2005 MITSUBISHI 380 automatic transmission

AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-12
AUTOMATIC TRANSMISSION DIAGNOSIS
DIAGNOSTIC TROUBLESHOOTING FLOWM1231013500353
INTRODUCTION TO A/T DIAGNOSISM1231012300226
The automatic transmission can exhibit any of the
following symptoms: noise or vibration is generated,
Transmission fluid leaks, the vehicle does not move
forward or backward. The causes of these symptoms
could come from: Incorrect mounting, the Transmis-
sion fluid may be low, or a component of the
transmission may be faulty. The following items are suspected as causes for the
INVECS-II troubles: malfunction of the A/T-ECU, the
sensors, the switches, the harness or connectors.

AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-13
A/T DIAGNOSTIC TROUBLESHOOTING STRATEGYM1231007600339
Use these steps to plan your diagnostic strategy. If
you follow them carefully, you will find most A/T mal-
functions.
1. Gather as much information as possible about the
complaint from the customer.
2. Verify that the condition described by the
customer exists.
3. Check the vehicle for any A/T Diagnostic Trouble
Codes (DTCs).
4. If you can not verify the condition and there are no
DTCs, the malfunction is intermittent. For
information on how to cope with intermittent
malfunctions, refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
How
to Cope with Intermittent Malfunction P.00-14.
5. If you can verify the condition but there are no
DTCs, or the system can not communicate with
diagnostic tool, refer to the Symptom Chart
P.23A-35.6. If there is a DTC, record the number of the code,
then erase the code from memory using
diagnostic tool.
7. Reconfirm the symptom with a Road Test.
8. If a DTC is set again, go to the Inspection Chart
for Diagnostic Trouble Codes.
9. If a DTC is not set again, the malfunction is
intermittent. For information on how to cope with
intermittent malfunctions, refer to GROUP 00,
How to Use Troubleshooting/Inspection Service
Points
How to Cope with Intermittent
Malfunction P.00-14.
10.After repairs are completed, conduct a Road Test
duplicating the complaint conditions to confirm the
malfunction has been eliminated.
DIAGNOSTIC FUNCTIONM1231022500135
CHECK "N" RANGE LIGHT
The "N" range light flashes once per second if there is an
abnormality in any of the items in the table below which are
related to the A/T system. Check for diagnostic trouble codes if
the "N" range light is flashing once per second.
NOTE: The "N" indicator lamp warning function does not
operate with the selector lever in the "P" (PARK), "R"
(REVERSE) or "N" (NEUTRAL) position.
"N" range light flashing items
Input shaft speed sensor
Output shaft speed sensor
Each solenoid valve
Gear incorrect ratio
A/T control relay system
If the "N" range light is flashing rapidly (twice per second),
the transmission fluid temperature is too high. (It flashes
when the fluid is approximately 125
C or more and goes
off when the fluid is approximately 115
C or less)
ON-BOARD DIAGNOSTICS
The automatic transmission -electronic control unit
(A/T-ECU) monitors its input/output signals (some
signals all the time and others under specified condi-
tions). When an irregular signal is initially monitored,
the A/T-ECU decides that a malfunction has
occurred and records the occurrence as a diagnostic
trouble code. The diagnostic results can be read with diagnostic tool. Diagnostic trouble codes are kept in
memory by direct battery feed. The codes are
retained in memory even if the ignition switch is in
the "LOCK" (OFF) position. DTCs are not erased
even after the battery terminals and the A/T-ECU
connector are disconnected. In addition, the diagnos-
tic trouble code can also be erased by diagnostic
tool.

AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-14
NOTE: If a sensor is disconnected when the ignition
switch is in the "ON" position, a diagnostic trouble
code is stored in memory. In this case, erase the
DTC using diagnostic tool.The diagnostic items are displayed in numeric order.
HOW TO CONNECT THE DIAGNOSTIC TOOL
(MUT-III)
Required Special Tools:
MB991958: Diagnostic Tool (MUT-III Sub Assembly)
MB991824: Vehicle Communication Interface (V.C.I.)
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A
To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958.
1. Ensure that the ignition switch is at the "LOCK" (OFF)
position.
2. Start up the personal computer.
3. Connect special tool MB991827 to special tool MB991824
and the personal computer.
4. Connect special tool MB991910 to special tool MB991824.
5. Connect special tool MB991910 to the data link connector.
6. Turn the power switch of special tool MB991824 to the "ON"
position.
NOTE: When special tool MB991824 is energized, special
tool MB991824 indicator light will be illuminated in a green
color.
7. Start the MUT-III system on the personal computer.
NOTE: Disconnecting diagnostic tool MB991958 is the reverse
of the connecting sequence, making sure that the ignition
switch is at the "LOCK" (OFF) position.
HOW TO READ AND ERASE DIAGNOSTIC
TROUBLE CODES
Required Special Tools:
MB991958: Diagnostic Tool (MUT-III Sub Assembly)
MB991824: V.C.I.
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A

AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-15
To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958.
NOTE: If the battery voltage is low, diagnostic trouble codes
will not be set. Check the battery if diagnostic tool
MB991958 does not display.
1. Connect diagnostic tool MB991958 to the data link
connector.
2. Turn the ignition switch to the "ON" position.
3. Select "Interactive Diagnosis" from the start-up screen.
4. Select "System select."
5. Choose "ELC-A/T" from the "POWER TRAIN" tab.
6. Select "MITSUBISHI."
7. Select "Diagnostic Trouble Code."
8. If a DTC is set, it is shown.
9. Choose "Erase DTCs" to erase the DTC.
HOW TO READ DATA LIST
Required Special Tools:
MB991958 : Diagnostic Tool (MUT-III Sub Assembly)
MB991824: V.C.I.
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A
To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958.
1. Connect diagnostic tool MB991958 to the data link
connector.
2. Turn the ignition switch to the "ON" position.
3. Select "Interactive Diagnosis" from the start-up screen.
4. Select "System select."
5. Choose "ELC-A/T" from the "POWER TRAIN" tab.
6. Select "MITSUBISHI."
7. Select "Data List."
8. Choose an appropriate item and select the "OK" button.

AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-16
HOW TO PERFORM ACTUATOR TEST
Required Special Tools:
MB991958: Diagnostic Tool (MUT-III Sub Assembly)
MB991824: V.C.I.
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A
To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958.
1. Connect diagnostic tool MB991958 to the data link
connector.
2. Turn the ignition switch to the "ON" position.
3. Select "Interactive Diagnosis" from the start-up screen.
4. Select "System select."
5. Choose "ELC-A/T" from the "POWER TRAIN" tab.
6. Select "MITSUBISHI."
7. Select "Actuator Test."
8. Choose an appropriate item and select the "OK" button.
HOW TO DIAGNOSE THE CAN BUS LINES
Required Special Tools:
MB991958: Diagnostic Tool (MUT-III Sub Assembly)
MB991824: V.C.I.
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A

AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-17
To prevent damage to diagnostic tool MB991958, always
turn the ignition switch to the "LOCK" (OFF) position
before connecting or disconnecting diagnostic tool
MB991958.
1. Connect diagnostic tool MB991958 to the data link
connector.
2. Turn the ignition switch to the "ON" position.
3. Select "CAN bus diagnosis" from the start-up screen.
4. When the vehicle information is displayed, confirm that it
matches the vehicle whose CAN bus lines will be
diagnosed.
If they match, go to step 8.
If not, go to step 5.
5. Select the "view vehicle information" button.
6. Enter the vehicle information and select the "OK" button.
7. When the vehicle information is displayed, confirm again
that it matches the vehicle whose CAN bus lines will be
diagnosed.
If they match, go to step 8.
If not, go to step 5.
8. Select the "OK" button.
9. When the optional equipment screen is displayed, choose
the one which the vehicle is fitted with, and then select the
"OK" button.
HOW TO INITIALIZE A/T LEARNING VALUEM1231022600121
AIM
The use of EEPROM has enabled the A/T learned
value to be retained even after the battery terminals
are disconnected. However, the learned value should
be initialized if the A/T assembly, the engine assem-
bly, the valve body assembly or the solenoid valves
are replaced. The initialization procedure is as
below:
INITIALIZATION PROCEDURE
1. Shift the selector lever to the P range and turn the
ignition switch to the LOCK (OFF) position. Then,
connect the MUT-III to the diagnosis connector.
2. Initialize the learned value on the initialization
screen.
3. After this initialization, make the system learn the
idling in accordance with "Learning procedure for
idling in MPI engine" (Refer to GROUP 00

Precautions before Service 00-22).

AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-18
FAIL-SAFE/BACKUP FUNCTIONM1231008300234
When a malfunction of a main sensor or actuator is
detected by the A/T-ECU, the transmission is con-
trolled by pre-set control logic to maintain safe condi-
tions for driving.The following table shows how the fail-safe/backup
function affects vehicle driveability and operation.
MALFUNCTIONING ITEM JUDGEMENT
CONDITIONCONTROL DEFAULT DURING MALFUNCTION
Input shaft speed sensor If no output pulse
from the input shaft
speed sensor is
detected for one
second or more
when the vehicle
speed is 30 km/h (19
mph) or greater.The diagnostic trouble code is recorded when the
malfunction occurs during 4 monitoring periods in
one drive cycle. When the judgment condition is
met, the transmission holds 3rd gear or 2nd gear,
depending on speed, as a fail-safe.
Output shaft speed sensor The output signal
from the output shaft
speed sensor is not
present for one
second or more
while the vehicle is
driven.The diagnostic trouble code is recorded when the
malfunction occurs during 4 monitoring periods in
one drive cycle. When the judgment condition is
met, the transmission holds 3rd gear or 2nd gear,
depending on speed, as a fail-safe.
Low-reverse solenoid valve Solenoid valve
resistance is below
2.7 ohms for 0.32
seconds.The diagnostic trouble code is recorded when the
malfunction occurs during 5 monitoring periods in
one drive cycle. When the judgment condition is
met, the A/T control relay is turned off. The
transmission will only operate in 3rd and reverse
gears until the system is repaired. Underdrive solenoid valve
Second solenoid valve
Overdrive solenoid valve
Reduction (RED) solenoid valve
Damper control clutch (DCC)
solenoid valve
Incomplete shifting 1st The gear ratio value
from the output shaft
speed sensor is not
the same as the
output from the input
shaft speed sensor
for one second after
shifting has been
completed.The diagnostic trouble code is recorded when the
malfunction occurs during 5 monitoring periods in
one drive cycle. When the judgment condition is
met, the A/T control relay is turned off. The
transmission will only operate in 3rd and reverse
gears until the system is repaired. 2nd
3rd
4th
5th
Reverse
A/T control relay A/T control relay
voltage is less than
seven volts for 0.1
second after the
ignition switch is
turned "ON."The A/T control relay is switched off. The
transmission will only operate in 3rd and reverse
gears until the system is repaired.
Malfunction in the A/T-ECU Malfunction has
occurred in the
A/T-ECU.The A/T control relay is switched off. The
transmission will only operate in 3rd and reverse
gears until the system is repaired.

AUTOMATIC TRANSMISSION DIAGNOSIS
AUTOMATIC TRANSMISSION23A-19
ROAD TESTM1231007800407
Check using the following procedures.
STEP CONDITION
BEFORE
TEST/OPERATIONTEST/OPERATION STANDARD INSPECTION
ITEMINSPECTION
PROCEDURE
PA G E
1 Ignition switch:
(LOCK) OFFIgnition switch
(1) ONData list No.8
(1) Control Relay
Voltage [V]A/T Control
relay
output
voltageA/T Control
relay system
(P.23A-207).
2 Ignition switch:
ON
Engine: Stopped
Transmission
range: PTransmission range
(1) P, (2) R, (3) N, (4)
DData list No.34
(1) P, (2) R, (3) N, (4)
DTransmissi
on range
switchTransmission
range switch
system
(P.23A-97,
P.23A-119).
Transmission range
(1) D (1st gear)
(2) Select the sport
mode (1st gear)
(3) Upshift and hold
the selector lever in
that position (2nd
gear)
(4) Downshift and
hold the selector
lever in that position
(1st gear)Data list No.27
(1) OFF, (2) ON, (3)
ON, (4) ON
Data list No.28
(1) OFF, (2) OFF, (3)
ON, (4) OFF
Data list No.29
(1) OFF, (2) OFF, (3)
OFF, (4) ONSelect
switch and
Shift switchShift switch
assembly
system
(P.23A-252).
Brake pedal
(1) Depressed
(2) ReleasedData list No.19
(1) ON
(2) OFFSto pl amp
switchSt o pla mp
switch system
(P.23A-89).
3 Ignition switch:
ST
Engine: StoppedCranking test with
lever in P or N rangeCranking should be
possibleCranking Engine does
not crank
(P.23A-218).
4 Engine warming
upDrive for 15 minutes
or more so that the
transmission fluid
temperature
becomes 70
90CData list No.7
Gradually rises to 70
90CTransmissi
on fluid
temperatur
e sensorTransmission
fluid
temperature
sensor system
(P.23A-36,
P.23A-47).
5 Engine: Idling
Transmission
range: NBrake pedal (Retest)
(1) Depressed
(2) ReleasedData list No.19
(1) ON
(2) OFFSto pl amp
switchSt o pla mp
switch system
(P.23A-89).
Transmission range
(1) N
D
(2) N
RShould be no
abnormal shift
shocks
Time delay when
engaging should be
within 2 secondsMalfunction
when
startingEngine stalls
when moving
selector lever
from N to D or
N to R
(P.23A-227).