1991 MITSUBISHI 3000GT service

33B-1
ELECTRONIC
CONTROL
SUSPENSION
CONTENTSM33AA-B
CIRCUIT DIAGRAM
22SPECIAL TOOLS........................................................................3
................................................................
DAMPING FORCE CHANGEOVERSPECIFICATIONS....................................................................2
ACTUATOR................................................................................20General Specifications.......................................................2
ECS CONTROL UNIT................................................................21Service Specifications.......................................................3
ECS INDICATOR LIGHT............................................................20STEERING ANGULAR VELOCITYa .
ECS SWITCH............................................................................
19
G SENSOR................................................................................
19
POSITION DETECTION SWITCH............................................20
SERVICE ADJUSTMENT PROCEDURES
............................
12
On-Vehicle Inspection........................................................12
SENSOR*....................................................................................-IY
STOP LIGHT SWITCH............................................................20
THROTTLE POSITION SENSOR
............................................20
TROUBLESHOOTING............................................................4
VEHICLE SPEED SENSOR....................................................
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
(I)A Supplemental Restraint System (SRS), which uses a driver-side air bag, has been installed in the 3000GT.(2)The SRS includes the following components: impact sensors, SRS diagnosis unit: SRS warning light, aiir bagmodule, clock spring, interconnecting wiring.Other SRS-related components (that may have 1:o be
removed/installed in connection with SRS service or maintenance) are indicated in the table of contents byan asterisk (*).
WARNING!(1)Improper service or maintenance of any component of the SRS, or any SRS-related component, can lead to
personal injury or death to service personnel (from inadvertent firing of the air bag) or to the driver (from
rendering the SRS inoperative).
(2) Service or maintenance of any SRS component or SRS-related component must be performed only at an
authorized MITSUBISHI dealer.(3) MITSUBISHI dealer personnel must thoroughly review this manual, and especially its GROUP
Ei2B -Supplemental Restraint System (SRS), before beginning any service or maintenance of any component of theSRS or any SRS-related component.

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ELECTRONIC CONTROL SUSPENSION (ECS) - Specifications33B-3
Items
Shock absorber
Type
Max. lengthmm (in.)
Min. lengthmm (in.)
Strokemm (in.)
Damping force at 0.3 m/seeI.9 ft.)/sec.N (Ibs
Expansion
Hard
Medium
Soft
Contraction
Hard
Medium
Soft
Stabilizer bar
Mounting method
Outside dia.
mm (in.)FWD
IAWDI
Hydraulic, cylindrical double-acting type
515(20.3)610(24.0)
356(14.0)407(16.0)
159
(6.3)203(8.0)
1,800(397)
1,200(265)
550(121)
950(209)
850(187)
850(143)
10 (.37)
Pillow ball type
M33CB-B~SERVICE SPECIFICATIONS
Rear suspension1'FWDItemsFront suspension
Standard value
Camber0” + 30’0”
k 30’- O”10’ Ik 30’
Caster3”55’ t 30’
Toe-inmm(in.)0+3(0f.12).522.5(.02+.I).5k2.5
SPECIAL TOOLS
ToolNumber
MB991 341
Name
Multi-use tester
sub-assembly
MB991 359ROM packM33DA-B
Use
Inspection of electronic control suspension
system
l Reading and erasing self-diagnosis codesl Reading service datal Actuator testTSB Revision

33B-6ELECTRONIC CONTROL SUSPENSION (ECS) - Troubleshooting
I I2When diagnosis code No. 21 is output, or when anti-roil control only stops.
Using MUT, check service data onthe steering angular velocity sensor.Check by entering simulated vehicle speed tosimulate anti-roll controls. (Refer to P.33B-16.)
+No
No. 2,3 and 4 terminal voltages up
to specification?Standard: 5 V
Yes
>Is continuity provided across the followingareas?Between steering angular velocity sensorand ECS control unit
Between No. 2 terminal and No.!Between No. 3 terminal and No.
Between No. 4 terminal and No.
Yes
Is trouble cleared by replacing
End
1 TSB RevisionI

ELECTRONIC CONTROL SUSPENSION (ECS) - Troubleshooting33B-7
3When diagnosis code No. 24 is output
1 i
Using MUT, check service data onvehicle speed sensor. Good?
YesjCheck by entering simulated vehicle speed from MUT
late high speed-sensitive control. (Refer to P.338-17.)
NoYesNo
151//Disconnect vehicle speed sensor con-nectar and check harness connector.j Good) /Replace ECS control unit.1
No. 1 terminal voltage and continuity
between No. 2 terminal and ground
up to specification?
(Sensor power supply and ground)Standards:No. 1 terminalBattery voltage
No. 2 terminalContinuity provided
Correct harness (between No. 1 terminal of vehicle
speed sensor and battery and between No. 2 terminal
of vehicle speed sensor and ground).
l-.-l
Yes
JI Nni1Is continuity provided between No. 3
terminal of vehicle speed sensor and
No. 53 terminal of ECS control unit?Correct harness.
1
Yes
Check vehicle speed sensor. (Refer
to P.33B-19.) Good?
No-Replace vehicle speed sensor.
Yes
IReplace ECS control unit.I
Using MUT, check service data onvehicle speed sensor.
No
late high speed-sensitive control. (Refer to P.33B-17.) Good!
Replace ECS control unit.
4t NoI1Is continuity provided between No.109 terminal of combination meter andNo. 53 terminal of ECS control unit?Correct harness.
Yes
Is continuity provided between No.
64 terminal of combination meter
and ground?
No
4
Correct harness.
Yes
Check vehicle speed sensor. (Refer
to P.33B-19.) Good?--+Replace vehicle speed sensor.
Yes
IReplace ECS control unit.I .
TSB Revision

33B-10 ELECTRONIC CONTROL SUSPENSION (ECS) - Troubleshooting
6Anti-dive control only stops.
Yes
Using MUT, check service data on
stop light switch. Good?>Check by entering simulated vehicle speed from MUT to
simulate anti-dive control. (Refer to P.33B-16.) Good?
,I
ch
Disconnect stop light switch con-
nector and check harness connector.f
(Between No. 2 terminal of stop light switch and battery)
Check stop light switch. (Refer to
P.33B-20.) Good?
Yes
”
Replace ECS control unit.Replace stop light switch.TSB Revision

ELECTRONIC CONTROL SUSPENSION (ECS) - Troubleshooting 33B-11
I I7
Anti-squat control only stops.III
L,
I
Using MUT, check service data onthrottle position sensor. Good?
Yes
rCheck by entering simulated vehicle speed from MUT to
simulate anti-squat control. (Refer to P.33B-16.) Good?!
1 Good1 ) Replace ECS control unit. 1
I
1I II
NoDoes check engine light illuminate?>Is continuity provided between No. 2 terminal of throttleposition sensor and No. 59 terminal of ECS controlunityII
Yes
i
Correct harness.
1Check throttle position sensor. (Refer to P.33B-20.) Good?III1
connector and check harness con-nector with ignition switch at ON.
No. 1 terminal voltage and continuityNo
Is
between No. 4 terminal and groundcontinuity provided across the following areas?
up to specification? (Sensor powerthrottle position sensor and engine control unit
No. 1 and 61 terminals
supply and ground)
No. 4 and 72 terminalsStandards:
INo. 1 terminal5 V
YesNo. 4 terminal
Continuity provided
Yes-1 1 Correct harnei:
”
Replace throttle position sensor.TSB Revision

33B-12ELECTRONIC CONTROL SUSPENSION (EC9 - i?:~~u:‘?s*men*
12FOOOESERVICE ADJUSTMENT PROCEDURES
I
ON-VEHICLE INSPECTIONIM33FHAD1. WARNING INDICATION BY ECS INDICATOR LIGHT
If a problem associated with the following items occurs, theECS indicator light (Tour Sport) in the combination light
flashes at intervals of 0.5 sec. At the same time, the
self-diagnosis code associated with the problem is outputto the diagnosis connector.
Warning Indication Items
l G sensor
l Steering angular velocity sensor
l Vehicle speed sensor
lDamping force changeover actuator (including position
detection switch)
2. SELF-DIAGNOSIS OUTPUT CHECK
(I) Check the self-diagnosis code.
(2) After the defective portion has been repaired, erase theself-diagnosis code. (If the defective portion is not
completely repaired, it may be impossible to erase the’self-diagnosis code by the MUT.)d
(3) Perform self-diagnosis output check again and checkthat the self-diagnosis code is good.

(1) Set the ignition switch to OFF.
(2) Connect the positive (+) terminal of the voltmeter to
the No. 3 terminal of the diagnosis connector beside the
junction block and connect the negative (--) terminal ofthe voltmeter to the No. 12 terminal.
(3) Set the ignition switch to ON.
(4) Read the self-diagnosis code on the basis of the
deflection of the pointer of the voltmeter.
(5) Based on the self-diagnosis code, repair the associated
defective portion.(6) Set the ignition switch to OFF.
(7) Disconnect the battery cables from the battery termi-
nals and reconnect them more than
10 seconds
thereafter.(8) Set the ignition switch to ON, perform self-diagnosis
check again, and check that the self-diagnosis code is
good.
TSB Revision

Service AdjustmentELECTRONIC CONTROL SUSPENSION (ECS) - Procedures33B-13Fail Safe and Diagnosis List
Output Code
Diagnosis Item
Fail SafeCode No.Indication Pattern
0[Good]
[Good]
l-l
11G sensor defective*l Ride controls (pinching and bouncingcontrol, bad road detection control) sl:op.
21Steering angularvelocity sensor open-circuited*
l Anti-roll control stops.
24Vehicle speed sensor*nn open-crrcurtedl Steering stability controls (anti-roll, high
speed sensitive controls) and attitude
controls (anti-dive, anti-squat) stop.l Shock absorber damping force fixed MEDIUM
F. L. damping forcefl-~-~-j 11c$i;z;;Fr actuator
R. R. damping force
I /
64 j-jMJ-~-~-~ ~t$ec~Z$rn&ftYrrZ& /
NOTE(1)Control stop, warning indication and fixed damping force return to normal when the ignition switch is set to OFF.
When any of the problems marked* occurs, if no subsequent problem occurs (for example, when the problem IStransient) normal operation will be restored even if the ignition switch is not set to OFF.(2)Even if control stop warning indication and fixed damping force return to normal as described above, the
self-diagnosis code’is stored in the memory in the ECS control unrt.
(3)The self-diagnosis code can be force-cleared by use of the MUT or by stopping the power supply to the ECS controlunit. In addition
it is automatically cleared if the ON/OFF control of the ignition swatch is repeated 60 times after the
self-diagnosis code has been output, provided that no new self-diagnosis code is output during the period.TSB Revision