MITSUBISHI GALANT 1989 Service Repair Manual

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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33B-54 ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting
[17] DAMPING FORCE SWITCHING ACTUATOR DRIVE CIRCtJI’
ECU
*
F-17A-62
F-05F-10
jtTIff&@f&q
<Front. L.H.) (Front, R.H.) (Rear, R.H.)
Y
Actuator
J
17I
tll
F-06
t ttt
a-I 2
d
AJL7-*UC 1
m .T
(Rear, L.H.)/
12A0454
1 TSB
Revision

ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting 33B-55
Operation
The damping force switching actuator is the step motor. That allows the control rod of each shock at one of four levels (HARD, MEDIUM, AUTO-SOFT
or SOFT).
absorber to rotate, thus selecting the damping force
Diagnostic
If there is damage or disconnection of the heavy-line
circuit, the alarm light illuminates, and control is as
described in the table below. (Because the
ac-
tuators are connected in parallel, there can be no detection if wiring damage or disconnection occurs
at the final circuit.)
Diagnostic No.Attitude control
41Control stop
Actuator compulsory activation
Damplng forcecontrol
Control stop Vehicle-height
control
Held at NORMALHIGH
Switch acceptance
SPORT AUTO
Not accept
SOFT
Code No.Applrcable operatron Descriptron
of activation
01SOFT damplng force The damplng force is compulsorily swltched to SOFT: there is a return to theonginal damping force three seconds thereafter
02AUTO-SOFT damping force The damping force is compulsorily switched to AUTO-SOFT; there is a return to
the onginal damping force three seconds thereafter
03 MEDIUM damping force The damping force is compulsorily switched to MEDIUM; there is a return \
to the
onginal damping force three seconds thereafter
04 HARD
damplng force The damping force IS compulsorily switched to HARD; there IS a return to theonginal damping force three seconds thereafter
ECU terminal voltages (when connector is connected) Terminal
No
Slgnal
Condition Terminal
voltage
1Damping force swrtchlng
actuatoractlvatlon signal When the damping force switching actuator IS stopped6V
Phase AO=B+2p When the damping force switching actuator is activated
Damping force switching actuator
activation signal
Phase
BWhen wiring is damaged or dlsconnectedB+
6 Damplng
force switchrng
actuatoractivation slgnal
When the damping force switching actuator IS stopped 6V
Phase C
7p When the damping force switching actuator is activated
Damping force switching actuatorB+ = 0 pulse
activation signal
Phase DWhen wiring is damaged or disconnected o
v
B+: Battery positive voltage
Checking the damping force switching actuator drive circuit (with the c\
onnector disconnected)
TSB Revision
Terminal Connection
destination or MeasurementNomeasured part
Tester connection
Check condltlonStandard1
ADamping force switching Resistance 1-6
Four coils that have a constant
actuator (step motor)Approx
resistance of 6.4 i-O.1 ohms are 1611
connected in parallel (front and rear)
2Damping force swltchlng Resistance 2-7
Four coils that have a constant7actuator (step motor) Approx.
resistance of 6.4 t 0.1 ohms are1.612connected in parallel (front and rear).

33B-56 ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting
[18] COMPRESSOR DRIVE CIRCUITExhaust valve for vehicle-height
12A0261 BatteWr=-
r
d
ii
\
Compressor relay----
-d-i==1
a
-ISub@ 40A fusiblelink
-1
@ 15A
A-39
compres-sor relay
A-1 2
Ccmcms-scar
IPhfdlf”nctmdetectm
ECU
A-06X
fEJs&nodvalve powersource relay
F-l?
F-16
12AO484
I fl /is*oo4s~
1 TSB Revision

ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting 33B-57
Operation
The compressor is activated when the pressure
within the high-pressure tank decreases to 760
kPa
(108 psi) or lower, and then stops two seconds after
the pressure reaches 950
kPa (135 psi). Note,
however, that the compressor is not activated while
Diagnostic If there is damage or disconnection of the heavy-line
circuit, or a short-circuit, or a malfunction of the
output transistor within the ECU, the alarm light illuminates and control is as described in the table the return pump is operating. A thermal switch is
provided at the motor circuit. This thermal switch
functions to interrupt the power to the motor (in
order to protect the compressor) if the temperature
within the compressor becomes high.
below.
(Note that the diagnostic is only applicable up to the
compressor relay.)
Diagnostic No.
43
Attitude control
Control stop Damping force
control
Held at MEDIUM Vehicle-height
control
Control stopHIGH
Switch acceptance
SPORT AUTOSOFT
Not accept
Actuator compulsory activation
1 CodeNo. /Applicable operationIDescription of activationI
05Compressor relay ON The compressor relay is compulsorily switched ON for a period of three s\
econds.
ECU terminal voltages (when connector is connected)
TerminalNo.Signal ConditionTerminal
voltage
23Compressor relay actrvatron
signal When the compressor relay is ONB+
When the compressor relay is OFF o
v
During fail-safe ov
(solenoid valve power-source relay switch OFF) ---
TSB Revision
Checking the compressor drive circuit (with the connector disconnected)\
B+: Battery positive voltage
Terminal Connection destination or
MeasurementNo.measured part Tester connection
Check conditionStandard
~~
Compressor relay Resistance52-ground
Troubleshooting hints (mechanical malfunctions)
Malfunction
mode Malfunction probable cause
Malfunction
Note
The compressor relay is fused. The compressor relay contacts are shorted.
The compressor won’t stop, causing the battery
-to discharge.
The compressor is The compressor won’t operate due to shorting, The vehicle height can’t be increased.
-
stuck.
etc.

33B-58 ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting
[19] RETURN PUMP DRIVE CIRCUITReturn pump relay
-
Battery
“

2
m
A
(.(B)
m
A
xlReserve tank assembly
12A0262
JI1
ECU
F-17
F-1812AOuw
Operation
The return pump is activated when the pressure within the low-pressure pressure tank increases to 140
kPa (20 psi) or higher, and then stops two
seconds after the pressure is reduced to 70
kPa (10
psi) or lower. A thermal switch is provided at the motor circuit.
This thermal switch functions to interrupt the power
to the motor (in order to protect the return pump) if
the temperature within the return pump becomes
high.1TSB Revision

ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting 33B-59
Diagnostic
If there is damage or disconnection of the heavy-line illuminates and ‘control is as described in the table
circuit, or a short-circuit, or a malfunction of the
out-
put transistor within the ECU, the alarm ligh
t
below. (Note that the diagnostic is only applicable
up to the compressor relay.)
II/6
Diagnostic No.Attitude controlDamping forcecontrol Vehicle-height
control Switch acceptanceHIGH1 SPORT jAUTO) SOF
T
I44
Rolling control only
Held at
stops. MEDIUMRolling control only stoos.
Not accept
Actuator compulsory activation
CodeNo ’Applicable operation Descnption
of activation
06Return pump relay ON
The return pump relay is compulsorily switched ON for a period of three \
seconds.
ECU terminal voltages (when connector is connected) Terminalvoltage
I
3
2
Return pump relay activation signal
When the return pump relay is ON
B+
When the return pump relay is OFF o
v
During fail-safe ov
(solenoid valve power source relay switch OFF)
Checking the return pump drive circuit (with the connector disconnected\
)
B+: Battery positive voltage Connectron

destrnation or Measurementmeasured part Tester connectron
Check condrtronStandard
32Return pump relay
Resistance32-groundConstatly Approx 750INext apply battery voltage to
terminal 32. Return pump
operation
NOTE (Refer to Vol.2 GENERAL for the circuit diagram.)
Procedures for changing the internal pressure of the low-pressure tank
(1) For 70 kPa (IO psi) or lower
Short-circuit the battery power-source @ terminal to the return pump relay @ terminal in order to activate the return
pump for a few seconds, and then leave as is.
(2) For 140 kPa (20 psi) or higher
Short-circuit the battery power-source @ terminal to the front intake-air solenoid @I terminal and the front right
solenoid @I terminal in order to connect the high-pressure tank and low-pressure ta\
nk, and then leave as is for a few
seconds.
Procedures for changing the internal pressure of the high-pressure tank
(I) For 760 kPa (108 psi) or lower
Short-circuit the battery power-source @I terminal to the discharge-air solenoid (for vehicle-height adjustment)\
@Iterminal, the front intake-air solenoid @I terminal and the front right solenoid @ terminal and the front discharge-air
solenoid @I terminal in order to release the atmosphere inside the high-pressure ta\
nk, and then leave as is for a few
seconds.
(2) For 950 kPa (135 psi) or higher
Short-circuit the battery power-source @ terminal to the compressor relay @ terminal in order to activate the
compressor for a few seconds, and then leave as is.
Troubleshooting hints (mechanical malfunctions)
Malfunctionmode Malfunction probable cause
Malfunction
Note
1
The return pumpThe return pump relay contacts are shorted.
relay is fused The return pump won’t stop, causing the
battery to discharge.
The return pump is The return pump won’t operate due to short-
* Insufficient attitude-control effect.
-
stuck.ing.
etc. l
Vehicle height increases after rolling control.
TSB Revision

33B-60 ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting
[20] EXHAUST VALVE ACTIVATION CIRCUIT (FOR VEHICLE-HEIGHT ADJUSTMENT)Exhaust valve
[for vehicle-height
adjustment)
Usually OFF; ON
vehicle-height
downward Air cleaner
0lOOA Main fusible
4-J link
R&Vbox
F-17
l!!!b
Malfunctm*e*ectwn
ctrcwt
A-l 1
2
8 (
1;
*-1mm =
Exhaust valve
for
vehicle-heightadjustment >
12A0251
*: 1991 models1312AO498
TSB Revision

ACTIVE-ELECTRONIC CONTROL SUSPENSION - Troubleshooting 33B-61
Operation
The exhaust valve for adjustment of the vehicle height is installed at the compressor assembly.
This valve is switched ON only when a downward
Diagnostic
If there is damage or disconnection of the heavy-line
circuit, or a short-circuit, or a malfunction of the out-
put transistor within the ECU, the alarm light adjustment of the vehicle height is being made; it
functions to discharge air (from the air springs) into
the atmosphere.
illuminates and control is as described in the table
below.
Diagnostic No.
45
Attitude control
Rolling control
only stops Damping force
control
Held at
MEDIUM Vehicle-height
control
Rolling control
only stops. Switch acceptanceHIGHSPORT
AUTO
SOFT
Not accept
Actuator compulsory activation
The exhaust valve for vehicle-height adjustment is activated by the following.
Code No Applicable operation
07 Vehicle height
downward adjustment
ECU terminal voltages (when connector is connected)
TerminalNo. SignalCondition Terminal
voltage
31Exhaust valve (for vehicle-height
adjustment) activation srgnalWhen the exhaust valve (for vehicle-height adjustment) is ON (open)
When the exhaust valve (for vehicle-height adjustment)
is OFF
(closed)
B+
o
v
During fail-safe (for solenoid valve power source relay
swatcho
v
OFF)
B+: Battery positive voltage
Checking the exhaust valve (for vehicle-height adjustment) activation \
circuit (with the connector discon-
nected)
Termtnal

Connectlon destination or MeasurementCheck condition Standard
No measured part Tester connection
31Exhaust valve (for
Resistance31 -groundConstantly Approx.
vehicle-height1511adjustment)
Troubleshooting hints (mechanical malfunctions)
Malfunction mode Malfunction probable cause
Malfunction
Note
Stuck in the OFF
Arr cannot be discharged because the valve is Vehicle height doesn’t decrease.Diagnostic
(closed) position stuck in the OFF (closed) due to corrosion, trouble code
freezing, etc. caused by moisture penetration.
No.54 is output.
Stuck
rn the ON
(open) positlonAir discharge cannot be stopped because the l Vehicle height doesn’t increase.Diagnostic
valve is stuck in the ON (open) due to corrosion, l Compressor doesn’t stop.trouble codefreezlna.
etc. caused bv moisture penetration.No.55 is output.
Arr leakage at valve
Valve seat IS worn.
seat l Vehicle herght
doesn’t increase.
l Compressor doesn’t stoo.Diagnostic troublecode No.55 is output
1 TSB Revision