testing
and
replacing
...
.
...
.
.
.
.
.
...
.
.
.130-19

On-Board
Diagnostics
(OBD)



Idle
speed
control
valve,
testing
.
.
.
.
.
.
.
.
.
.
130-20

and
Fault
Diagnosis
.
.
....
.
......
.
.
.
...
130-4



Idle
speed
control
valve,
replacing
.
.
.
.
.
.
..
130-21

SecondaryAir
Injection
.
.
.....
.
.........
.
130-5



BOSCH
DME
M5
.2
COMPONENT
Warnings
and
Cautions
.
.
...
.
.
.
.........
.
130-6



REPLACEMENT
.....
.
......
.
....
.
.
.
..
130-21

ELECTRICAL
CHECKSAND



Mass
air
flow
sensor,
replacing
.
.
....
.
....
130-22

COMPONENT
TESTING
.
.
.
.
.
.
.
.
...
.
.
.
.
.
130-7



Engine
coolant
temperature
(ECT)

Main



sensor,
replacing
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
130-22
rela
y
testing



130
-7
,...
.
.
.
.
.
.
.
.
.
...
.
.
.
.
.
.
.



Intake
air
temperature
(IAT)
sensor,
Fuel
pump
relay,
testing
.
.
.
.
.
.
.
...
.
.
.
.
.
.
.
130-7



rep
lacin
.
.
.
.
.
.
.
.
.
.
.g



.
.
.
.
.
.
.
...
.
.
.
..
.130-22
Oxygen
sensor,
testing
(Boschsystems
only)
130-8



Throttle
poson
sensor
(TPS)
replacing



13022
,



..
.-

FUEL
DELIVERY
TESTS
...
.
....
.
.
.
...
.
130-9



Idle
speed
control
valve,
replacing
...
.
....
.130-23

Operating
fuel
pump
for
tests
.
.
.......
.
...
130-9



SIEMENS
MS
41
.1
COMPONENT
Relieving
fuel
pressure
and



REPLACEMENT
.
...
.
.
.
.
.
.......
.
....
.130-23
connecting
fuel
pressure
gauge
......
.
..
130-10

Residual
fuel
pressure,
testing
.
.....
.
.
.
.
.
130-10



Mass
air
flow
sensor,
replacing
.
.......
.
.
.130-25

Fuel
pressure
regulator
response



Engine
coolant
temperature
(ECT)

to
engine
load,
testing
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
130-11



sensor,
replacing
.....
.
.
.
.
.
.........
.130-25

Fuel
rail
and
injectors,
checking
...
.
.
.
.
.
.
.
130-11



Intake
air
temperature
(IAT)
sensor,
replacing
.
.
.
.
.
.....
.
.
.
.
.
.
.
.......
.
.
.130-25
Fuel
rail
and
injectors,
replacing



..
.
.
.
.
.
.
.
130-12



Throttleposition
sensor
(TPS),
replacing
.
.
.
130-26
Fuel
PressureRegulator
.........
.
.
.
.
.
.
.
130-13



Idle
s
eed
control
valve,
re
lacin



130-26
Fuel
pressure
regulatorreplacing



p



p



g
.'''...
.
'
,

(fuel
rail
mount)
...
.
.
.
.
.
.............
130-13



ECM
PIN
ASSIGNMENTS
.............
.
.
130-26
Fuel
pressure
regulator,
replacing



Engine
control
module
(ECM),
accessing
...
130-26
(undercar
mount)
.
.
.
.
.
.
.
.
.........
.
.
130-14

BOSCH
DME
M1
.7
COMPONENT

TESTS
AND
REPAIRS
.
.
.
.
.
...
.
.
.
.
.
.
.
.
130-14

Air
flow
sensor,
testing
and
replacing
.
.
.
.
.
.
130-14

Engine
coolant
temperature
(ECT)

sensor,
testing
and
replacing
...
.
.
.
.
.
.
.
.
130-15

Throttle
position
sensor
(TPS),

testing
and
replacing
.
..........
.
.....
130-16

Idle
speed
control
valve,
testing
and
replacing
.
.
.
.
.
............
130-16

BOSCH
DME
M3
.1
AND
M33
.1

COMPONENT
TESTS
AND
REPAIRS
.
.
.
130-17

Mass
Air
Flow
Sensor
.
.
.
.
.
.
.
.
.....
.
.
.
.
.130-17

Mass
air
flow
sensor
(hotwire),testing
and
replacing
.
.
.
.
.
.....
.
.
.
.
.
.
.
130-17

Mass
air
flow
sensor
(hot
film),

testíng
and
replacing
.
.
.
.....
.
.
.
.
.
.
.
.
.
130-18
Engine
coolant
temperature
(ECT)

sensor,
testing
and
replacing
..
.
.
.
.
.
...
.
130-18

130
Fuel
i
n
jection

FUEL
INJECTION



130-1

TABLES
a
.
Engine
Management
System
Variants
.........
.130-2
b
.
Mass
Air
Flow
Sensor
Variants
..
.
..
..........
.130-2
c
.
Fuel
Pressure
Specifications
..
.
.
...
..........
130-11
d
.
Engine
Coolant
Temperature
Sensor
or
Intake
Air
Temperature
Sensor
Test
Values
(DME
1
.7)
...
.
130-15
e
.
ThrottlePosition
Sensor
Tests
(DME
1
.7)
......
.130-16
f
.



Engine
Coolant
Temperature
Sensor
or
Intake
Air

Temperature
Sensor
Test
Values
(DME
3
.1/3
.3
.1)130-19
g
.
Throttle
Position
Sensor
Tests
(DME
3
.1/3.3
.1)
.
.130-20
h
.
ECM
Pin
Assignment-Bosch
DME
M1
.7
....
.
..
.130-28
i.



ECM
Pin
Assignment-Bosch
DME
M3
.1
.......
.130-30
j
.



ECM
Pin
Assignment-Bosch
DME
M3
.3
.1
.....
.130-32
k
.
ECM
Pin
Assignment-Bosch
DME
M5
.2
.......
.
130-34
I.



ECM
Pin
Assignment-Siemens
DME
MS
41
.1
..
.
130-36

130-2



FUEL
INJECTION

GENERAL

This
repair
group
covers
fuel
injection
system
component

testing
and
repair
.
Special
equipment
is
necessary
for
some

of
the
procedures
given
in
this
repair
group
.
If
you
do
not
have

the
equipment
required
to
do
the
job,
it
is
recommended
that

these
repairs
be
left
to
an
authorized
BMW
dealer
.
The
BMW

dealer
is
equipped
with
sophisticated
diagnostic
test
equip-

ment
that
is
capable
of
quicklypinpointing
hard-to-find
fuel
in-

jection
problems
.

NOTE-

"
Wiring
diagrams
for
the
engine
management
system,

can
be
found
at
the
rear
of
the
manual
under
Electri-
cal
Wiring
Diagrams
.

"
For
ignition
system
repairinformation,
see120
Igni-

tion
System
.

"
For
fuel
supply
system
testing
and
repair,
see160



The
engine
control
module
(ECM)
uses
electrical
signals

Fuel
Tank
and
Fuel
Pump
.



from
the
mass
air
flow
sensor,
the
air
and
coolant
temperature

sensors,
the
crankshaft
position/rpm
sensor,
the
knock
sen

Principies
Of
Operation



sors
and
the
oxygen
sensorsas
the
primary
inputs
to
electron-

ically
control
fuel
delivery
and
ignition
timing
.

There
are
five
versions
of
engine
management
systems

usedon
the
E36
cars
.
Each
has
the
same
basic
components

and
operating
principles
.
The
most
notable
difference
is
that

1996
and
later
cars
use
a
sophisticated
OBD
II-compliant
sys-

tem
.
See
Table
a
.

Table
a
.
Engine
Management
System
Variants

Engine
code/year



1
System

4-cy1inder
M42
(1
.8
I)
1992-1995



Bosch
DME
Ml
.7
M44
(1
.91)
1996-1998



~
Bosch
DME
M5
.2
(OBD
II)

6-cylinder
M50
1992
(2.5
I)



Bosch
DME
M3
.1
1993-1995
(2.5
I)



Bosch
DME
M3
.3.1
(VANOS)
M52
1996-1998
(3281-
2
.8
I)



Siemens
MS
41
.1
(OBD
II)
1998
(3231
-
2
.5
I)



Siemens
MS
41
.1
(OBD
II)
M-Power
S50US
(M3
-
3
.01)
1995



Bosch
DME
M3
.3
.1
S52US
(M3
-
3
.21)
1997-1998



Siemens
MS
41
.1
(0131)
11)

NOTE-

-
Descriptions
and
procedures
in
the
first
partof
this
re-

pairgroup
refer
to
all
the
various
engine
management
systems
.

"
Particulars
of
each
fuel
injection
system
are
treated
in
separate
sections
in
the
second
part
of
this
repair
group
.

GENERAL

Fig
.1
.



OBD
II
diagnostic
connector
locatíon
.

The
fuel
injection
system
is
completely
electronic
in
opera-

tion
.
Air
flow
is
measured
electronically
via
a
mass
air
flow

sensor
and
additional
sensors
supply
information
about
en-

gine
operating
conditions
.
The
ECM
calculates
the
amount
of
fuel
needed
for
the
correct
air-fuel
ratio
and
actuates
the
fuel

injectors
accordingly
.
The
amount
offuel
metered
to
theen-

gine
is
determined
by
how
long
the
injectors
are
open
.

Airintake
.
Air
entering
the
engine
passes
through
a
pleat-

ed
paper
air
filter
in
the
air
cleaner
.
Intake
air
volume
or
mass

is
then
measured
bya
mass
air
flow
(MAF)
sensor
.
In
al¡
ex-

cept
the
vane
type
sensor
(DME
M1
.7),
a
reference
current
is

used
to
heat
a
thin
wireor
film
in
the
sensor
when
the
engine

is
running
.
The
current
used
to
heat
the
wire/film
is
electroni-

cally
converted
into
a
voltage
measurement
corresponding
to

the
mass
of
the
intake
air
.

Table
b
.
Mass
Air
Flow
Sensor
Variants

System



Al
r
flow
sensor
type

Bosch
DME
M1
.7



Vane
(volume
sensor)

Bosch
DME
M3
.1



Hot
wire
(mass
sensor)

Bosch
DME
M3
.3
.1



Hot
film
(mass
sensor)

Bosch
DME
M5
.2



Hot
film
(mass
sensor)

Siemens
MS
41
.1



Hot
film
(mass
sensor)

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



NOTE-

the
lower
left
dashpanel
.
See
Fig
.
1
.



On
cars
equipped
wíth
tractioncontrol,
an
additional
throttle
valve
is
controlled
by
an
electronic
throttle
actu-
ator
(motor)
.
This
valve
is
used
for
engine
speed
inter
vention
.
Repair
information
forthis
system
is
notcovered
here
due
to
the
special
electrical
testing
equip-
ment
required
to
service
it
.

BOSCH
DME
MM
AND
M33
.1

COMPONENT
TESTS
AND
REPAIRS

Consult
Table
a
for
engine
application
information
for
the

Bosch
DME
3
.1
and
3
.3.1
systems
.

The
DME
3
.1
and
DME
3
.3
.1
systems
are
similar
in
opera-

tion,
with
knock
control
and
VANOS
operation
being
the
key

differences
.
DME
3
.1
engines
arenot
equipped
with
VANOS

or
knock
detectors,
while
the
DM
E3
.3
.1
system
is
.

CA
UTION-

Use
onty
a
digital
multimeter
when
testing
wiring
.
Use
of
an
analog
VOM
may
damage
the
engine
control
module
.

Fig
.
25
.
Mass
air
flow
sensor
.
Hot
wire
sensor
usedon
carswith
DME
Electrical
tests
of
the
main
and
fuel
pump
relays
and
the



3
.1
(1992
6-cylinder
models)
.

DME
engine
control
module
(ECM)
are
covered
earlier
in
this

section
.
Fuel
pump
tests
are
covered
in
160
Fuel
Tank
and



CAUTION-
Fuel
Pump
.
Use
only
a
digital
multimeter
when
checking
the
mass
air
flow
sensor
.
An
analog
meter
can
dam-
Mass
Air
Flow
Sensor



age
theair
flow
sensor
.

There
are
two
types
of
mass
air
flow
sensors
used
onthe



1
.
Disconnect
air
flow
sensor
from
air
cleaner
only
.
Leave

cars
covered
by
this
section
.
Testing
procedures
vary
de-



it
connected
to
duct
leading
to
intake
manifold
and

pending
on
type
installed
.
The
airflow
sensor
is
not
adjustable



leave
wiring
harness
connected
.

and
must
only
be
tested
with
a
digital
multimeter
.

Mass
Air
FlowSensor
Variants

"
1992
M50
engine

DME
M3
.1
.
.
.
.
...
..
mass
air
flow
sensor-hot
wire

"
1993-1995
M50
and
S50US

DMEM33
.1)
.
...
...
.
mass
air
flow
sensor-hot
film

Mass
air
flow
sensor
(hot
wire),

testing
and
replacing

When
the
engine
is
running,
a
current
is
used
to
heat
a
thin

wire
in
the
center
of
the
sensor
.
See
Fig
.
25
.
The
current
in
the

wire
is
regulated
to
maintain
a
temperature
of
100°C
more

than
the
air
passing
over
it
.
The
current
used
to
heat
the
wire

is
electronically
conneced
into
a
voltage
measurement
corre-

sponding
to
the
mass
of
intake
a¡
r
.

To
keep
the
wire
clean,
it
is
heated
to
a
temperature
of
about

1,000°C
(1,830°F)
for
one
second
.
This
"burn-off"
cycle
takes

place
automatically,
four
seconds
after
the
engine
is
tumed
off
.

lf
thehot
wire
breaks
or
if
there
is
no
output
from
the
air
flow

sensor,
the
ECM
automatically
switches
to
a
"limp-home"

mode
and
tucos
on
the
Check
Engine
light
.
The
engine
can

usually
be
started
and
driven
.
The
air
flow
sensor
has
no
inter-

nal
moving
parts
and
cannot
be
serviced
.

FUEL
INJECTION



130-
1
7

2
.
Start
engine
and
run
it
to
normal
operating
temperature
.

3
.
Rev
engine
toat
least
2,500
rpm,then
shut
it
off
.
Look

through
meter
at
hot
wire
.
After
approximately
four
sec-

onds
wire
should
glow
brightly
for
about
one
second
.

NOTE
-

If
the
wire
glowsas
specified,
then
the
airflow
meter
and
ECM
are
probably
operating
correctly
.
lf
the
wire
does
not
glow,
continue
testing
.

4
.
lf
the
wire
does
not
glow,
remove
air
flow
sensor
and

look
through
it
to
see
if
wire
is
broken
.
lf
wire
is
broken,

meter
will
have
to
be
replaced
.

5
.
Reinstall
air
flow
sensor
and
harness
connector
.
Peel

back
rubber
bootfrom
harness
connector
.
Working

from
rear
of
connector,
connect
digital
voltmeter
across

terminals
1
and
4
.
See
Fig
.
26
.

6
.
Start
and
rev
engine
toat
least
2,500
rpm,thenshut
it

off
.
After
about
4
seconds,
voltage
should
riseto
about

4
volts
for
about
one
second
.
lf
voltage
is
present,
but

wire
does
not
glow,
air
flow
sensor
is
faulty
and
should

be
replaced
.

7
.
lf
voltage
is
not
present
in
step
6,
turn
ignition
key
on

and
check
for
voltage
and
ground
at
sensor
.
There

should
beground
at
pin
4
.
There
should
be
positive
(+)

battery
voltage
at
pin
2
.

BOSCH
DME
M3
.1
AND
M32
.1
COMPONENT
TESTS
AND
REPAIRS

130-18



FUEL
INJECTION
The
engine
coolant
temperature
(ECT)
sensor
sends
con-

tinuous
engine
coolant
temperature
information
to
the
ECM
.
Fig
.
26
.
Mass
air
flow
sensor
terminalidentifcation
on
carswith
DME



As
temperature
increases
sensor
resistance
decreases
.
M3
.1
fuel
injection
.

Mass
air
flow
sensor
(hot
film),

testing
and
replacing

MOTE-

A
burn-off
cycle
is
not
used
on
hot
film
sensors
.

8
.
With
ignition
off,
disconnect
harness
connector
from
air



ECT
Sensor
Location
flow
sensor
.
Using
a
digital
multimeter,
check
resis-



"
M50/S50US
engine
............
left
side
of
cylinder
tance
at
terminals
listed
.



head
under
intake
manifold

Air
Flow
Sensor
Test
Values
(DMEM3
.1)

"
Terminals
5
and
6
.
.
.
.........
..
.
..
....
3-4
ohms

If
any
faults
are
found,
check
wiring
lo
and
from
the
ECM
.
Make
ECM
pinout
test
as
listed
in
See
Table
i
.
Main
power
to
air
flow
sensor
comes
from
DME
main
relay
.

On
cars
with
DME
M3
.3
.1
a
hot
film
mass
air
flow
sensor
is
used
.
When
the
engine
is
running,
a
current
is
used
lo
heat
a
thinfilm
in
the
center
of
the
sensor
.
This
current
is
electroni-
cally
converted
into
a
voltage
measurement
corresponding
to
the
mass
of
intake
air
.

If
thehot
film
breaks
or
if
there
is
no
output
from
the
air
flow
sensor,
the
ECM
automatically
switches
to
a
"limp-home"
mode
and
tucos
on
the
Check
Engine
light
.
The
engine
can
usually
be
started
and
driven
.
The
air
flow
sensor
has
no
inter-
nal
moving
parts
and
cannot
be
senricedor
adjusted
.

CA
UTION-

Use
only
a
digital
multimeter
when
checking
the
mass
air
flow
sensor
.
An
analogmetercan
dam-
age
the
air
flow
sensor
.

BOSCH
DME
M3
.
1
AND
M32
.1
COMPONENT
TESTS
AND
REPAIRS

1
.
Disconnect
harnessconnector
from
air
flow
sensor
.

2
.
Turn
ignition
on
and
check
for
voltage
and
ground
at

connector
.
There
should
beground
at
pin
1
.
There

should
be
positive
(+)
battery
voltage
at
pin
3
.
If
any
faults
are
found,
check
wiring
to
and
from
ECM
.
Make
ECM
pinout
test
.
See
Table
j
.

NOTE-

Positive
(+)
battery
voltage
to
air
flow
sensor
comes
from
DME
main
relay
when
the
ignition
is
switch
on
orengine
running
.

Engine
coolant
temperature
(ECT)
sensor,

testing
and
replacing

0012704
Fig
.
27
.
Engine
coolant
temperature
(ECT)
sensor
(A)
is
located
be-
neath
top
engine
cover
(B)
and
crankcase
vent
hose
(C)
.
M52
engine
shown
.
M50
is
similar
.

1
.
Check
ECM
reference
voltage
to
sensor
:
"
Disconnect
harnessconnector
from
ECT
sensor
.
"
Turn
ignition
keyon
.
"
Check
for
5
volts
between
supply
voltage
wire
(brown/red)
wire
of
harness
connector
and
ground
.
"
Turn
ignition
key
off
.
"
If
voltage
is'
not
present
or
incorrect,
check
wiring
from
ECM
and
check
referencevoltage
output
at
ECM
(pin
78)
.
See
Table
i
(DM
E
3
.1)
or
Table
j
(DME
3
.3
.1)

2
.
Check
ECT
sensor
resistance
:

"
With
harnessconnector
disconnected,
check
resis-
tance
acrosssensor
terminals
.
"
Compare
tests
results
to
values
in
Table
f
.

130-
2
2



FUEL
INJECTION

Mass
air
flow
sensor,
replacing

1
.
Disconnect
harness
connector
and
intake
air
bootfrom

air
flow
sensor
.
See
Fig
.
32
.

Fig
.
32
.
To
detach
air
flow
sensor,
disconnect
harness
connector
(A)
;



3
.
Installation
is
reverse
of
removal
.
unclip
retainíng
clips
to
aír
filter
housing
(B)
;
andremove
large
hose
clamp
at
air
intake
bellows
(C)
.
M44
engine
with
traction



"
Use
a
new
copper
sealing
washer
when
installing
sen-

control
shown
.



sor
.
"
Replace
any
lost
coolant
.

2
.
Detachtwo
large
clipsat
air
filter
housing
and
work
air

flow
sensor
out
of
rubber
seal
in
filter
housing
.
Tightening
Torque

3
.
Installation
is
reverse
of
removal
.



"
Engine
coolant
temperature

"
For
ease
of
installation,
lubricate
large
rubber
seal
in



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

air
filter
housing
with
silicone
lubricant
or
equivalent
.
"
No
adjustment
to
air
flow
sensor
is
possible
.
"
Carefully
check
that
all
hoses
and
seals
are
seated



Intake
air
temperature
(IAT)
sensor,

properly
.



replacing

Engine
coolant
temperature
(ECT)
sensor,

replacing

The
engine
coolant
temperature
(ECT)sensor
is
a
dual
temperature
sensor
.
One
circuít
provides
coolant
temperature

information
to
the
ECM
while
the
other
circuít
provides
coolant
temperature
information
to
the
instrument
cluster
.

WARNING
-

Do
not
replace
the
ECT
sensor
unless
the
engine
is
cold
.
Hot
coolant
can
scald
.

1
.
Disconnect
harness
connector
from
ECT
sensor
.
See
Fig
.
33
.

2
.
Unscrew
temperature
sensorfrom
cylinder
head
and
remove

BOSCH
DME
M5
.2
COMPONENT
REPLACEMENT

U1111
bis4a

Fig
.
33
.
M44
engine
coolant
temperature
(ECT)
sensor
located
above

oil
filter
(arrow)
.

The
intake
air
temperature
(IAT)
sensoron
cars
with
M44

engine
is
mounted
in
thetop
section
of
the
intake
air
filter

housing
.
See
Fig
.
34
.

1
.
Remove
electrical
harness
connector
from
IAT
sensor
.

2
.
Unclip
temperature
sensor
and
remove
from
air
filter

housing
.

3
.
Installation
is
reverse
of
removal
.

Throttle
position
sensor
(TPS),
replacing

The
throttle
position
sensor
is
located
on
the
side
of
the
throttle
housing
.
See
Fig
.
35
.

1
.
Unplug
harness
connector
from
sensor
.

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-
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)

130-
3
2



FUEL
INJECTION

Pin



1
Signal



1
Component/function



1
Signal

1



output



Fuel
pump
relay
control



Fuel
pump
relay
switches
with
engine
running
or
cranking
(crankshaft
position
signal
must
be
present
for
relay
switchover)

2



output



Idle
speed
control
valve



Pulsed
ground-close
signal
(seealso
pin
29)

3



output



Fuel
ínjectorcontrol,
cyl
.
5



Pulsed
ground
(injection
pulsewidth
in
ms)
cyl
.
5
4



output



Fuel
injectorcontrol,
cyl
.
6



Pulsed
ground
(injection
pulsewidth
in
ms)
cyl
.
6
5



output



Fuel
injectorcontrol,
cyl
.
4



Pulsed
ground
(injection
pulsewidth
in
ms)
cyl
.
4
6



ground



Ground



Ground
for
fuel
injector
output
stage

7



output



Camshaft
actuator
(VANOS
solenoid)
control



Camshaft
actuator
(VANOS
solenoid)

8



output



Check
Engine



Instrument
cluster,
Check
Engine
lamp

9
vacant
-



-

10
vacant
-



-

11



output



Throttle
position



Throttle
angle
signal
to
A/T
control
module
12
vacant
-



-

13



input



Oxygen
sensor



Oxygen
sensor
signal
(0-1
VDC
fluctuating
with
engine
running)

14



input



Mass
air
flow
sensor



Mass
air
flow
sensor

15
ground
Ground



Ground

16



input



Crankshaft
position/rpm
sensor



Voltage
pulse
(VAC)
between
pin
16
and
43
(crank
position/rpm
sensor)

17



input



Camshaft
position
sensor



Halleffect
camshaft
sensor

18
vacant
-



-

19
vacant
-



-

20
vacant
-



-

21
vacant
-



-

22
vacant
-



-

23



output



Ignition
coil
control,
cyl
.
4



Ignition
coil
4

24



output



Ignition
coil
control,
cyl
.
6



Ignition
coil
6

25



output



Ignition
coil
control,
cyl
.
5



Ignition
coil
5

26



input



Power
supply
(terminal
30)



Battery
voltage(B+)
at
all
times

27



input



Main
relay
control



Main
relayactivation
(terminal
85)

28



ground



Ground



Ground
for
ECM
and
sensor
shielding

29



output



Idle
speed
control
valve



Pulsed
ground-open
signal
(seealsopin
2)

30
vacant
-



-

31



output



Fuel
injectorcontrol,
cyl
.
3



Injection
pulse
wicith
in
ms-cyl
.
3

32



output



Fuel
injectorcontrol,
cyl
.
2



Injection
pulse
wicith
in
ms-cyl
.
2

33



output



Fuel
injectorcontrol,
cyl
.
1



Injection
pulsewidth
in
ms-cyl
.
1

34



ground



Ground



Ground
for
remaining
output
stages

35
vacant
-



-

36



output



Evaporative
purge
valve
control

37
vacant
-



-

38



output



Oxygen
sensor
heater
relay
control



Oxygen
sensor
heater
relay
switchover
(terminal
85)

39
vacant
-



-

40



ground



Oxygen
sensor



Oxygen
sensor
signal
ground

41



input



Mass
air
flow
sensor



Mass
air
flow
voltage
signal

42



input



Vehicle
speed



Vehicle
speed
signal
from
instrument
cluster

43



input



Crankshaft
position/rpm
sensor



Voltage
pulse
(VAC)
between
pin16
and
43
44



ground



Ground



Ground
for
intake
air
temp
.
sensor,
engine
coolant
temp
.
sensor,
throttle
position
sensor

ECM
PIN
ASSIGNMENTS

Table
j
.
ECM
Pin
Assignment-Bosch
DME
M3
.3
.1

130-
34



FUEL
INJECTION

Pin



i
Signal



1
Component/function



1
Signal

1



output



Oxygen
sensor
(monitoring
sensor)heater



Oxygen
sensor
heater
control
(switched
ground)

2



output



Idle
speed
control
valve



Pulsed
ground-close
signal
(see
also
pin
29)

3



output



Fuel
injector
control,
cyl
.
1



Pulsed
ground
(injection
pulsewidth
in
ms)
cyl
.
1

4



output



Fuel
injector
control,
cyl
.
4



Pulsed
ground
(injection
pulse
width
in
ms)
cyl
.
4

5



not
used



-



-

6



ground



Ground



Ground
for
fuel
injector
output
stage

7



not
used



-

8



1
output



1
Check
Engine



1
Instrument
cluster,
Check
Engine
lamp

9



not
used



-



-

10



input



Electronic
immobilizer
control
(EWS
II)



Electronic
immobilizer
control
(EWS
II)
module

11



output



Automatic
climate
control



Automatic
climate
control,
to
evaporator
controlier

12



not
used



-



-

13



not
used



-



-

14



not
used



-



-

15



not
used



-



-

16



input



Intake
air
temperature



Intake
air
temperature
Signal

17



input



Mass
air
flow
meter



Intake
air
signal

18



not
used



-



-

19



input



Oxygen
sensor
(monitoring
sensor)



Oxygen
sensor
control

20



output



Crankshaft/rpm
sensor



Crankshaft/rpm
sensor
control

21



input



Camshaft
position
sensor



Camshaft
position
signal

22



output



Ignition
coil
control,
cyl
.
3



Primary
signal,
ignitioncoil
3

23



output



Ignition
coil
control,
cyl
.
4



Primary
signal,
ignitioncoil
4

24



not
used



-



-

25



not
used



-



-

26



input



Power
supply
(terminal
30)



Battery
voltage
(B+)
at
al¡
times

27



input



Main
relay
control



Main
relay
activation
(terminal
85)

28



ground



Ground



Ground
for
ECM
and
sensor
shielding

29



output



Idle
speed
control
valve



Pulsed
ground-open
signal
(seealsopin
2)

30



output



Oxygen
sensor
(monitoring
sensor)
heater



Oxygen
sensor
heater
control
(switched
ground)

31



output



Fuel
injectorcontrol,
cyl
.
3



Pulsed
ground
(injection
pulsewidth
in
ms)
cyl
.
3

32



output



Fuel
injector
control,
cyl
.
2



Pulsed
ground
(injection
pulsewidth
in
ms)
cyl
.
2

33



I
not
used

40



input



Knock
sensor
#2
(cyl
.
3,4)



Knock
sensor
#2
signal

41



not
used



-



-

42



input



Vehicle
speed



Vehicle
speed
signal
from
instrument
cluster

43



not
used



-



-

44



output



Throttleposition
sensor
(TPS)



Throttleposition
reference
signal

ECM
PIN
ASSIGNMENTS

Table
k
.
ECM
Pin
Assignment-Bosch
DME
M5
.2

34



ground



Ground



Ground
for
ECM/
output
stages

35



not
used



-



-

36



input



A/C
compressor
relay



A/C
compressor
relay
control

37



not
used



-



-

38



not
used



-



-

39



not
used



-



-

Table
k
.
ECM
Pin
Assignment-Bosch
DME
M5
.2
(continued)

Pin



I
Signal



1
Componentltunction



1
Signal
45



I
output



I
Mass
air
flow
meter



I
Intake
airSignal

46



output



Oxygen
sensor
(monitoring
sensor)



Oxygen
sensor
control

47



not
used



-

48



not
used



-

49



output



Ignition
coil
control,
cyl
.
1



Primary
signal,
ignition
coil
1

50



output



Ignition
coil
control,
cyl
.
2



Primary
signal,
ignition
coil
2
51



not
used



-

52



not
used



-

53



input



Throttleposition
sensor



Throttleposition
Signal

54



input



Power
supply



Batteryvoltage
from
main
relay
(terminal
87)

55



ground



Ground



Ground
for
ECM

56



input



Power
supply
(terminal
15)



Battery
voltage
with
key
on
or
engine
running

57



output



Activate
cooling
fan
(man
.
trans
.)
control



Normal
speed
relay

58



not
used



-



-

59



not
used



-



-

60



input



Programming
voltage



Programming
voltage
via
data
link
connector,
pin
18

61



output



Evaporative
emissionvalve



Evaporative
emission
valve
control

62
vacant
-



-

63



output



Fuel
pump
relay



Fuel
pump
relay
control

64



not
used



-

65



not
used



-



-

66



not
used



-



-

67



not
used



-



-

68



input



Signal
above
80°C(man
.
tran
.)



Double
temperature
switch

69



input



Automatic
climate
control



Automatíc
climate
control

70



input



Knock
sensor
#1
(cyl
.
1,2)



Knock
sensor
#1
Signal

71



ground



Ground



Ground
for
analog
signals
and
knock
sensors

72



not
used



-



-

73



not
used



-



-

74



input



Engine
coolant
temperature
sensor



Engine
coolant
temperatura
Signal

75



not
used



-



-

76



not
used



-



-

77



output



Oxygen
sensor
(regulating
sensor)



Oxygen
sensor
control

78



input



Crankshaft/rpm
sensor



Crankshaft
position/rpmSignal

79



input



ABS
or
traction
control



ABS
or
AST
control

80



input



Engine
speed



Engine
speed
Signal
81



not
used



-



-

82



not
used



-



-

FUEL
INJECTION



130-
3
5

83



input



On-board
computar



From
On-boardcomputer
(terminal
4)

84



not
used



-



-

85



not
used



-



-

86



not
used



-



-

87



input



Diagnostic
connector
(RxD)



Diagnostic
RxD
(receive)signal
to
pin
15
in
Data
link
connector

88



output



I
Diagnostic
connector
(TxD)



Diagnostic
TxD
(transmit)
signal
to
pin
17in
Data
link
connector

ECM
PIN
ASSIGNMENTS