Mitsubishi Galant. Manual - part 386

GENERAL DESCRIPTION

TSB Revision

AUTOMATIC TRANSAXLE

23A-11

SHIFT PATTERN CONTROL

<2.4L ENGINE> UPSHIFT PATTERN

<2.4L ENGINE> DOWNSHIFT PATTERN

AC001949AC

100

50

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

1

2

2

3

3

4

THROTTLE
OPENING (%)

2 

→ 

3

MOVEMENT
RANGE

3

→

4

MOVEMENT
RANGE

0 (0)

50 (31)

100 (62)

150 (93)

200 (124)

OUTPUT SHAFT SPEED (r/min)

VEHICLE SPEED [km/h (mph)]

THICK LINE: STANDARD SHIFT PATTERN 

AC001950

100

50

0

0(0)

1,000

2,000

3,000

4,000

5,000

6,000

7,000

50 (31)

100 (62)

150 (93)

200 (124)

1

2

2

3

3

4

1

2 (L)

2

3 (2,L)

3

4 (3,2,L)

THROTTLE
OPENING (%)

OUTPUT SHAFT SPEED (r/min)

VEHICLE SPEED [km/h (mph)]

AC

GENERAL DESCRIPTION

TSB Revision

AUTOMATIC TRANSAXLE

23A-12

<3.0L ENGINE> UPSHIFT PATTERN 

<3.0L ENGINE> DOWNSHIFT PATTERN 

AC004258

100

50

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

0 (0)

50 (31)

100 (62)

150 (93)

200 (124)

THROTTLE
OPENING (%)

OUTPUT SHAFT SPEED (r/min)

VEHICLE SPEED [km/h (mph)]

1

2

2

3

3

4

2 

→

 3

MOVEMENT
RANGE

3 

→

 4

MOVEMENT
RANGE

THICK LINE: STANDARD SHIFT PATTERN

AB

AC004259

100

50

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

0 (0)

50 (31)

100 (62)

150 (93)

200 (124)

1

2

2

3

3

4

1

2 (L)

2

3 (2, L)

3

4 (3, 2, L)

THROTTLE
OPENING (%)

OUTPUT SHAFT SPEED (r/min)

VEHICLE SPEED [km/h (mph)]

AB

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-13

AU TO M ATIC  TR A N SA XLE DIAG NO SIS

DIAGNOSTIC TROUBLESHOOTING FLOW

M1231013500029

INTRODUCTION TO A/T DIAGNOSIS

M1231012300055

The mounting could be incorrect, the A/T fluid may 
be low, or a component of the transaxle may be 
faulty in the following conditions: noise or vibration is 
generated, A/T fluid leaks, the vehicle does not move 
forward or backward.

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

A/T DIAGNOSTIC TROUBLESHOOTING STRATEGY

M1231007600072

Use these steps to plan your diagnostic strategy. If 
you follow them carefully, you will be sure that you 
have exhausted most of the possible ways to find an 

A/T fault.

 

Gather information from customer.

Check the automatic transmission
fluid.

Verify complaint.

Replace or replenish the automatic
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 trouble symptom.

Performing the essential service.

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

NG

OK

OK

NG

AC005120AB

AUTOMATIC TRANSAXLE DIAGNOSIS

TSB Revision

AUTOMATIC TRANSAXLE

23A-14

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 

Code (DTC).

4. If you cannot 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.00-8

.

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

DTCs, or the system cannot communicate with 
the scan tool, refer to the Symptom Chart.

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

then erase the code from memory using the scan 
tool.

7. Reconfirm the symptom using the Road Test.

8. If DTC is set again, go to Inspection Chart for 

Diagnostic Trouble Codes.

9. If 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.00-8

.

10.After repairs are completed, conduct a Road Test 

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

A/T DIAGNOSTIC TROUBLE CODE DIAGNOSIS

M1231007700057

ON-BOARD DIAGNOSTICS

The powertrain control module (PCM) monitors its 
input/output signals (some signals all time and others 
under specified conditions). When an irregular signal 
is initially monitored, the PCM decides that a 
malfunction has occurred. There are 25 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 if the ignition switch is "LOCK" (OFF). 

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 the scan tool MUT-II 
(MB991502).

NOTE: If a sensor is disconnected with the ignition 
switch is "ON," a diagnostic trouble code is 
memorized. In this case, erase the DTC using the 
scan tool.
The 25 diagnostic items are all indicated sequentially 
from the smallest code number.

HOW TO READ AND ERASE DIAGNOSTIC 
TROUBLE CODES

Required Special Tools:
 MB991502: Scan Tool (MUT-II)

CAUTION

To prevent damage to scan tool MB991502, always turn the 
ignition switch to "LOCK" (OFF) position before 
connecting or disconnecting scan tool MB991502.

NOTE: If the battery positive voltage is low, diagnostic trouble 
codes will not be output. Check the battery if the scan tool 
cannot display.

NOTE:  If the battery is disconnected or if the powertrain 
control module connector is disconnected, the diagnostic 
trouble codes will be erased. Do not disconnect the battery or 
powertrain control module before the diagnostic trouble codes 
have been read.