1994 BMW 318i Temperature control
[x] Cancel search: Temperature controlPage 147 of 759
GENERAL
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.........
130-2
Intake
air
temperature
(IAT)
sensor,
Principles
of
Operatinn
.
.
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.
.........
130-2
testing
and
replacing
...
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...
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.......
.
130-19
Basic
Engine
Settings
.
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...
:
.
130-3
Throttle
position
sensor
(TPS),
DISA
(Dual
Resonance
Intake
System)
.
.
.
.
.
130-3
testing
and
replacing
...
.
...
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...
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.
.130-19
On-Board
Diagnostics
(OBD)
Idle
speed
control
valve,
testing
.
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.
130-20
and
Fault
Diagnosis
.
.
....
.
......
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...
130-4
Idle
speed
control
valve,
replacing
.
.
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.
..
130-21
SecondaryAir
Injection
.
.
.....
.
.........
.
130-5
BOSCH
DME
M5
.2
COMPONENT
Warnings
and
Cautions
.
.
...
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.
.........
.
130-6
REPLACEMENT
.....
.
......
.
....
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..
130-21
ELECTRICAL
CHECKSAND
Mass
air
flow
sensor,
replacing
.
.
....
.
....
130-22
COMPONENT
TESTING
.
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...
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.
130-7
Engine
coolant
temperature
(ECT)
Main
sensor,
replacing
..
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.
130-22
rela
y
testing
130
-7
,...
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...
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.
Intake
air
temperature
(IAT)
sensor,
Fuel
pump
relay,
testing
.
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...
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130-7
rep
lacin
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.g
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...
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..
.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
.
...
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.......
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....
.130-23
connecting
fuel
pressure
gauge
......
.
..
130-10
Residual
fuel
pressure,
testing
.
.....
.
.
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.
130-10
Mass
air
flow
sensor,
replacing
.
.......
.
.
.130-25
Fuel
pressure
regulator
response
Engine
coolant
temperature
(ECT)
to
engine
load,
testing
.
.
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.
130-11
sensor,
replacing
.....
.
.
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.
.
.........
.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
.
.
.
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.
...
.
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.
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
.
.
.
.
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.
.....
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.
.130-17
Mass
air
flow
sensor
(hotwire),testing
and
replacing
.
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.
.....
.
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.
.
.
.
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
Page 148 of 759
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
.
Page 149 of 759
FUEL
INJECTION
130-
3
Fuel
metering
.
The
ECM
meters
fuel
bychanging
the
The
engine
management
system
compensates
automatical-
opening
time
(pulsewidth)
of
the
fuel
injectors
.
To
ensure
that
ly
for
changes
in
the
engine
due
to
age,
minor
wear
or
small
injector
pulsewídth
is
the
only
factor
that
determines
fuel
me-
problems,
such
as
a
disconnected
vacuum
hose
.
Asa
result,
tering,fuel
pressure
is
maintained
bya
fuel
pressure
regula-
idle
speed
and
mixture
do
not
need
lo
be
adjustedas
partof
tor
.
The
injectors
are
mounted
lo
a
common
fuel
supply
called
routine
maintenance
.
the
fuel
rail
.
The
ECM
monitors
engine
speed
to
determine
the
duration
NOTE-
ofinjector
openings
.
Other
signals
to
the
ECM
help
determine
Poordriveabilitymaybe
encountered
when
the
batteryis
injector
pulse
time
for
different
operating
conditions
.
A
tem-
disconnected
and
reconnected
.
when
the
battery
is
dis-
connected,
the
adaptive
memory
is
lost
The
system
will
perature
sensor
signals
engine
temperature
for
mixture
adap-
readaptafterabout
ten
minutes
of
drfving
.
tion
.
A
throttle
position
sensor
signals
throttle
position
.
The
exhaust
oxygen
sensor(s)
signal
information
about
combus-
tion
efficiency
for
control
of
the
air-fuel
mixture
.
1992
to
1995
DISA
(Dual
Resonance
Intake
System)
engines
are
equipped
with
a
single
sensor
.
1996
and
later
(OBD
II)
engines
are
equipped
with
an
oxygen
sensor
before
TheE36
4-cylinder
engine
is
equipped
with
a
dual
intake
andone
after
each
catalytic
converter
.
Forexample,the
M52
runner
system,
termed
DISA
.
DISA
offers
the
advantages
of
engine
is
equipped
withfour
oxygen
sensors
.
both
short
and
long
intake
pipes
.
Long
intake
runners
are
most
useful
at
low
to
medium
engine
rpm
for
producing
good
Idle
speed
control
.
ldle
speed
is
electronically
controlled
torque
characteristics
.
Short
intake
runners
produce
hígherviathe
idle
speed
control
valve,
which
maintains
idle
speed
by
horsepower
at
hígher
engine
speeds
.
bypassing
varying
amounts
of
air
around
theclosed
throttle
valve
.
Idle
speed
is
not
adjustable
.
NOTE-
Knock
(detonation)
control
.
Knock
sensors
monitor
and
The
term
DISA
comes
from
the
German
words
Differen-
control
ignition
knock
through
the
ECM
.
The
knock
sensors
zierte
Sauganlage,
and
can
roughlybe
translated
as
"dif-
fering
intake
manifold
configuration
."
See
100
Engine-
function
like
microphones
and
are
able
to
convert
mechanical
General
foradditional
information
on
DISA
operation
.
vibration
(knock)
into
electrical
signals
.
The
ECM
is
pro-
grammed
to
react
to
frequencies
that
are
characteristic
of
en-
Manifold
construction
:
The
intake
manifold
is
a
two-piece
gine
knock
and
adapt
the
ignition
timing
point
accordingly
.
metal
construction,
with
a
pair
of
runners
in
thetop
section
See120
Ignition
System
for
further
details
.
and
four
runners
in
the
lower
section
.
A
butterfly
valve
is
in-
stalled
in
the
lower
section,
enabling
the
DISA
solenoid
toiso-
NOTE-
late
one
pair
of
runners
from
the
other
pair
.
See
Fig
.
2
.
The
1992
M50
engine
is
not
equipped
with
knock
sen-
Operation
.
With
the
DISA
butterfly
valve
closed,
the
pipes
sors
.
All
other
engines
are
equipped
with
two
knock
in
thetop
half
of
the
manifold
act
together
with
the
ram
air
sensors
.
pipes
in
the
lower
halfto
producea
single,
long
air
intake
pipe
for
each
cylinder
.
See
Fig
.
3
.
The
column
of
aír
oscíllating
in
Basic
Engine
Settings
this
combined
pipe
significantly
increases
engine
torque
in
the
medium
rpm
range
.
Idle
speed,
idle
mixture
(%CO),
and
ignition
timing
arenot
adjustable
.
The
adaptive
engine
management
system
is
de-
signed
to
automatically
compensate
for
changes
in
engine
op-
eratingconditions,
although
the
adaptive
range
is
limited
.
Once
these
limits
are
exceeded,
driveability
problems
usually
be-
come
noticeable
.
Above
approximately
4,800
rpm,
the
butterfly
valve
between
the
intake
air
pipes
for
the
two
cylinder
groups
is
opened
.
The
shorter
pipes
in
the
lower
manifold
section
now
become
the
main
suppliers
of
ram
air
to
the
cylinders,yielding
greater
pow-
er
at
the
upper
end
of
the
engine
rpm
range
.
See
Fig
.
4
.
Control
components
.
The
DISA
butterfly
valve
is
actuated
NOTE-
electro-pneumatically
via
the
engine
control
module
(ECM)
.
lf
the
system
adaptive
limits
are
exceeded,
the
Check
The
valve
begins
to
open
as
engine
speed
rises
aboye
4,840
Engine
light
will
most
likely
come
on,
indicating
an
rpmand
closes
below
4,760
rpm
.
The
action
of
the
valve
is
de-
emissions-
related
fault
For
Check
Engine
light
diag-
liberately
delayed
to
prevent
it
from
opening
and
closing
repeat-
nostics,
see100
Engine-General
.
edly
within
a
short
time
.
GENERAL
Page 160 of 759
130-
1
4
FUEL
INJECTION
NOTE-
Be
sure
to
retrieve
thrust
washer
behind
fuel
pressure
regulator
on
6-cylinder
engine
.
4
.
Installation
is
reverse
of
removal
.
Replace
O-rings
.
Fuel
pressure
regulator,
replacing
(under
car
mount)
WARNING
-
Fuel
will
be
discharged
.
Do
not
disconnect
any
wires
that
could
cause
electrical
sparks
.
Do
not
smoke
or
work
near
heaters
or
other
fire
hazards
.
Keep
an
approved
tire
extinguisher
handy
.
On
late
4-
and
6-cylinder
cars,
the
fuel
pressure
regulator
is
mounted
beneath
the
left
sideof
the
car,
under
a
protective
cover
.
See
Fig
.
20
.
0012726
Fig
.
20
.
Fuel
pressure
regulatorlocation
underneath
car
(arrow)
.
Vac-
uum
hose
to
regulator
is
shown
at
A
.
(Protective
cover
has
been
removed
.)
5
.
Installation
is
reverse
of
removal
.
Replace
O-rings
.
BOSCH
DME
Ml
.
7
COMPONENT
TESTS
AND
REPAIRS
BOSCH
DME
Ml
.7
COMPONENT
TESTS
AND
REPAIRS
CA
UTION-
Use
only
a
digital
multimeter
when
testing
compo-
nents
and
wiring
.
Use
of
an
analog
VOM
may
damage
the
engine
control
module
.
4-cylinder
cars
with
M42
engines(1992
to
1995)use
the
Bosch
DME
M1
.7
fuel
injection
system
.
Electrical
tests
of
the
main
and
fuel
pump
relays
and
the
DME
engine
control
module
(ECM)
are
covered
earlier
in
this
section
.
Fuel
pump
tests
arecovered
in
160
Fuel
Tank
and
Fuel
Pump
.
Air
flow
sensor,
testing
and
replacing
DME
M1
.7
fuel
injection
uses
a
volume
air
flow
type
sensor
with
integrated
intake
air
temperature
(IAT)
sensor
.
The
sen-
sor
provides
a
varyingvoltage
signal
to
the
ECM
based
on
the
position
of
the
air
vane
.
As
the
vane
doorswings
open
thepo-
tentiometer
increases
the
voltage
signal
to
the
ECM
.
The
IATsensor
adapts
theoutput
signal
to
the
ECM
based
on
intake
air
temperature
.
1
.
Check
ECM
reference
voltage
to
sensor
:
"
Peel
back
rubber
boot
from
air
flow
sensor
harness
connector
.
"
Turn
ignition
keyon
.
"
Check
for
5
volts
between
terminal
1
of
harness
con-
nector
and
ground
.
See
Fig
.
21
.
"
Turn
ignition
key
off
.
"
If
voltage
is
not
present
or
incorrect,
check
wring
from
ECM
and
check
air
flow
sensor
reference
voltage
out-
put
at
ECM
.
See
Table
h
.
1
.
Working
under
car
below
driver's
seat,
remove
protec-
tive
cover
from
below
fuel
pressure
regulator
.
"
Remove
intake
air
bootfrom
sensor
.
2
.
Remove
vacuum
hosefrom
fuel
pressure
regulator
.
"
Connect
a
digital
multimeter
(ohms)
across
terminais
1
and
2
.
Swing
air
flow
sensor
vane
through
its
travel
3
.
Remove
locking
clip
retaining
fuel
pressure
regulator
.
range
.
Resistance
should
change
steadily
without
in-
terruption
.
4
.
Wrap
a
shop
rag
around
regulator,
then
remove
regula-
"
If
any
faults
are
found,
the
air
flow
sensor
is
faulty
and
tor
from
213
way
valve
by
pullingstraight
out
.
should
be
replaced
.
2
.
Check
air
flow
sensor
potentiometer
:
3
.
Check
IAT
sensor
resistance
:
"
With
harness
connector
disconnected
at
air
flow
sen-
sor,
check
resistance
across
sensor
terminais
4
and
5
of
air
flow
sensor
.
Compare
tests
results
to
values
in
Table
d
given
later
.
If
any
faults
are
found,
the
air
flow
sensor
should
be
replaced
.
Page 163 of 759
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
Page 168 of 759
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
.
Page 169 of 759
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
Page 174 of 759
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