1989 MITSUBISHI GALANT Service Repair Manual

33B-30 ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting
[51 HIGH-PRESSURE SWITCH CIRCUITShield plate
/v (right)
/Lo&pressure switch
High-pressure
switch
High-pressure
switch
o~~---~---~~-~l
760 (108)950 (135)
Pressure kPa (psi)
72AO172
FCI I
I-Detection ofhigh-pressuretank pressure
1
/\
0m
A-ln
6 A-38
High-pressure
switch12 A0493
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ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting 33B-31
Operation
The high-pressure switch is switched ON and OFF by the pressure in the high-pressure tank, and as a
result the ECU functions to control the activation
and stop of the compressor.
When the pressure in the high-pressure tank be-
comes 760
kPa (108 psi) or lower, the high-pressure
switch is switched ON, and as a result the ECU
sends the drive signal to the compressor. Conversely, when the pressure of the high-pressure
tank becomes 950
kPa (135 psi) or higher, the
high-pressure switch is switched OFF, and the
compressor is stopped two seconds thereafter.
Note, however, that the compressor is not ac-
tivated, even if the high-pressure switch is switched ON, if the return pump is in operation. Note also
that there is no diagnostic function for the
high-pressure switch.
Service data indication Code No
lndlcationDisDlav
15Indicates the ON/OFF status of the
high-pressure switch. 15: HIGH PRESS. SW. ON/OFF
I
ECU terminal voltages (with connector connected)
Terminal
No.Signal ConditionTermina
l
voltaaeI
59
High-pressure tank pressure signal
When high-pressure switch is ON (low pressure)
o
v
When high-pressure switch is OFF (high pressure)
5v
Checking the high-pressure switch circuit (with the connector disconnec\
ted)
Terminal Connection destination or
M
easurement
Nomeasured part Tester connection ,
Check conditionStandard
59High-pressure
switch Reststance
59-36
High-pressure tank internal
pressure 760 kPa (108 psi) orlower Continuity
High-pressure tank internalpressure 950 kPa (135 psi) orhigher
Nocontinurty
Troubleshooting hints
Malfunctlonmode
Malfunction probable cause
MalfunctionNote
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Harness
wlrlngdamage ordlsconnectlon
Harness wiring damage or disconnection, or
Improper switch contact Compressor doesn’t operate.-
Harnessshort-crrcuit
Air leakage. Harness short-circuit, or switch short-circuit, O-ring
worn or damaged. Compressor operates without stopplng.DiagnosticNo.55output.
Rolling control feehng
of Incompatibility. very-freauent oaeration of compressor.

33B-32 ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting
[6] ACTIVE-ECS POWER SOURCE CIRCUIT
Relay box
‘
Solenoid :valve .
A-06X
*‘:
b OFF
J Iv! 1
EyllAy 1 Junction block
4‘B
IF-17
j$----hJ _____ 15---~4&L---v----.6
iI
1234
5
m67891F-18
b
;
/ b i-i
Valve actwation3m,nute* OFFcontrol circuitA^,^., .i”..%*
ECU
Sfabdization WwWL guse circuit---------JI
L---
T
122042lSolenoid valve power source
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ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting 33B-33
Operation
When the ignition is switched ON, the ECS power relay is also switched ON, and power is supplied to
the system. At the same time, the ECU switches
ON the solenoid
valve power relay, and power is
supplied to the solenoid valve activation circuit. As a
result, system operation is possible.
Diagnostic
When problems such as damage or disconnection of the heavy-line circuit, or fusing of the contacts of
the solenoid valve power relay, etc. occur, the alarm When the ignition switch is switched OFF after driv-
ing, the three-minute OFF delay timer makes
vehicle-height adjustment (down only) possible for a period of three minutes, thus preventing the vehicle
height from increasing while passengers get out of
the vehicle, etc.
light illuminates, and control is as described in the
table below.
Diagnostic No. 42 Attitude control
Rolling control
onlv stoos.
Damping force
Vehicle-height Switch acceptance
control control
/ HIGHSPORTAUTOSOFT
Held at MEDIUM
Rolling control
Not acceptonlv stoos
Service data indication
CodeNo /Indication Display
16Indicates ON/OFF status of the
iqnition switch. 16: IGNITION SW. ON/OFF
ECU terminal voltage (when connector is connected)
valve power relay output
26
Solenoid valve power relay drivesignalWhen solenoid valve power relay is ON
When solenoid valve power relay is OFFB+
B+: Battery positive voltage
Checking the ACTIVE-ECS power source circuit (with the connector discon\
nected)
Terminal Connection destination or Measurement ’No.measured part Tester connection
Check condition
5Ignition switchi Voltage5-groundIgnition switch OFF
Ignition switch
OFF-O
N
8Solenoid valve power
Voltage8-groundTerminal 26 open.
relay
Terminal 26 groundedStandard
o
v
O+B+
ov
O-B+
10ECU back-up power
sourcei Voltage1 O-ground
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B+: Batten/ positive voltage

33B-34 ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting
[7] ACTIVE-ECS indicators circuit
Battery
Column switch
-------
c n-21
f
ACTIVE-ECS 1indicator
I
(From 1990 models)
ECUII
F-17
Power source,circuif
/
EEzQ15~JgJ 1 ,2-LR
i181lllumlnatlon lightSPOK
1 1c
1’
I’
II
I 1
II
I IiI’
I I
/I
I’I 1
NOTEI-
* mark is applicable for 1991, 1992, 1993 models.ECUI TSB Revision

ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting 33B-35
Service data indication
Code No Indication
Standard value
17ECU input voltage indications when When switches are openSPORT, AUTO, SOFT, HIGH5V
switches are pressed.When SPORT switch
is ONOV
When AUTO switch is ON1.53v
When SOFT switch is ON 2.71V
When HIGH swrtch
is ON 4.02V
ACTIVE-ECS indicators check chart
1.Checking the power source circuit
Disconnect the battery terminals, and, after erasure of the
ECU mode memory, turn the ignition key to the ON position.
1
Indication example
17: MANUAL CNG. SW
4.03v
The sound of the damplng force switching actuators (steplNoThe ACTIVE-ECS power relay doesn’t function
motors), installed at the front struts and at the rear shock
--+l Disconnected or damaged wiring of the fusible link, the
absorbers, will be heard. fuse and/or the harness between the battery and the AC-TIVE-ECS power relay contacts
Yes
When terminal 15 of the ACTIVE-ECS indicator is grounded,yes
the “SOFT” damping force characteristic indicator and the -lDisconnected or damaged wiring of the ground line 15 of
“NORM” vehicle-height indicator will
illuminate.the ACTIVE-ECS indicator.
No
Approximately
12V is measured when the voltage betweenNo
ground and terminal 20 of the indicator and the ACTIVE-ECS --+l Disconnected or damaged wiring between the AC-
is measured. TIVE-ECS power relay and ECS Indicator
terminal 20.
I Yes
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-. ACTIVE-ECS Indicator power source circuit OK Proceed to
checking of the individual ACTIVE-ECS
lndlcators

33B-36 ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting
2.Checking the individual ACTIVE-ECS indicators
After disconnecting the control unit’s connector, turn the nition kev to ON
1
All items shown in the tables on the next page are satisfied~~ 8 Poor or improper contact of the ACTIVE-ECS indicator
when each terminal of the ACTIVE-ECS indicator’s connector Fand the connector terminal.is grounded and the resistance is then measured. l ACTIVE-ECS malfunction
Yes
All items shown in the tables on the next page are satisfied
when each
terminal of the wiring harness connector discon-
No
l Damaged or disconnected wiring or large contactnetted from the control unit is grounded and the resistance__*resistance, between the ACTIVE-ECS indicator and the
is then measured. connector of the control unit.
Yes
I
lPoor or improper contact of the control unit and the con-
c nectar terminal
.
0 Control unit malfunction.
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ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting 33B-37
r
ACTIVE-ECS indicator
Control unit wiring
connector terminal No harness connector
Normal
terminal No
All termrnals
are not
I
-The’SOFT” damprng
force characteristic indicator and the “NORM”
earthed vehicle-height indicator illuminate.
I
1-1 The illumination light illuminates when battery voltage is applied to t\
erminali 19.
276In addition to the “SOFT” and “NORM” indicators, the “MED\
IUM” dampingi force characteristic Indicator also illuminates.
I3/88
In addition to the “SOFT” and “NORM” indicators, the “SOF\
T”*’ switch
indicator also illuminates.
I
Ll90Connect a circuit tester and
measure the resistance when
the control mode and
vehicle-height select switches
are pressed
1 b;h is pressed.1 E;i;yi;;a 1
SOFT1 Approx. 890 fZ 1
/ HIGH1 Approx. 3090 121
577In addition to the “SOFT” and “NORM”
Indicators.
the “HIGH” switch
indicator also illuminates 6*2
-In addition to the “SOFT” and “NORM” Indicators, the alarm light
illuminates.
787In addition to the “SOFT” and “NORM” indicators, the “SOF\
T” swatch indrcator
also illuminates.
975The “NORM” vehicle-height rndicator
illumination stops, and the “HIGH”
vehicle-height indicator illuminates; the “SOFT” damping force cha\
racteristic
indicator remains illuminated.
1085The “NORM” vehicle-height Indicator illumination stops, and the “\
LOW”
vehicle-height indicator illuminates; the “SOFT” damping force cha\
racteristic indicator remains illuminated.
1178In addition to the “SOFT” and “NORM” indicators, the “AUT\
O” switchindicator also illuminates.
1380In addition to the “SOFT” and “NORM” indicators, the alarm l\
ight
illuminates.
1486 In addrtion
to the “SOFT” and “NORM” indicators, the “MEDIUM” and\
“HARD” damping force characteristic indicators also illuminate
15-The “SOFT” damping force characterrstic
indicator and the vehicle-herghtindicator illuminate.
17
1971
-
The buzzer sounds.
The “SOFT” and “NORM” indicators become slightly
dimmer when terminal
20 is connected to terminal 19
NOTE*l:1989 models
“SPORT” modeisapplicable for1990, 1991,1992,1993models
l *: Applicable to 1989 models only.
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