MITSUBISHI GALANT 1989 Service Repair Manual

33B-42
ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting
IO] FRONT-HEIGHT SENSOR CIRCUIT
.ever
Seysor
,..e
Relationship between N (normal vehicle height) and othervehicle-height levels
High 1
Normal 50
(1.97)
40(1.57)
30(1.18)
201.791
10C.39)
0
tEH (highest)._--
HH (higher than HIGH)
H (HIGH vehicle height)
NH (higher
than NORM)
N (NORMAL vehicle height)
EL (lowest) A-27
[Unit: mm
(in.11
Front-helghf
sensor
Operation
The front-height sensor detects (by detecting the
sistors, and the slits in the disc thus interrupt, or let
relative position of the body and the front axle) the
action movements (bouncing, nose diving, etc.), pass, the light beams between the light-emitting
diodes and the photo-transistors. By employing the data gathered in this way, the
sen-
sor can detect the vehicle height as any one of the
nine level classifications.
and the vehicle height, of the front of the vehicle,
The rotating disc plate rotates in the area between
four pairs of light-emitting diodes and photo-tran-
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ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting 33B-43
Diagnostic
When a signal (error code) indicating an abnormal
condition (resulting from damage or disconnection
of the heavy-line circuit, or a malfunction of a photo-transistor, etc.) is input, the alarm light
illu-
minates and control is as described in the table
below.
Diagnostic No. Attitude control Damping force
Vehicle-height
~Switch acceptance
control control
HIGHSPORT 1AUTOSOFT
22
Control stopj Held at MEDIUM Control stop Not accept
Service data indication
Code No lndrcation
Indication example
22Current vehicle-height level (ERRORWhen 22:N1111when there is a malfunction)
normallndrcates
the ON or OFF status of lndtcates
the vehicle-height-Status of each photo-interruptor
level. 1: ON,O: OFF
each
photointerruptor.If mal-22; ERRORfunction
0010
Indicates that an error code isL Status of each photo-interruptor
beina output.l:ON.O:OFF
ECU terminal voltages (when connector is connected) Termrnal
NoCondition
Terminalvoltaae
25
54,5556.57Power source for sensor
Front vehicle-herght signal
When the ECU is activated
5V
When the photo-rnterruptors are ON
o
v
When the photo-interruptors are OFF
5V
1 36/ Sensor circuit ground I ConstantlvIo
v
I
Checking the front-height sensor circuit (with the connector disconnect\
ed)
Terminal
Connectron
destination cNomeasured part
:zFront-height sensor
power-supply crrcuit
22
56
57
Front-height sensor
Resistance
brMeasurement
Resistance 25-36Tester connection
54-36
55-36
56-36
57-36
t
Troubleshooting hints (mechanical malfunctions) Check condition
Standard
Contact the tester’s
(-1 probe to Contrnuity
terminal 25, and the ( + ) probe to(Theterminal 36.
rndrcator
Note fluctuates)
Even if the result is good here,
the sensor must not be judged
tcbe certainly good.
Contact the tester’s
(-1 probe to
terminal 25, and the (+ 1 probe to
terminal 36, and check to be sure
that there is continuity, leave the
connections as they are.
Connect the tester’s
(-1 probe to
each terminal of the wiring
harness connector, and the
(+ Jprobe to terminal 36
Separate the lever (of the height
sensor) from the rod, and slowly
nave the lever up and down.
No Continurty
IContinuity
Malfunction mode Malfunction probable cause
Malfunction
Note
Improper Because of the improper adjustment of the
-adjustment of the
front-height sensorfront-height sensor rod, a signal not
l When the engine is stopped and left as it is,
corresponding to the actual vehicle height is the height of onlythe front end decreases to
rodbeing sent to the ECU lower than the NORMAL vehicle height
l With the engrne running, the height of the front
end IS lower than the NORMAL vehicle
height
l With the engine running (AUTO mode and NORMALvehicle

hetght). the height of the front
end becomes higher than the NORMAL helght)
1 TSB RevisionI

33B-44 ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting
[ll] REAR-HEIGHT SENSOR CIRCUIT
1989 models
F-18
-1
F-l 9
pjimlq
piTgs%q
c-07
D-27
G-05
High
I
Normal50 (1.97)
4..:::.:.:_~-.^::::::::“.“::i
+E
jr;::::::::::_:
40 (1.57)
30 (1.18)
LowI[Unit: mm (in.11
ECU
1 Rear vehicle-height/fisjnmy3tp I (I
Rear-height sensor12AQ414
-LL (lower than LOW) HH (higher than HIGH)
H (HIGH vehicle height)
NH (higher than NORM)
N (NORMAL vehicle height)
NL (lower than NORM)
L (LOW vehicle height)
12AO182
Operation
The rear-height sensor detects (by detecting the relative position of the body and the rear axle) the
action movements (bouncing, pitching, etc.), and
the vehicle height, of the rear of the vehicle. The
rotating disc plate rotates in the area between three
pairs of light-emitting diodes and photo-transistors, and the slits in the disc thus interrupt, or let pass.
the light beams between the light-emitting diodes
and the photo-transistors. By employing the datagathered in this way, the sensor can detect the vehi-
cle height as any one of the seven level
classifica-
tions.
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ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshootina 33B-45
Diagnostic
When a signal (error code) indicating an abnormal condition (resulting from damage or disconnection
of the heavy-line circuit, or a malfunction of a photo-transistor, etc.) is input, the alarm light
illu-
minates and control is as described in the table
below.
Diagnostic No. Attitude control
23Control stop
Service data indication Damping force
control
Held at MEDIUM Vehicle-heigh
t
Switch acceptance
control
HIGH SPORT AUTOSOFT
Control stop
Not accept
Code No Indication
Indication example
23 Current vehicle-height level (ERROR When 23;N
1111when there is a malfunction)
normal
Indicates the ON or OFF status of Indicates the vehicle-height
levelL Status of each photo-interruptor
each photo-interruptor. 1: ON, 0. OFF
If mal-23; ERROR0010
function Indicates that an error code IS
being output.L Status of each photointerruptor1: ON, 0. OFF
ECU terminal voltages (when connector is connected) Terminal
No.Signal Condition
25 Power source for sensor
When the ECU is activated
61.62
63,64Front vehicle-height sIgnalWhen the photo-mterruptors are ON
When the photo-interruptors are OFF
36 Sensor circuit ground
Constantly Terminal
voltage
5v
o
v
5V
o

v
Checking the rear-height sensor circuit (with the connector disconnecte\
d)
rTerminal Connection destination or

M
easurement
No measured part Tester connection
Check conditionStandardRear-herght
sensor
power-supply circuit Resistance
25-36 Contact the tester’s (-) probe to
Continuity
terminal 25. and the
(+) probe to(Theterminal 36 indrcator
Note fluctuates)
Even if the result is good here,
the sensor must not be judged to be certainly good.
61
Es
Rear-height sensor A Resrstance
61-36No
F
Contact the tester’s (-)
probe to
62-36 terminal 25, and the ( +) probe toContinuity
63-36 terminal 36, and check to be sureIthat there is continuity; leave the Continuity
connections as they are.
Connect the tester’s
(-1 probe to
each termrnal
of the wiring
harness connector, and the
( +)probe to terminal 36. Separate the lever (of the height
sensor) from the rod, and slowly
move the lever up and down
64
- _. .
DResistance64-groundConstantly Continuity
1 roubleshooting hints (mechanical malfunctions)
Malfunctionmode Malfunction probable cause
MalfunctionNote
Improper Because of the improper adjustment of the l When the engine is stopped and left as it IS,
-adjustment of the
rear-height sensorrear-height sensor rod, a signal not
the height of only the rear end decreases to
rod correspondrng
to the actual vehicle height IS berng
sent to the ECU lower than the NORMAL vehicle height.lWith the engrne running, the height of the rear
end is lower than the NORMAL vehicle height
lWith the engine
running (AUTO mode and
NORMAL vehicle herght). the height of the rear
end becomes higher than the NORMAL height).
TSB Revision

33B-46 ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting
1121 VEHICLE-SPEED SENSOR CIRCUIT
1BAOOSl
r__----1IElectronic
I controlledII!i%& ECU ,
8V
I
I
~:!~
1L- ----

-
J
ECU
I
F-l 9
C-Oi
9
;
11M
6
Meter
assembly
C-52
12AO416
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ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting 33B-47
Operation
The vehicle-speed sensor is a reed switch type with pulse signals being \
sent four times for each rotation of
the transaxle output gear.
Diagnostic
If there is damage or disconnection of the heavy-line
the alarm light illuminates and control is as
de-
circuit, or a malfunction of the vehicle-speed sensor, scribed in the table below.
Diagnostic No. 24
Attitude control Damping force
Vehicle-height Switch acceptance
control controlHIGHSPORTAUTO SOFT
Control stop
Held at MEDIUMHeld at NORMAL
Not accept
Service data indication Code No lndrcation
Display
24 Indicates the vehicle speed Input
to
24: SPEED SNSR. 0 km/h
the ECU (including the simulated
vehicle speed)
ECU terminal voltages (when connector is connected)
ITerNmo_na’ConditionTerminal
voltage
I I
58 /
I
Vehicle-speed signal1 When the vehicle-speed sensor reed switch is ONo
v
IIII
*When the vehicle-speed sensor reed switch is OFF8V
TSB Revision
*In order to supply the EPS pull-up power
(8V)
Checking the vehicle-speed sensor circuit (with the connector disconnec\
ted)
Termrnal
Connectron
destination or M
easurement
No measured part
Tester connection
Check conditionStandard
58 Vehrcle-speed
sensor
Resistance
58-groundWith the battery’s (-1 termrnal
Continuity
disconnected, move the vehicleIback and forth.Nocontinuity
Troubleshooting hints In actual urban driving, it is not so likely that the
sensor fails.., ^_^.tnrottle IS kept 3U% or more open for more than 30
seconds. Therefore, the conditions have been This takes into account that the vehicle speed sen-
somewhat stricter to prevent unnecessary applica-
sor is shared by many systems such as EPS,
Auto-
tion of the fall safe function due to the racing of the cruise control, etc. and that the failure of the sensor
engine when stopped. However, the vehicle may can also be detected from the state of these sys-
terns.run uncontrolled for some distance when the speed

33B-48 ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting
[13] REAR-PRESSURE SENSOR CIRCUI
12AC371
Rear-pressure sensor output voltage characteristic
5IAfl
F-27
F-l 8
-1
24 b
23
9
zia2
%,
45'III0400500
6 7(57)(71)Kz;(I?$ f?lt) f%, :l?!!
Rear air springs internal pressure kPa (psi)12AO460
Rear-pressuresensorI
8
t
25
ECU
VAc-
il
Sensor power
1source 5 V
12*02*1
Operation
The rear-pressure sensor detects the internal pressure of to a predetermined “map”, the supplying and exhaust
the rear air springs. times are corrected as necessary, according to data from
Although the timing of air supply and exhaust for control this sensor, in order to cope with changes of the load
of the vehicle attitude is basically determined according carried by the
vehicle and other factors.TSB Revision

ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting 33B-49
Diagnostic
If, because of damage or disconnection of the heavy-line below. Note, however, this diagnostic signal is given if
circuit, or a malfunction of the rear-pressure sensor, etc., there is an overload.
a htgher than normal value of the internal pressure of the
l :1989 models
air springs is indicated continuously, the alarm light The alarm light does not illuminate for 1990, 1991,
illuminates*, and control is as described in the table 1992, 1993 models.
I1
Damping forceVehicle-heightSwitch acceptanceDiagnostic No.Attitude controlcontrol
control
HIGH 1 SPORT 1 AUTO 1 SOFT
25Control stopNormal
Only the vehicle-height
increase Not Accept
operation control function stops. accept
I
1990, 1991, 1992, HIGH-AUTO change possible. If the above diagnostic num\
ber is detected, the damping force that is
1993 models:the base of the SOFT mode and AUTO mode changes to the MEDIUM damping fo\
rce.
Service data indication
1 Code No. 1Indication
Standard valueDisplay
25Rear-pressure sensor output Fluctuates within a range of 0.5V
to 4.5V
25; RR. PRESS. SNSR. 2.45V
voltage when the body is shaken from side to side.
Condition
Reference value
Front seats: 2 persons When HIGH vehicle height
When NORMAL vehicle height
When LOW vehicle
height
1.6OV
0.9ov 0.86V
ECU terminal voltages (when connector is connected) ConditionTerminal
voltage
25Power supply for sensor
37Rear air spring pressure signal When the ECU is activated
Low rear air spring pressure
High rear air spring pressure
5v
0.5vI
4.5v
When wiring IS damaged or disconnected5v
35 Sensor circuit ground
Constantly o
v
Checking the rear-pressure sensor (with the connector disconnected)
Terminal Connection destination or MeasurementNomeasured part
Tester connection
Check condition
Standard
ERear-pressure sensorResistance
25-35 Constantly Approx.
All resistances 5 kll
37Rear-pressure sensor
Resistance
37-35 Change should be smooth (accordingO-5 klloutput to the air pressure applied to the rear
-pressure sensor) within the standard
value range shown at the right
Troubleshooting hints (mechanical malfunctions) Malfunctionmode Malfunction probable cause
Malfunction
Note
Harness
short-circuit Because of a short-circurt
of the harness, etc , Insufficient control of the attitude, resulting in a
-no correction of the air-supply and exhaust time feeling of incompatibility
can be made to compensate for a loaded
condition of the vehicle. Air leakage
Wear, damage, etc. of the O-ring
Vehicle height decreases if not corrected-
TSB Revision

33B-50 ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting
1141 STOP LIGHT SWITCH CIRCUIT
Battew
I
P
I
C-36I
7 1 4*15A / JbJ;;ion
c-47
To stoplights F-l 6
1-1
183It
Target vehicle height order of priorityJ I
12A0495
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ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting 33B-51
Operation
When the brake pedal is depressed, the stop light
switch is switched ON and
1% is sent to the ECU,
thus resulting in the detection that braking is in progress.
Service data indication
Code No. Indication
Display
I 26 I
Indicates the ON or OFF status of26; STOP LAMP SW.
the stop light switch.ON/OFFI
ECU terminal voltages (when connector is connected)
Terminal Signal ConditionTerminal
No voltage
83 Stop light switch signal
When the stop light switch is ON o
v
When the stop light switch is OFF
B+
B+: Battery positive voltage
Checking the stop light switch circuit (with the connector disconnected\
) Terminal Connection destination or
MeasurementNo measured part Tester connection
Check condition
Standard
83 Stop light switch Voltage
83-groundIgnitionDepress the brake
switch ON pedal.B+
Do not depress the
o
v
brake pedal.
B+: Battery positive voltage
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-,