1991 MITSUBISHI 3000GT Service Manual

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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-4ELECTRONIC CONTROL SUSPENSION (ECS) - TroubleshootingTROUBLESHOOTING
M33EAAE
QUICK REFERENCE CHART FOR TROUBLESHOOTING
SymptomsXS
indicator lightdoes not switch
TROUBLESHOOTING HINTS
“1. The G. sensor is a sensor associated with ride control (detecting pitching, bouncing and rough road). If itfails, therefore, ride control stops.
“2. A self diagnostic decision on the steering angular velocity sensor is made by the ECS control unit which
internally detects the voltages of the two sensor output lines connected to the ECS control unit to detectan open circuit in the signal line. When the signal line is short-circuited or when the power line is
open-circuited, however, it cannot be detected. In a situation where anti-roll control only stops, if
self-diagnosis code No. 21 is not on display, a short-circuited sensor output line or open-circuited sensorpower line is suspected.
“3. The vehicle speed sensor is a sensor associated with attitude controls (anti-dive, anti-squat) and steering
stability controls (anti-roll, high speed sensitive controls). If all these controls stop, therefore, trouble in the
sensor is suspected. The vehicle speed sensor is also in use for operation of the speedometer and for theother electronics controlled systems for the engine, automatic transaxle, etc.
“4. The sensor associated with anti-squat control is the throttle position sensor. The sensor is also used for
control of the engine and automatic transaxle. If the sensor fails, therefore, the check engine light in the
combination meter will light, and engine self-diagnosis code No. 14 will be output. In a situation whereanti-squat control only stops, therefore, if the check engine light does not light, defective wiring is
suspected between the ECS control unit and throttle position sensor.
TSB Revision

ELECTRONIC CONTROL SUSPENSION (ECS) - Troubleshooting33B-5
1When diagnosis code No. 11 is output
Disconnect G sensor connector.
No. 1 terminal voltage and continuity
between No. 3 terminal and ground
up to specification?
(Sensor power supply and ground)Standards:
No. 1 terminal5 V
No. 3 terminal
Continuity provided
IYes.-
-1Is continuity provided across the following
areas?
!
BetweenG sensor and ECS control unit
Between No. 1 terminal and No. 54
BetweenNo. 3 terminal and No. 57
,
Replace ECScontrol unit.Correct harness.
LNo
Continuity provided between No. 2) Correct harness.
terminal of G sensor and No. 61
terminal of ECS control unit?
I Yes
4N?Is trouble cleared by replaced G
sensor?bReplace ECS control unit.
I
Yes
EndTSB 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-8ELECTRONIC CONTROL SUSPENSION (ECS) - Troubleshooting
III
1 4 1 When diagnosis code Nos. 61, 62, 63 and 64 are output.
(-yesUsing MUT, check actuator. (Referto P.33B-15.) Good?
No
Remove cap at top of shock absorber
associated with diagnosis code No.,
disconnect connector directly
connected to shock absorber, and
checkharness connector with
ignition switch at ON.r
~...- NoNo. 1 and 3 terminal voltages upto specification?Standard: 5 V
YesIs continuity provided across the following areas of shock
Lsorber associated with diagnosis code No.?Between shock absorbers and ECS control unit
Between No. 1 and 7 terminals of F.R. shock absorber
Between No. 3 and 6 terminals of F.R. shock absorber
Between No. 1 and
10 terminals of F.L. shock absorber
Between No. 3 and 9 terminals of F.L. shock absorber
Between No. 1 and 13 terminals of R.R. shock absorber
Between No. 3 and 12 terminals of R.R. shock absorber
Between No. 1 and 16 terminals of R.L. shock absorber
Between No. 3 and 15 terminals of R.L. shock absorber1
YesNo
””
Is continuity provided between
rTi”’
Correct harness (between No. 2 and 4 terminals of shockabsorber and ground).No. 2 and 4 terminals and ground?
age, force-drive actuator by MUT. IsStandard: 9 V during forced drive
Yes
+Is continuity provided across the following areas of shockabsorber associated with diagnosis code No.?
shock absorbers and ECS control unit
Between No. 5 and 5 terminals of F.R. shock absorber
No. 5 and 8 terminals of F.L. shock absorber
No. 5 and 11 terminals of R.R. shock absorber
No. 5 and 14 terminals of R.L. shock absorber
I
YesNo
Is trouble corrected by replacingshock absorber (including dampingforce changeover actuator and POSI-tion detection switch) associated
Yes
1
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ELECTRONIC CONTROL SUSPENSION (ECS) - Troubleshooting:33B-9
1 5 1 ECS indicator light does not switch when ECS switch is operated.
Yes
Does ECS indicator light flash?+Read diagnosis code and check area associated with dralgnosrs.---IIIcode.
Disconnect ECS switch connector
and check harness connector with
- No
No. 10 terminal voltage and
continuity between No. 11 terminal
and ground up to specification?Standards:
No.
10 terminal
5 V
No. 11 terminal
Continuity provided
YesCorrect harness.
Check ECS switch. (Refer to P.33B-
YesReplace ECS switch.
check ECS indicator light for burntReplace ECS indicator light bulb.
Is continuity provided across the- Correct harness.
combination meter andECS control unit
No. 10 and 2 terminals
No. 11 and 3 terminals
Yes
”No
Is continuity provided between No. 2> Correct harness.
terminal of combination meter andground?
I
Yes
No
Is trouble cleared by replacingcombination meter?
-Replace ECS control unit.
IYesTSB 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