Mitsubishi Montero (2004+). Manual — part 859

AUTOMATIC TRANSMISSION DIAGNOSIS

TSB Revision

AUTOMATIC TRANSMISSION

23A-11

AUTOMATIC TRANSMISSION DIAGNOSIS

DIAGNOSTIC TROUBLESHOOTING FLOW

M1231104000131

INTRODUCTION TO A/T DIAGNOSIS

M1231108400119

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 trans-
mission may be faulty.

The following items are suspected as causes for the
INVECS-II troubles: malfunction of the PCM, the
sensors, the switches, the harness or connectors.

Gather information from customer.

Check the transmission fluid.

Verify complaint.

Replace or replenish the
transmission fluid.

Communication with the scan tool
(MUT-II) not possible in Symptom
Chart.

Read the diagnostic trouble code.

Erase the diagnostic trouble code.

Check symptom.

Perform the repair.

Road test

Recheck diagnostic trouble codes
which were read before road test.

To DIAGNOSTIC TROUBLE CODE
CHART

To SYMPTOM CHART

Search for cause.

Repair

Confirmation test (road test)

INTERMITTENT MALFUNCTIONS
(Refer to GROUP 00, How to Use
Troubleshooting/Inspection
Service Points.)

Completed

NG

OK

Communication with the scan
tool (MUT-II) not possible

Diagnostic trouble code
displayed.

No diagnostic trouble code
displayed.

Abnormality exists (no diagnostic
trouble code)

Abnormality exists
(diagnostic trouble
code present)

No abnormality

No diagnostic trouble code
displayed.

Diagnostic trouble code
displayed.

Found

Not found

OK

OK

NG

AC205501

NG

AC

Communication with the scan tool
MB991958 (MUT-III sub assembly)
not possible in Symptom Chart.

Communication with the scan
tool MB991958 (MUT-III sub assembly)
not possible

AUTOMATIC TRANSMISSION DIAGNOSIS

TSB Revision

AUTOMATIC TRANSMISSION

23A-12

A/T DIAGNOSTIC TROUBLESHOOTING STRATEGY

M1231108500116

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.00-6

.

5. If you can verify the condition but there are no

DTCs, or the system can not communicate with
scan tool MB991958 (MUT-III sub assembly),
refer to the Symptom Chart

P.23A-42

.

6. If there is a DTC, record the number of the code,

then erase the code from memory using scan tool
MB991958 (MUT-III sub assembly).

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.00-6

.

10.After repairs are completed, conduct a Road Test

duplicating the complaint conditions to confirm the
malfunction has been eliminated.

DIAGNOSTIC FUNCTION

M1231103300010

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.

"N" range light flashing items

• Input shaft speed sensor

• Output shaft speed sensor

• Each solenoid valve

• Gear incorrect ratio

• A/T control relay system

CAUTION

If the "A/T TEMP" indicator light is illuminated, it means
that the transmission fluid temperature is too high. Stop
the vehicle in a safe place and wait until the "A/T TEMP"
indicator light extinguishes.

ON-BOARD DIAGNOSTICS

The powertrain control module (PCM) monitors its
input/output signals (some signals all the time and
others under specified conditions). When an irregular
signal is initially monitored, the PCM decides that a
malfunction has occurred and records the occur-
rence has diagnostic trouble code. There are 26
diagnostic items. The diagnostic results can be read
with a scan 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. Diagnostic trouble codes
will, however, be erased when a battery terminal or
the PCM connector is disconnected. In addition, the
diagnostic trouble code can also be erased by scan
tool MB991958 (MUT-III sub assembly).
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 scan tool MB991958 (MUT-III sub assem-
bly).
The 26 diagnostic items are displayed in numeric
order.

ACX01849AC

AUTOMATIC TRANSMISSION DIAGNOSIS

TSB Revision

AUTOMATIC TRANSMISSION

23A-13

HOW TO CONNECT THE SCAN TOOL (MUT-III)

Required Special Tools:

• MB991958: Scan Tool (MUT-III Sub Assembly)

• MB991824: Vehicle Communication Interface (V.C.I.)

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan 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 MB991911 to special tool MB991824.
5. Connect special tool MB991911 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 scan 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: Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.

NOTE: If the battery voltage is low, diagnostic trouble codes
will not be set. Check the battery if scan tool MB991958
does not display.

AC307591 AC

MB991911

MB991824

MB991827

AC307591

DATA LINK

CONNECTOR

AUTOMATIC TRANSMISSION DIAGNOSIS

TSB Revision

AUTOMATIC TRANSMISSION

23A-14

1. Connect scan 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 : Scan Tool (MUT-III Sub Assembly)

• MB991824: V.C.I.

• MB991827: MUT-III USB Cable

• MB991911: MUT-III Main Harness B

CAUTION

To prevent damage to scan tool MB991958, always turn the
ignition switch to the "LOCK" (OFF) position before con-
necting or disconnecting scan tool MB991958.
1. Connect scan 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.

AC307591 AC

MB991911

MB991824

MB991827

AC307591

DATA LINK

CONNECTOR

AC307591 AC

MB991911

MB991824

MB991827

AC307591

DATA LINK

CONNECTOR