MITSUBISHI 3000GT 1991 Service Manual

AUTOMATIC TRANSAXLE - Troubleshootincl23-19Based upon use of the troubleshooting
Checks should be made of fluid levels and
the condition of the ATF, as well as the
condition of the manual control cables;
adjustments should then be made if found
to be necessary.
If a presumption has been made that there
is an abnormal condition somewhere in
the electronic-control system, check the
fault code, in order to determine the
probable location of the problem, by using
a multi-use tester or voltmeter.
I
When the abnormal system is discovered,
check each element (sensors, etc.) one by
one, and make repairs as necessary.
IWhen the abnormal condition is presumed
to be in the oil-pressure-control system
When the result of the oil-pressure test
does not satisfy the specified pressure,
check each system at places related to the
valve body, check the oil-pressure pas-
sages for leakage, etc.
I
If the problem isunusually dirty ATF,
abnormal noises, oil leakage, or slippage of
the clutch or brakes, or an abnormal
condition of the transaxle itself, disassem-
ble and repair the transaxle.
TROUBLESHOOTINGM23EEAYFunctional malfunctions of the ELC4A/T can lead to other
problems, such as those described below:(I
) Improper maintenance and/or adjustments
(2) Malfunctions of the electronic control functions
(3) Malfunctions of mechanical functions
(4) Malfunctions of hydraulic control functions
(5) Malfunctions of engine performance
etc.
In order to properly determine (“Troubleshoot”) the source of
these malfunctions, it is first essential to methodically question
the user concerning the details of the problem, such as the
condition of the problem, the situation at the time the problem
occurred, and any other relevant information, all in as much
detail as possible. The user should also be asked whether or
not the problem has occurred more than once, and under what
conditions.
Subsequently, certain tests should be conducted in a certain
order, as described at the left.
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23-20AUTOMATIC TRANSAXLE - Troubleshootina
TROUBLESHOOTING GUIDE
‘resumed cause
38Malfunction of transaxle control unttX
NOTE- @ indicates items of prlortty during Inspection.PSCV = Pressure control solenoid valveAbbrewatlons TPS = Throttle powon sensor
DCCSV = Damper clutch control solenoid valveSCSV = Shift control solenoid valveOD = Overdwe
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AUTOMATIC TRANSAXLE - Troubleshooting23-21
L
1
i
4
E
7
Ec
II
1
1:
1:
lr
l!
11
1;
12
15
2c
2'
2;
2:
21
2:
2c
2
2
2
3
3
3
3
3
3
3
3
3
i
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23-22AUTOMATIC TRANSAXLE - Troubleshooting
0”
TM362
DIAGNOSIS AND TEST
FLUID LEVEL AND CONDITION
1.Drive until the fluid temperature reaches the usual tempera-
ture
[70 - 80°C (160 - 18O”F)].2. Place vehicle on level floor.
3. Move selector lever sequentially to every position to fill
torque converter and hydraulic circuit with fluid, then place
lever in “N” Neutral position. This operation is necessary to
be sure that fluid level check is accurate.
4. Before removing dipstick, wipe all dirt from area around
dipstick. Then take out the dipstick and check the condition
of the fluid.
The transaxle should be overhauled under the following
conditions.
l If there is a “burning” odor.
l If the fluid color has become noticeably blacker.
lIf there is a noticeably great amount of metal particles in
the fluid.
5.Check to see if fluid level is in “HOT” range on dipstick. If
fluid level is low, add automatic transaxle fluid until level
reaches “HOT” range.
Low fluid level can cause a variety of conditions because it
allows pump to take in air along with fluid. Air trapped in
hydraulic circuit forms bubbles which make fluid spongy.
Therefore, pressures will be erratic.
Improper filling can also raise fluid level too high. When
transaxle has too much fluid, gears churn up foam and
cause same conditions which occur with low fluid level,
resulting in accelerated deterioration of automatic transaxle
fluid.
dIn either case, air bubbles can cause overheating, fluid
oxidation, which can interfere with normal valve, clutch, and
servo operation. Foaming can also result in fluid escaping
from transaxle vent where it may be mistaken for a leak.
6. Be sure to examine fluid on dipstick closely.
,CONTROL CABLEWhether control cable is properly adjusted can be confirmed by
checking whether inhibitor switch is performing well.
1. Apply parking brakes and service brakes securely.
2. Place selector lever to “R” range.
3. Set ignition key to “ST” position.
4. Slowly move the selector lever upward until it clicks as it
fits in notch of “P” range. If starter motor operates when
lever makes a click, “P” position is correct.
5.Then slowly move selector lever to “N” range by the same
procedure as in foregoing paragraph. If starter motor
operates when selector lever fits in
“N”, “N” position is
correct.
6. Also check to be sure the vehicle doesn’t begin to move
and the lever doesn’t stop between P-R-N-D.
7. The control cable is properly adjusted if, as described
above, the starter motor starts at both the “P” range and
the “N” range.
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AUTOMATIC TRANSAXLE - Troubleshootina23-23
p: E LC-4A/T~9: Dlagnosls control@I: Ground
:Multi-use tester>
Cigarette
lighter
socketDiagnosisconnector
MB991 359
16POl51
OBTAINING FAULT CODES(1) Connect the voltmeter or multi-use tester to the connector
for diagnosis.
(2) Read the output fault codes.
Then follow the remedy procedures according to the
“FAULT CODE DESCRIPTION” on the following page.
NOTEl As many as a maximum of ten fault codes, in the
sequence of occurrence, can be stored in the Random
Access Memory (RAM) incorporated within the control
unit.
l If the number of stored fault codes or fault patterns
exceeds ten, already stored fault codes will be erased,
in sequence beginning with the oldest.
l Do not disconnect the battery until all fault codes or
fault patterns have been read out, because all stored
fault codes or fault patterns will be canceled when the
battery is disconnected.
(3) If the fail-safe system is activated and the transaxle is
locked in 3rd gear, the fault code in the Fail-Safe Code
Description will be stored in the RAM.
Three of these fault codes can be stored.
(4) The cancellation will occur if, with the transaxle locked in
3rd gear, the ignition key is turned to the OFF position, but
the fault code is stored in the RAM.
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23-24AUTOMATIC TRANSAXLE - Troubleshooting
FAULT CODEDESCRIPTIONCode
No.Display PatternItemRemedial Action
Excessively large throttle
position sensor outputl Check throttle position sensor
connector.
l Check throttle position sensor
on bench.
12Excessively small throttle
position sensor outputl Adjust throttle position sensor.
l Check accelerator switch
(whether code number 24 is being
output).
13Defective or improperly
adjusted throttle position
sensor
14
Improperly adjusted throttle
position sensor
Open-circuited low-oil-
temperature sensorl Check oil temperature sensor
connector.
l Check oil temperature sensor on
bench.
16Short-circuited high-oil-
I-lMnnM-.temperature sensor
17
Open-circuited high-oil-
rlnnnruuvltemperature sensor or short-
circuited low-oil-temperature
sensor
Open-circuited kickdown servo
switch
Short-circuited kickdown servo
switchl Check kickdown servo switch
connector.
l Check kickdown servo switch on
bench.
Open-circuited ignition pulse
pickup cablel Check ignition pulse signal line.
24Open-circuited or improperly
adjusted accelerator switchl Check accelerator switch connector
l Check accelerator switch on bench.
l Adjust accelerator switch.
12A010412A0107
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AUTOMATIC TRANSAXLE - Troubleshooting23-25
L
L
ZodeNo.
31Display Pattern
ItemRemedial Action
Open-circuited pulse generator Al Check pulse generator A or B on
bench.
32l Check vehicle-speed reed switch
(chattering).
Open-circuited pulse generator B
Open-circuited shift control
solenoid valve Al Check solenoid valve connector.
l Check shift control solenoid valve
A on bench.
42Short-circuited shift control
solenoid valve A
Open-circuited shift control
solenoid valve Bl Check solenoid valve connector.
l Check shift control solenoid valve
B on bench.
Short-circuited shift control
solenoid valve B
45
uuuLNulM-Open-circuited pressure controll Check solenoid valve connector.
solenoid valvel Check pressure control solenoid
valve on bench.
46Short-circuited pressure
control solenoid valve
Open-circuited damper clutch
control solenoid valvel Check solenoid valve connector.
l Check damper clutch control
solenoid valve on bench.
Short-circuited damper clutch
control solenoid valve
49Defective damper clutch systeml Check damper clutch hydraulic
circuit.
lllJl!-l Check damper clutch control
solenoid valve on bench.0 Replace control unit.
12A010712A0105
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23-26AUTOMATIC TRANSAXLE - Troubleshooting
Code
No.Display PatternItemRemedial Action
1 st speed shift not finishl Check connectors of pulse
generators A and
B.l Check pulse generators A and B on
bench.
l Rear clutch slipping
52
uuuuu-ln-2nd speed shift not finishl Check connectors of pulse
generators A and B.
l Check pulse generators A and B on
bench.
l Rear clutch slipping
533rd speed shift not finishl Kickdown brake slipping
l Check connectors of pulse
generators A and B.
4th speed shift not finishl Check pulse generators A and B on
bench.
l Front clutch slipping
l Rear clutch slipping
l Check connectors of pulse
generators A and B.
l Check pulse generators A and B on
bench.
l End clutch slipping
6162l Kickdown brake slipping
Short-circuited torque
reduction request signal linel Check torque reduction request
or open-circuited torquesignal line.
reduction execution signal linel Check torque reduction execution
signal line.
Open-circuited torque reduction
request signal line0 Check torque reduction request
signal line.
63Short-circuited torque
reduction execution signal linel Check torque reduction execution
signal line.
12A0106
‘J
\J
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AUTOMATIC TRANSAXLE - Troubleshootinn23-27
FAIL-SAFE CODE DESCRIPTION
DdeVO.
81Display Pattern
Item
Open-circuited pulse
generator AFail-safe
Fixed at 3rd (D)or 2nd (2, L)Related
Self-Diagnosis3182Open-circulted pulse
Fixed at 3rd (D)32
generator Bor 2nd (2,
L)83Open- or short-circuited Fixed at 3rd
shift control solenoid
valve A
41,4284Open- or short-circuited Fixed at 3rd
shift control solenoid
valve B
43,4485Open- or short-circuited Fixed at 3rd (D)
45,46
uuu-pressure control
or 2nd
(2, L)solenoid valve
86Shift not finishFixed at 3rd (D)
51,52
uuumor 2nd (2,
L)53,54
12L0296
i
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23-28AUTOMATIC TRANSAXLE - Troubleshooting
INSPECTION OF CONTROL SYSTEMCheck the control system by using the multi-use tester and following the procedure given below.
CONTROL SYSTEM INSPECTION TABLE
Check Item
sensor
l Data listl Item No. 15Cold engine (before start)nglne warming up
l Data listl Item No. 23
or circuitharness
Item No. 26
lerator pedal switchl
Item No. 27l Defective inhibitor switch circuitl Defective TPS circuitl
Defective pulse generator A
shielded wire
l External noise interference
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