1998 BMW M3 coolant temp sensor
[x] Cancel search: coolant temp sensorPage 161 of 759
u0
I
.[
Ia
Fig
.
21
.
Air
flow
sensor
harness
connector
terminal
identification
.
4
.
Replacing
air
flow
sensor
:
"
Remove
large
band
clamp
attaching
air
boot
to
sensor
.
"
Remove
airfiltertop
cover,
then
remove
airflow
sensor
mounting
nuts
inside
cover
.
"
Reconnect
air
boot
and
harness
connector
.
Engine
coolant
temperature
(ECT)
sensor,
testing
and
replacing
The
engine
coolant
temperature
(ECT)
sensor
sends
con-
tinuous
engine
coolant
temperature
information
to
the
ECM
.
As
temperature
increases,
sensor
resistance
decreases
.
"
With
harness
connector
disconnected,
check
resis-
tance
across
sensor
terminals
.
"
Compare
tests
results
to
values
in
Table
d
.
FUEL
INJECTION
130-
1
5
0011984
Fig
.
22
.
M42
engine
coolant
temperature
(ECG
sensor
(arrow)
.
Table
d
.
Engine
Coolant
Temperature
Sensoror
Intake
Air
TemperatureSensor
Test
Values
(DME
1
.7)
Test
temperatures
Resistance
(k
ohms)
',
14±2°F(-10t1°C)
7-11
.6
68±2°F
(20
t
1
°C)
2
.1
-2
.9
176
±
2°F
(80
t
V
C)
0
.27-0
.40
The
ECT
sensor
is
located
under
number
one
intake
run-
'
ner
.
See
Fig
.
22
.
NOTE-
1
.
Check
ECM
referente
voltage
to
sensor
:
The
test
values
listed
represent
only
three
test
points
from
a
continuous
resistance
NTC
sensor
.
Check
the
"
Disconnect
harness
connectorfrom
ECT
sensor
.
full
linear
response
to
increasing
temperature
as
the
"
Turn
ignition
key
on
.
engine
warms
up
.
"
Check
for
5
volts
between
supply
voltage
(brown/red)
wire
of
harness
connector
and
ground
.
3
.
If
ECT
sensor
fails
these
tests,
it
is
faulty
and
should
be
"
Turn
ignition
key
off
.
replaced
.
If
no
faults
are
found,
reconnect
electrical
"
If
voltage
is
not
present
or
incorrect,
check
wring
from
harness
.
ECM
and
check
ECT
sensor
reference
voltage
output
at
ECM
.
See
Table
h
.
NOTE-
2
.
Check
ECT
sensor
resistance
:
Use
a
new
copper
sealing
washer
when
installing
sen-
sor
.
Reptace
any
lost
coolant
.
WARNING
-
Do
not
replace
the
ECT
sensor
unlessthe
engine
is
cold
.
Hot
coolant
can
scald
.
Tightening
Torque
"
ECT
sensor
to
cylinder
head
.....
..
13
Nm
(10
ft-Ib)
BOSCH
DME
M1
.7
COMPONENT
TESTS
AND
REPAIRS
Page 164 of 759
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
.
Page 165 of 759
Table
f
.
Engine
Coolant
TemperatureSensor
or
Intake
Air
TemperatureSensor
Test
Values
(DME
3
.113
.3
.1)
Test
temperatures
Resistance
(k
ohms)
14±
2°F
(-10
±
1'C)
7-11
.6
68±
2°F
(20
±
1'C)
2
.1
-2
.9
17612°F
(80
t
V
C)
0
.27-0
.40
NOTE
The
test
values
listed
represent
only
three
test
points
from
a
continuous
resistance
NTC
sensor
.
Check
the
full
linear
response
to
increasing
temperatures
as
the
engine
warms
up
.
3
.
If
ECT
sensor
fails
these
tests,
it
is
faulty
and
should
be
replaced
.
If
no
faults
are
found,
reconnect
electrical
harness
.
WARNING
-
Do
not
replace
the
ECT
sensor
unless
the
engine
is
cold
.
Hot
coolant
can
scald
.
NOTE-
Use
"
a
new
copper
sealing
washer
when
installing
sensor
.
Replace
any
lost
coolant
.
Tightening
Torque
"
Engine
coolant
temperature
sensor
to
cylinder
head
.........
..
.
..
...
13
Nm
(10
ft-lb)
Intake
air
temperature
(IAT)
sensor,
testing
and
replacing
The
intake
air
temperature
(IAT)
sensor
signal
is
usedasa
correction
factor
for
fuel
injection
and
ignition
timing
.
Thissen-
sor
is
mounted
in
the
intake
manifold
behind
the
throttle
posi-
tion
switch
.
See
Fig
.
28
.
Check
TPS
function
by
disconnecting
theharnessconnec-
1
.
Check
that
ECM
reference
voltage
is
reaching
IAT
sen-
tor
and
testing
continuity
across
the
terminalswhile
changing
sor
:
the
throttle
position
.
Resistance
test
values
are
listed
below
.
If
"
Disconnect
IAT
sensor
harness
connector
.
the
resuits
are
incorrect,
replace
the
throttle
position
sensor
.
"
Turn
ignition
keyon
.
See
Fig
.
29
.
"
Check
for
5
volts
between
supply
voltage
wire
of
har-
ness
connector
and
ground
.
NOTE-
"
Turn
ignition
key
off
.
The
throttle
position
sensor
is
not
adjustable
.
If
test
re-
sults
are
incorrect,
the
sensor
should
be
replaced
.
IAT
Sensor
Supply
Voltage
"
M50/S50US
engines
.
........
grey
wire
and
ground
FUEL
INJECTION
130-19
Fig
.
28
.
Intake
air
temperature
sensor
location
on
M50/S50US
engine
(arrow)
.
If
voltage
is
not
present
or
incorrect,
check
wiring
from
ECM
and
check
reference
voltage
signal
at
ECM
(pin
77)
.
See
Ta-
ble
i
or
Table
j
.
2
.
Check
IAT
sensor
resistance
:
"
With
harness
connector
disconnected,
check
resis-
tance
acrosssensor
terminals
.
Compare
tests
resuits
to
values
in
Table
f
given
earlier
.
"
If
IAT
sensor
fafs
thistest
it
is
faulty
and
should
be
re-
placed
.
3
.
If
no
faults
are
found,
reconnect
electrical
harness
.
Throttle
position
sensor
(TPS),
testing
and
replacing
The
throttle
position
sensor
(TPS)
is
mounted
on
the
side
of
the
throttle
housing
and
is
directly
connected
to
the
throttle
valve
shaft
.
The
ECM
sends
a
voltage
signal
to
the
potentiom-
eter-type
sensor
and
monitors
the
voltage
that
comes
back
.
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 170 of 759
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
.
Page 171 of 759
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
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
Page 175 of 759
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