1989 MITSUBISHI GALANT Service Repair Manual

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
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*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-
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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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-,

33B-52
ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting
[15] BACK-UP LIGHT SWITCH CIRCUIT Ignition switch (IG,)
c-43

-T----
From 1990 models 1989
models
C-23
-1
From 1990 models Junction
block
B-21
C-23 A
fiYl%mq
1989 models
F-lfi
& 12 *
c
2 12,16
ifi
Back-up
light switch
+ From 1990
models
*
To back-up
light
ECU12AO400
Checking the back-up light switch circuit (with the connector disconnec\
ted)
Terminal Connection destination or
,v,easurement TesterNo.measured Dartconnection Check condition
Standard
72Back-up light
Voltage72-groundWith the shift leverIgnition switch OFFo
v
shifted to the REVERSE position Ignition switch ON
B+
Service data indicationB+: Battery positive voltage
Code No. Indication Display
32Indicates the ON or OFF status of
32; M/T
BACK LAMP ON/OFF
the back-up light switch.
ECU terminal voltages (when connector is connected)
TerminalNoCondition Terminal
voltage
72Manual transaxle back-up signal
I
When the back-up light switch is ON
When the back-up light switch is OFF
1
1 TSB Revision
B+
o
v
I1B+: Battery positive voltage

ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting 33B-53
1161 DOOR SWITCH CIRCUIT
L
ECU
Batten/
Dome light
ETACSunit
b +G Door light2 Door light
6? Door light
El---- g-l---
sl--
z Door light
I
Front door swatchRear door switch
Service data indication
Code NoIndication
Display
33Indicates the ON or OFF status of33: DOOR SW. ON/OFF
the door switch (Indicates ON if at least one door is opened.)
ECU terminal voltages (when connector is connected)
Condition Termrnal
voltageI
Door switch signal When a door (at least one) is opened
When the door is closed o
v
B+
Checking the door switch circuit (with the connector disconnected)B+: Battery positive voltage
ITerminal Connection destination or MeasurementNo.measured part
Tester connection
Check conditionStandardI
74Door switch
Resistance74-groundDisconnect the battery’s negative (-)
terminal and close all doors.
Disconnect the battery’s negative (-)
terminal and open the doors
one by one.Nocontinuity
Continuity
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