1998 BMW M3 sensor

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

Pin



~
Signal



1
Componentffunction



1
signal

FUEL
INJECTION



130-
33

45



ground



Ignition
circuit
shield



Ground
shieldfor
ignition
circuit
monitoring

46



output



Fuel
consumption
(KVA
signal)



To
instrument
cluster

47



output



Crankshaft
rpm



Engine
speed
(TD)
signal
to
instrument
cluster

48



output



A/C
compressor
control



A/C
compressor
relay
terminal
85
49
vacant
-



-

50



output



Ignition
coil
control,
cyl
.
1



Primary
signal,
ignition
coil
1

51



output



Ignition
coil
control,
cyl
.
2



Primary
signal,
ignition
coil
2

52



output



Ignition
coil
control,
cyl
.
3



Primary
signal,
ignition
coil
3

53
vacant
-



-

54



input



Power
supply



Battery
voltagefrom
main
relay
(terminal
87a)

55



ground



Ground



Ground
for
ignition
control

56



input



Power
supply
(terminal15)



Batteryvoltage
with
key
on
or
engine
running

57



input



Ignition
timing
intervention



From
A/T
control
module
58
vacant
-



-

59



output



Throttleposition
sensor
(TPS)



Voltage
supply
to
TPS
(5
VDC)

60



input



Programming
voltage



Data
link
connector

61
vacant
-



-

62
vacant
-



-

63
vacant
-



-

64



input



A/C
on
signal



From
integrated
climate
control
module
65



input



A/C
pressure
signal



From
integrated
climate
control
module
via
A/C
pressure
switch

66



input



On-board
computer



Drive-away
protection
enable
(starter
immobilization
relay)

67
vacant
-



-

68
vacant
-



-

69



input



Knock
sensor
#2
(cyl
.
4,5,
6)



Knock
sensor
#2
signal

70



input



Knock
sensor
#1
(cyl
.
1,2,
3)



Knock
sensor
#1
signal

71



ground



Ground



Ground
for
knock
sensors
and
shields

72
vacant
-



-

73



input



Throttleposition
sensor
(TPS)



Throttleposition
signal

74
vacant
-

75
vacant
-



-

76
vacant
-

77



input



Intakeair
temperatura



Intakeair
temperatura
sensor
(0-5
VDC)

78



input



Engine
coolant
temperature



Engine
coolant
temperature
sensor
(0-5
VDC)

79
vacant
-

80
vacant
-



-

81



input



Automatic
transmission
gear
positionlneutral



A/T
parkor
neutral
position
signal
safetyswitch

82
vacant
-



-

83
vacant
-



-

84
vacant
-



-

85
vacant
-



-

86
vacant
-



-

87



input



Diagnostic
connector
(RxD)



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

88



input/output



Diagnostic
connector
(TxD)



Diagnostic
TxD
(transmit)
signal
to
pin
20
in
Data
link
connector

ECM
PIN
ASSIGNMENTS

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

130-
3
6



FUEL
INJECTION

Pin



1
Signal



1
Componentffunction



1
Signal

1



output



Ignition
coil
control,
cyl
.
2



Primary
signal,
ignition
coil
2

2



output



Ignition
coil
control,
cyl
.
4



Primary
signal,
ignitioncoil
4

3



output



Ignition
coil
control,
cyl
.
6



Primary
signal,
ignition
coil
6
4
ground
Ground



Ground

5



output



Fuel
injectorcontrol,
cyl
.
2



Pulsed
ground
(injection
pulse
width
in
ms)
cyl
.
2
6



output



Fuel
injectorcontrol,
cyl
.
1



Pulsed
ground
(injection
pulse
width
in
ms)
cyl
.
1

7



output



Mass
air
flow
meter



Mass
air
meter
signal

8



input



Mass
air
flow
meter



Mass
air
meter
signal

9



output



Instrument
cluster



Fuel
consumption
signal

10



output



Engine
coolant
temperature
(ECT)
sensor



ECT
signal

11



output



Fueltankpressure
sensor



Fueltankpressure
sensor
control

12



input



Throttleposition
sensor
(TPS)



Throttleposition
signal

13
-

14



input



Intake
air
temperature
(IAT)
sensor



Intake
air
temperature
signal

15



Traction
control



AST
module

16



input



Automatic
climate
control



Automatic
climate
control

17

18



input



Electronic
immobilizer
control
(EWS
II)



Electronic
immobilizer
control
(EWS
II)
module

19



Automatic
climate
control



Automatic
climate
control

20



-



Instrument
cluster



Instrument
cluster

21



output



Camshaft
actuator
(VANOS
solenoid)
control



Camshaft
actuator
(VANOS
solenoid),
switched
ground

22



output



Fuel
injectorcontrol,
cyl
.
3



Pulsed
ground
(injection
pulse
width
in
ms)
cyl
.
3

23



Fuel
injectorcontrol,
cyl
.
6



Pulsed
ground
(injection
pulse
width
in
ms)
cyl
.
6

24



Fuel
injectorcontrol,
cyl
.
4



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

25



output



Oxygen
sensor
heater
control



Oxygen
sensor
heater
ground

26



input



Power
supply
(terminal
30)



Battery
voltage(B+)
at
all
times

27



output



Idle
speed
control
valve



Pulsed
ground-open
signal
(see
also
pin
53)

28
ground
Ground



Ground
29



output



Ignition
coil
control,
cyl
.
1



Primary
signal,
ignition
coíl
1

30



output



Ignition
coil
control,
cyl
.
3



Primary
signal,
ignition
coil
3

31



output



Ignition
coil
control,
cyl
.
5



Primary
signal,
ignition
coil
5

32
ground
Ground



Ground
33



output



Fuel
injector
control,
cyl
.
5



Pulsedground
(injection
pulsewidth
in
ms)
cyl
.
5

34
ground
Ground



Ground
35



output



Secondary
air
injection



Secondary
air
injection
pump
relay
control

36



output



Engine
speed
output



Engine
speed
signal

37
-

38



ground



Knock
sensor



Shielding
for
knock
sensors

39



output



Intake
air
temperature
sensor
(IAT
Sensor)



Voltagesupply
to
IAT
sensor
and
ECT
sensorEngine
coolant
temperature
(ECT)
sensor

40



output



Crankshaft
position
sensor
(Hall
effect)



Crankshaft
position
sensor
control

41



ground



Camshaft
position
(CMP)
sensor



Shielding
for
CMP
sensor

42



output



Throttle
position
sensor
(TPS)



TPS
ground

43



input



Camshaft
position/rpm
sensor



Camshaft
position/rpm
sensor
control

44



output



Throttle
position
sensor
(TPS)



Voltagesupply
to
TPS
(5
VDC)

45



Traction
control



AST
module
46



-



Instrument
cluster



Instrument
cluster

ECM
PIN
ASSIGNMENTS

Table
I.
ECM
Pin
Assignment-Siemens
DME
MS
41
.1

Table
I
.
ECM
Pin
Assignment-Siemens
DME
MS
41
.1
(continued)

Pin



I
Signal



I
Component/function



1
Signal

FUEL
INJECTION



130-
37

47
-

48



input



Crankshaft
position
sensor
(Hall
effect)



Crankshaft
position
sensor
control

49



input



Power
supply
(terminal
15)



Batteryvoltage
with
key
onor
engine
running
50



output



Solenoid
valve
(running
losses)



Running
losses

51



output



Carbon
canister
valve



Carbon
canister
valve
control

52vacant
-

53



output



Idle
speed
control
valve



Pulsed
ground-close
signal
(seealsopin29)
54



input



Power
supply



Battery
voltagefrom
main
relay
(terminal
87)

55
vacant
-

56
-

57



input



Knock
sensor
(cyl
.
1-3)



Knock
sensor
input
Signal

58



output



Knock
sensor
(cyl
.
1-3)



Knock
sensor
control

59



input



Knock
sensor
(cyl
.
4-6)



Knock
sensor
input
Signal

60



input/output



Diagnostic
connector
(TxD)



Diagnostic
TxD
(transmit)
signal
to
pin
18
in
Data
link
connector
61



output



Oxygen
sensor
heater
(monitoring
sensor)



Oxygen
sensor
heater
ground

62



output



Secondary
air
injection



Secondary
air
injection
control
valve

63



output



Knock
sensor
(cyl
.
4-6)



Knock
sensor
control

64



input



Camshaft
position/rpm
sensor



Camshaft
position/rpm
sensor
control

65



input



Camshaft
position/rpm
sensor



Camshaft
position/rpm
sensor
control

66
-

67



output



Oxygen
sensor



Oxygen
sensor
reference
voltage

68



output



Evaporative
purge
valve
control



Pulsed
ground
with
engine
at
normal
temperature
and
varyingengine
load

69



output



Fuel
pump
relay
control



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

70
vacant
-



-

71



output



Oxygen
sensor
heater
(regulating
sensor)



Oxygen
sensor
heater
ground

72



output



Oxygen
sensor
(monitoring
sensor)



Oxygen
sensor
referencevoltage

73



input



Main
relay
control



Main
relay
activation
(terminal
85)

74



output



A/C
compressor
control



A/C
compressor
relay
control

75



input



Oxygen
sensor



Oxygen
sensor
signal

76



not
used



-



-

77



input



Oxygen
sensor
(regulating
sensor)



Oxygen
sensor
signal

78



input



Oxygen
sensor
(monitoring
sensor)



Oxygen
sensor
signal

79



output



Oxygen
sensor
(regulating
sensor)



Oxygen
sensor
referencevoltage

80



Traction
control



AST
module

81



Traction
control



AST
module
82



Traction
control



AST
module
83



output



Crankshaft
position
sensor
(Hall
effect)



Crankshaft
position
sensor
control

84
vacant
-



-

85



output



Automatic
transmission



Automatic
transmission
control
module

86



input



Automatic
transmission



Automatic
transmissíon
control
module

87



input



Power
supply



Battery
voltage
from
main
relay
(terminal
87)

88



input/output



Diagnostic
connector
(TxD)



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

ECM
PIN
ASSIGNMENTS

160-2



FUEL
TANK
AND
FUEL
PUMP

0011943
1
.
Filler
pipe



10
.
Fuel
compensating
siphon
pump
and
hose
assembly
2
.
Filler
pipe
grounding
tab



(models
built
from
1/95)
3
.
Vent
pipe



11
.
Fueltank
4
.
Threaded
collar



12
.
Tank
support
strap
5
.
Rubber
ring
seal



13
.
Bolt-tighten
to
23
Nm
(17
ft-Ib)
6
.
Fuel
pump



14
.
Fuel
expansion
tank
7
.
Left
side
fuel
leve¡
sender(models
built
from
1/95)



15
.
Fuel
tank
pressure
sensor
(OBD
II)
8
.
Right
side
fuel
leve¡
sender9
.
Left
side
fuel
leve¡
sender
with
fuel
compensating
siphon
pump
(models
built
up
to
1/95)

Fig
.
1
.



E36
fuel
tank
assembly
.

FUEL
TANK
AND
LINES



Fuel
tank,
draining

The
plastic
fuel
tank
is
mounted
beneath
the
center
of
the
car
(beneath
rear
seat)
.
Mounted
in
the
fuel
tank
are
the
fuel
pump
and
fuel
leve¡
sending
units
.
Connecting
lines
for
the
evaporative
emission
control
systemand
expansion
tank
are
also
attached
to
the
tank
.
When
performing
the
procedures
that
follow,
refer
toFig
.
1
.

Fuel
tank
capacity
for
E36
modeis

"All
ex
.
1996
M3
(3
.0
L)
.....
.
..
..
65
liters
(17
.0
gal)

"
1996
M3
(3.0L)
modeis
.
...
.
..
.
.62
liters
(16
.4
gal)

FUEL
TA
NKAND
LINES

The
fuel
tank
should
be
drained
into
an
approved
storage
unit
or
another
car's
fuel
tank
.

WARNING
-
"
Before
removing
the
tank,
be
sure
that
afl
hot
components
such
as
the
exhaust
system,
are
completely
cooled
down
.

"
Fuel
may
be
spilled
.
Do
not
smoke
or
worknear
heaters
or
other
Pire
hazards
.

1
.
Disconnect
negative
(-)
cable
from
battery
.

CAUTION-

Prior
to
disconnectiog
the
battery,
read
the
battery
disconnection
cautions
given
at
the
front
of
this
manual
on
paga
vi¡¡
.

170
Radiator
and
Cooling
System

GENERAL
.
.
.....
.
...
.
.
.
.
.
....
.
.
.
.
.
.
.
.170-1

Coolant
Pump
and
Thermostat
........
.
.
.
.
170-1

Radiator
and
Expansion
Tank
.........
.
...
170-1

Cooling
Fans
.
....
.
.
.
.
.
.
.
.
.
.....
.
......
170-2

Warnings
and
Cautions
.
.
.
.
.
.
.
.
.
.
.
.
...
.
.
.
170-2

TROUBLESHOOTING
...
.
.
.
...
.
.
.
.
.
.
.
.
.170-2

Cooling
System
Pressure
Test
...
.
.
.
.
.
.
.
.
.
170-3

Thermostat
Quick
Check
.
.
.
.
...
.
.
.
.
.
.
.
.
.
170-3

Temperature
Gauge
Quick
Check
.
.
.
.
.
.
.
.
.
170-3

Cooling
fan,
testing
.
.
.
.
........
.
.
.
.
.
.
.
.
.
170-4

COOLING
SYSTEM
SERVICE
.
.
.
.
.
.
.
.
.
.
170-5

Coolant,draining
and
filling
.
.
......
.
.
.
.
.
..
170-5

Cooling
system,
bleeding

(radiator
with
integral
expansion
tank)
.....
170-6

GENERAL

This
section
covers
repair
and
troubleshooting
information
for
the
engine
cooling
system
.
For
heater
core
and
related
heating
and
air
conditioning
components,
see640
Heating
and
Air
Conditioning
.

Coolant
Pump
and
Thermostat

A
centrifuga¡-type
coolant
pump
is
mounted
to
the
front
of

the
engíne
.
The
belt-driven
pump
circulates
coolant
through

the
system
whenever
the
engíne
is
running
.
A
thermostat
con-

trols
the
flow
of
coolant
into
the
radiator
.

When
the
engíne
is
cold
the
thermostat
is
closed
so
coolant

bypasses
the
radiator,
recirculating
from
the
engíne
directly

back
to
the
pump
.
When
the
engíne
reaches
operating
tem-

perature,
the
thermostat
opens
and
coolant
circulates
through

the
whole
system
including
the
radiator
.

Radiator
and
Expansion
Tank

The
radiator
is
a
crossflow
design
.
A
translucent
expansion

tank
provides
for
coolant
expansion
at
higher
temperatures
and

easy
monitoringof
the
coolant
leve¡
.

On
4-cylinder
modeis,
the
radiator
expansion
tank
is
integral

with
the
radiator
.
See
Fig
.
1
.

RADIATOR
AND
COOLING
SYSTEM



170-1

Belt-driven
cooling
fan,
replacing
.
.......
.
.
.
170-7

Electric
cooling
fan,
replacing
.
.
.
.....
.
.
.
.
.
170-8

Auxiliary
cooling
fan,
replacing
.
.
.....
.
.
.
.
.
170-8

Thermostat,
replacing
.
.
.
.
.
.
.
.
.
.....
.
.
.
.
.
170-9
Coolant
pump,
replacing
..........
.
.
.
.
.
.
170-10

RADIATOR
SERVICE
.....
.
......
.
.
.
.
.
.
170-11

Radiator,
removing
and
installing
....
.
.
.
.
.
.
170-11

TABLES

a
.
Coolant
Temperature
Sensor
Wire
Colors
...
.
..
.
.
170-3b
.
Auxiliary
Cooling
Fan
Switching
Temperatures
.:.
.170-4
c
.
Auxiliary
Cooling
Fan
Temperature
Switch
Tests
..
..
.
...
...
.
.............
.
..
.
.
170-5d
.
Cooling
System
Capacities
..............
..
.
.
.
170-6

A
.
Expansion
tank



C
.
Dualtemperature
fan
switch
B
.
Radiator
drain
screw

Fig
.
1
.
Radiator
assembly
with
integral
expansion
tank
(4-cylinder
engine)
.

On
6-cylinder
models,
a
standalone
expansion
tank
is
used
.

On
cars
with
automatic
transmission,
ATF
is
circulated
through
an
additional
heat
exchanger
(ATF
cooler)
.

GENERAL

Cooling
System
Pressure
Test



If
the
engine
overheats
and
no
other
cooling
system
testsindicate
trouble,
the
radiator
may
have
some
pluggedpassag-

A
cooling
system
pressure
test
is
used
to
check
for
internal



es
that
are
restricting
coolant
flow
.

leaks
.
Some
of
the
common
sources
ofinternal
leaks
are
a
faulty
cylinder
head
gasket,
a
cracked
cylinder
head,
or
a



Temperature
Gauge
Quick
Check
cracked
cylinder
block
.

The
coolant
temperature
sensor
is
located
on
the
intake
To
doa
cooling
system
pressure
test,
a
special
pressure



manifold
(left)
side
of
the
cylinder
head,
under
the
intake
man-
tester
is
needed
.



ifold
runners
.
See
Fig
.
2
.

WARNING
-

At
normal
operating
temperature
-
the
cooling
sys-
tem
is
pressurized
.
Allow
the
system
to
cool
before
opening
.
Release
the
cap
slowly
to
allow
sale
re-
tease
of
pressure
.

With
the
engine
cold,instan
a
pressure
tester
to
the
expan-

sion
tank
.
Pressurize
thesystem
to
the
specification
listed
be-

low
.
Pressure
should
not
drop
more
than
0
.1
bar
(1
.45
psi)
for

at
leakt
two
minutes
.
If
the
pressure
drops
rapidly
and
there
is
no
sign
of
an
externa¡
leak,
the
cylinder
head
gasket
may
be
faulty
.
Considera
compression
test
as
described
in
100
En-

gine-General
.

The
screw-on
type
expansion
tank
cap
should
also
be
test-

ed
using
a
pressure
tester
and
the
correct
adapter
.

Cooling
System
Test
Pressure

"
Radiator
test
pressure
.........
.
1
.5
bar
(21
.75
psi)

"
Radiator
cap
test
pressure
..
.
........
2
bar
(29
psi)

CA
UTION-

Exceeding
the
speclfied
test
pressure
could
dam-
age
the
radiatoror
other
system
components
.

Carefully
inspect
the
radiator
cap
for
damage
.
Replace
a

faulty
cap
or
a
damaged
cap
gasket
.

Thermostat
Quick
Check



In
later
models,
the
ECT
sensor
and
the
gauge
sender
are
combined
into
one
sender
unit
.
For
wire
colors
refer
to
Table
a
.
To
check
if
the
thermostat
is
opening
and
coolant
is
circulat-

ing
through
the
radiator,
allow
a
cold
engine
to
reach
operat-

ing
temperature
(temperature
gauge
needieapproximately

centered)
.
Shut
off
engine
.
Feel
the
top
radiator
hose
.
If
the

hose
is
hot
to
the
touch,
the
coolant
is
probably
circulating
cor-
rectly
.
If
there
are
any
cool
areas
in
the
hose
or
radiator,
cool-

ant
flow
to
the
radiator
is
probably
restricted
.
Check
for
a
faulty

thermostat
or
aplugged
radiator
.

NOTE-

A
thermostat
that
is
stuck
open
will
cause
the
engine
to
warmup
slowly
and
run
belownormal
temperature
at
highway
speed
.
A
thermostat
that
is
stuck
closed
will
re-

strict
coolant
flow
to
the
radiator
and
cause
overheating
.

RADIATOR
AND
COOLING
SYSTEM



170-
3

U
.¡ig
.v

Fig
.
2
.
Temperature
gauge
sender
on
M44
engine
.
Temperature
gauge
sender
location
is
similar
on
al]
engines
.

In
early
models,
the
engine
coolant
temperature
(ECT)
sen-

sor
for
the
fuel
injection
and
the
coolant
temperature
gauge

sender
are
located
side
by
side
.

Table
a
.
Coolant
Temperature
Sensor
Wire
Colors

Function



Sensor



Terminal



Wire
colors
location
number

Two
sensors
:
Temperature
Rear
1
Brown/violet
gauge
sender



2



Brown/yellow
ECT
sensor



Front



1



Brown/red
2



Brown
or
Brown/black

One
sensor
:
Temperature
Dual
1
Brown/yellow
gauge
sender



sensor



2



Brown/violet
ECT
sensor



3



Brown/red
4
Brown/black
or
Grey/black

TROUBLESHOOTING